Based on aggregated retail and installation data, Pergo laminate costs about $4.20 to $6.30 per square foot installed and SmartCore vinyl plank about $5.30 to $7.40. On a 400-square-foot room that is roughly $1,680 to $2,515 for Pergo laminate against $2,120 to $2,955 for SmartCore — a difference of about $440, and all of it is material. Installation labor is the same for both, because both are click-lock floating floors priced at the same per-square-foot rate.
That $440 is the answer only to half of the question. “Pergo vs SmartCore” usually compares two different kinds of floor: Pergo is best known for laminate, which has a wood-fiber core, and SmartCore is vinyl plank, which does not. Pergo also sells vinyl, and its vinyl line — DuraCraft — costs the same as SmartCore on the shelf, carries a similar wear surface and sits in the same store. So this page runs two comparisons:
- Pergo laminate vs SmartCore — the comparison most shoppers are actually making. Cheaper to buy, but it trades roughly $440 of savings against a water event that can cost several times that.
- Pergo DuraCraft vs SmartCore — the like-for-like one. Near-identical price, near-identical install, and the differences sit in the spec sheet and the warranty wording.
The generic category comparison — every laminate against every vinyl plank — is on the laminate vs vinyl plank cost page. This page is about the two brands, the specific lines, and what each one costs in a real room over its life.
Two Brands, Two Different Shelves
Pergo: a Mohawk brand that sells three categories
Pergo is a brand of Mohawk Industries. Its own catalog splits into laminate, resilient/vinyl and hardwood, and within those it runs ten named product lines, several of which are sold through only one retailer. The wording in the table is Pergo’s own, taken from its line pages.
| Pergo line | Category | Where Pergo lists it | Water feature, as Pergo describes it |
|---|---|---|---|
| TimberCraft | Laminate | Lowe’s only | WetProtect — water-tight joints, waterproof finish, lifetime surface and subfloor warranty |
| Pro | Laminate | Lowe’s only | WetProtect |
| Pro+ | Laminate | Lowe’s | WetProtect, plus a lifetime pet scratch warranty |
| Elements | Laminate | Not stated on the line page | Originals tier: 10-year waterproof; Preferred and Ultra tiers: lifetime WetProtect |
| Outlast+ | Laminate | The Home Depot | SpillProtect — tight locking joints and a waterproof surface coating that keep spills on the surface |
| XP / XP+ | Laminate | The Home Depot | Entry tier listed as “24 hour water resistant”; step-up tier with SpillProtect |
| DuraCraft | Luxury vinyl | Lowe’s | WetProtect; 22 mil wear layer |
| Extreme | Luxury vinyl | Not stated on the line page | WetProtect Gold “floodproof” warranty, worded to cover leaks and minor floods “from all directions” |
| EverCraft | Hybrid resilient (PVC-free) | Lowe’s | WetProtect; lifetime pet scratch warranty |
| Fusion | Hybrid resilient (PVC-free) | The Home Depot | Waterproof surface and water-tight joints |
Two things fall out of this. First, “Pergo” is not a price or a spec — it is ten products spanning two core materials. Second, the laminate lines’ water protection is engineered around keeping water on top of the plank; only one line, the Extreme vinyl, has a warranty worded around water arriving from any direction. That distinction becomes a dollar figure further down.
SmartCore: a Lowe’s-exclusive vinyl line
Every SmartCore vinyl plank product in the Lowe’s listing sampled in August 2026 — 40 of them — was tagged as a Lowe’s exclusive, and the product names carry the sub-brand “By COREtec Floors.” The full COREtec range is sold through flooring dealers rather than Lowe’s, and prices from a higher base: its cheapest line, Pro Classics, carries the same 20 mil wear layer as SmartCore Pro at a $4.09 per square foot dealer price, and the COREtec flooring cost data prices every current COREtec line from there up to $9.69. The line splits into four families:
| SmartCore family | Wear layer | Plank thickness | Install method | Commercial warranty on sampled product |
|---|---|---|---|---|
| SmartCore (5-in planks) | 12 mil | 6.5 mm | Click-lock, attached pad | 15-year limited, plus limited lifetime residential |
| SmartCore Ultra / Ultra XL | 12 mil | not stated on listing | Click-lock, attached pad | — |
| SmartCore Pro | 20 mil | 6 mm | Click-lock, attached pad | 20-year limited, plus limited lifetime residential |
| SmartCore (7-in, 22 mil) | 22 mil | 7.5 mm | Click-lock or glue-down, attached pad | 30-year limited, plus limited lifetime residential |
Across the whole 40-product listing, 18 products carry a 12 mil wear layer, 4 carry 20 mil and 18 carry 22 mil; 38 of the 40 list underlayment as included, and 18 of the 40 can be glued down as well as clicked. Lowe’s product copy describes the 22 mil line as WPC construction — a foamed vinyl core — which matters for dents. SmartCore also sells an engineered hardwood line, SmartCore Naturals, which is a different product category again and is not what most “Pergo vs SmartCore” searches mean.
The Like-for-Like Matchup: DuraCraft vs SmartCore
Put the vinyl products side by side and the brand gap nearly disappears. The table uses individual products sampled from Lowe’s listings in 2026; shelf prices move with promotions and region, so read them as a snapshot of where each line sits rather than a quote.
| Spec | Pergo DuraCraft (sampled) | SmartCore Pro (sampled) | SmartCore 22 mil (sampled) | SmartCore 12 mil (sampled) |
|---|---|---|---|---|
| Category | Luxury vinyl plank | Luxury vinyl plank | Luxury vinyl plank (WPC) | Luxury vinyl plank |
| Wear layer | 22 mil (other DuraCraft listings 20 mil) | 20 mil | 22 mil | 12 mil |
| Thickness | 6 mm | 6 mm | 7.5 mm | 6.5 mm |
| Install | Click-lock floating | Click-lock floating | Click-lock or glue-down | Click-lock floating |
| Attached pad | Yes | Yes | Yes | Yes |
| Warranty | Lifetime residential / 30-year commercial | Limited lifetime residential / 20-year limited commercial | Limited lifetime residential / 30-year limited commercial | Limited lifetime residential / 15-year limited commercial |
| Shelf price | $3.19/sq ft | $3.69/sq ft | $3.69/sq ft | $3.19/sq ft |
Read across the rows and the only material differences are plank thickness (7.5 mm on SmartCore’s 22 mil line against 6 mm elsewhere, which bridges minor subfloor flaws better), the glue-down option on that same SmartCore line, and the commercial warranty term, which runs from 15 to 30 years depending on which product is on the box. On a 400-square-foot room, the $0.50 per square foot gap between the $3.19 and $3.69 products is about $220 of material once waste is included — smaller than the swing between two installers’ quotes for the same room.
Some Pergo lines carry a term SmartCore’s listings do not state: a lifetime pet scratch warranty, which Pergo attaches to EverCraft and Fusion (its PVC-free hybrid lines) and to Pro+ laminate — not to DuraCraft. It is a warranty term, not a hardness rating; what it covers on a claim is in the warranty document, not the marketing line.
Shelf Prices at the One Store That Sells Both
Lowe’s is the only chain that stocks SmartCore, and it also stocks both Pergo laminate and Pergo vinyl, which makes its listings the cleanest like-for-like price sample available. The price-band counts below are read from Lowe’s own “price per sq. ft.” filters on three listings sampled between January and August 2026.
| Listing | Products | $1.00–$1.99 | $2.00–$2.99 | $3.00–$3.99 | $4.00–$4.99 |
|---|---|---|---|---|---|
| Pergo laminate | 50 | 1 | 37 | 11 | 1 |
| Pergo vinyl plank | 49 | — | 6 | 41 | 2 |
| SmartCore vinyl plank | 40 | 1 | 2 | 34 | 3 |
The pattern is clean: Pergo laminate clusters about $1 per square foot below both vinyl products, and Pergo vinyl and SmartCore cluster in the same band. The laminate listing also shows what that dollar buys: of the 40 Pergo laminate products carrying an AC rating, 29 were AC4 and 11 AC3; 33 of the 50 were 10 mm thick, 15 were 12 mm and 2 were 14 mm; and 44 of the 50 were tagged waterproof.
Two cautions sit on these numbers. Most of the products in each listing carried a running promotion at the time of sampling — 30 of 40 SmartCore products and 33 of 50 Pergo laminate products — so the shelf price on a given week can sit a band lower. And the per-square-foot price excludes sales tax, delivery and the roughly 10 percent waste allowance an installer orders, all of which are added in the room figures below.
What Each Costs Installed, Room by Room
The installed figures on this page are built from two inputs: the shelf-price band each brand clusters in, and a labor rate that does not depend on the brand. They are cross-checked against the site’s project data for the two categories:
| Project data | Typical job total | Materials | Labor |
|---|---|---|---|
| Laminate installation | $900–$3,200 (mid $1,800) | $300–$1,400 (mid $700) | $600–$1,800 (mid $1,100) |
| Vinyl plank installation | $1,500–$5,500 (mid $3,000) | $700–$2,500 (mid $1,400) | $600–$2,700 (mid $1,400) |
The vinyl labor band reaches higher at the top because it covers glue-down installs, which run $3 to $8 per square foot in labor; laminate is laid floating. For a click-lock floating install — how both Pergo laminate and nearly every SmartCore plank goes down — aggregated labor data puts the rate at roughly $2 to $3 per square foot for either, and that is the rate used below. Material is priced at each brand’s dominant band with 10 percent added for waste.
| Room size | Pergo laminate materials | SmartCore materials | Labor (either brand) | Pergo laminate installed | SmartCore installed | Gap |
|---|---|---|---|---|---|---|
| 200 sq ft (bedroom) | $440–$660 | $660–$880 | $400–$600 | $840–$1,260 | $1,060–$1,480 | $220 |
| 400 sq ft (living + dining) | $880–$1,315 | $1,320–$1,755 | $800–$1,200 | $1,680–$2,515 | $2,120–$2,955 | $440 |
| 600 sq ft (open main floor) | $1,320–$1,975 | $1,980–$2,635 | $1,200–$1,800 | $2,520–$3,775 | $3,180–$4,435 | $660 |
Pergo’s vinyl lines price the same as SmartCore here, because they sit in the same $3 to $4 shelf band — so the SmartCore column doubles as the DuraCraft column. Per square foot, the table works out to $4.20 to $6.30 installed for Pergo laminate and $5.30 to $7.40 for SmartCore or Pergo vinyl.
The gap column is the whole brand decision in one number: about $1.10 per square foot of floor, or $110 per 100 square feet, and it does not grow with labor. A bigger room widens it; a more expensive installer does not.
What the Quote Adds That the Shelf Price Does Not
A shelf price is one line of a flooring quote. These are the lines that sit beside it, and none of them depends on which brand is on the box — they are the same whether the plank is Pergo or SmartCore.
- Old floor removal. Carpet and pad come up for about $1 to $2 per square foot; glued-down tile runs $2 to $5. A whole-project floor removal commonly runs $300 to $1,800.
- Subfloor flatness. Both are floating floors, and floating floors flex at the seams over a dip. Laminate manufacturers commonly specify flatness within about 3/16 inch over 10 feet; leveling compound runs $2 to $4 per square foot, and subfloor replacement $900 to $3,000 for a typical job. SmartCore’s 7.5 mm, 22 mil line is the thickest product in this comparison and bridges minor flaws best.
- Underlayment. Mostly already paid for: 38 of the 40 SmartCore products list underlayment as included, and Pergo lists an attached pad on TimberCraft, Pro, Pro+ and Elements. A separate roll, where one is used, runs about $0.30 to $1.50 per square foot.
- Transitions and quarter round. Every floating floor stops short of walls and doorways. Trim and transitions commonly add $150 to $400 on a multi-room job of about 400 square feet.
- Stairs. Priced per step, not per square foot: roughly $60 to $150 per step for laminate and $40 to $100 for vinyl plank, with a matching stair-nose piece on each tread.
- Glue-down, if chosen. The 18 SmartCore products listed for glue-down add roughly $1 to $3 per square foot in labor over a floating install — about $400 to $1,200 on 400 square feet — and make single-plank repairs faster later.
On a 400-square-foot carpeted room that needs carpet removal and trim but no leveling, those lines add roughly $550 to $1,200 to either brand’s installed figure.
Where Each One Fails, in Dollars
Both brands are sold as waterproof, scratch-resistant and pet-friendly. The figures below price what happens when that claim runs out — the failure each floor is physically more exposed to, and the cost to put it right. The repair costs are the site’s aggregated figures from the water damaged floor repair and most durable flooring data.
Water that gets under the floor
A spill on top of the floor is the easy case, and both brands handle it: Pergo’s WetProtect and SpillProtect lines are built to hold water on the surface long enough to wipe it up. The expensive case is water that arrives underneath or through the seams over hours — a dishwasher supply line, a toilet overflow found the next morning, a washing machine hose. Then the core material decides the bill.
| Scenario: 400 sq ft floating floor, water under the planks | Pergo laminate | SmartCore (or Pergo DuraCraft) |
|---|---|---|
| What the core does | Wood-fiber core absorbs water and swells at the joints; swelling does not reverse on drying | Vinyl core does not absorb water |
| Typical repair path | Tear out and replace | Lift planks, dry the subfloor, relay the same planks |
| Tear-out | $400–$800 ($1–$2/sq ft) | — |
| Flooring cost | $1,680–$2,515 (new floor, installed) | $400–$1,200 (lift, dry, relay at $1–$3/sq ft) |
| Flooring line after the event | $2,080–$3,315 | $400–$1,200 |
Drying the room — extraction, dehumidifiers, air movers — is left out of both columns because it costs the same under either floor. What remains is a difference of roughly $1,700 to $2,100 on the flooring line alone.
Set that against the $440 Pergo laminate saves at install on the same room, and the break-even is simple arithmetic: if the chance of one under-floor water event during the floor’s life is higher than about 1 in 4 to 1 in 5 ($440 divided by $1,680 to $2,115), the SmartCore floor is the cheaper one to own. In a kitchen, laundry room or full bathroom — the rooms with a supply line and an appliance — that threshold is not a high bar. In a bedroom it is.
This is the uninsured case. Pergo’s WetProtect lines carry a lifetime surface and subfloor warranty; if a claim pays, the laminate figure shrinks to whatever the warranty leaves uncovered. A warranty’s exclusions sit in the warranty document rather than the product page, and the table above is the cost when a claim does not apply. Among Pergo’s line pages, only Extreme — a vinyl line — carries warranty wording aimed at water from “all directions.” The wider picture, every floor type ranked by what a leak costs, is on the best waterproof flooring page.
Dents and point loads
This is where the vinyl products give ground. A refrigerator on its feet, a piano or a loaded bookcase concentrates hundreds of pounds on a few square inches, and a foamed vinyl core — the WPC construction Lowe’s describes on SmartCore’s 22 mil line — can take a permanent indentation under that load. Laminate’s fiberboard core is harder and resists indentation better, though a dropped heavy object can chip a laminate plank’s edge.
The repair is the same for both, because both are floating: unclick the floor from the nearest wall back to the damaged plank, swap it, re-click. Aggregated repair data puts that at $150 to $450 per incident, and it depends on having a spare box of the same product — both brands’ lines turn over, so a matching plank bought later is not guaranteed. Setting aside 5 to 10 percent extra at install is roughly $40 to $120 of Pergo laminate or $60 to $160 of SmartCore on a 400-square-foot job.
Scratches, claws and grit
Abrasion is laminate’s strongest property. Pergo laminate’s wear surface is rated on the AC scale, and 29 of the 40 AC-rated Pergo products in the sampled listing were AC4, the grade rated for general commercial traffic. SmartCore’s wear layer is measured in mils: 12 mil is the standard residential spec and 20 to 22 mil the heavier grade. The scales do not convert into each other — the most durable flooring page explains why — but both top grades are the ones a household with large dogs is paying for.
The price of that choice is small. Within SmartCore, the step from a 12 mil product to a 20 or 22 mil one was $0.50 per square foot in the sampled listings — about $220 on a 400-square-foot room. Within Pergo laminate, AC4 is already the majority of the shelf. Urine is the other pet failure and it follows the water table above: it pools at seams, and at a seam a fiberboard core swells where a vinyl core does not. The best flooring for pets guide prices a repeated accident on each floor type.
Sun and fading
Neither brand publishes a fade-resistance figure a buyer can compare; Pergo describes several laminate lines as “fade proof,” and SmartCore’s listings do not state a rating. The cost consequence is what both floors share: neither can be sanded or refinished, so a floor that fades or discolors in the shape of a window is fixed by replacing the affected run of planks — the same $150 to $450 unclick-and-swap as a dent for a small patch, or the full room figure from the table above if the whole floor has shifted color.
Cost Per Year of Service
Divide the installed cost by the years the floor stays down and the $440 gap shrinks to a few dollars a month. Based on aggregated data, laminate typically lasts 15 to 20 years and vinyl plank 10 to 20 years in residential use; by grade, AC4 laminate runs 20 to 25 years, as set out in how long laminate flooring lasts. The table uses a 400-square-foot room at the middle of each brand’s range: $2,100 for Pergo laminate and $2,540 for SmartCore.
| Years in service | Pergo laminate per year | SmartCore per year | Difference per year |
|---|---|---|---|
| 10 | $210 | $254 | $44 |
| 15 | $140 | $169 | $29 |
| 20 | $105 | $127 | $22 |
| 20, with one under-floor water event | $209–$271 | $147–$187 | laminate costs $62–$84 more |
The bottom row adds each floor’s post-event flooring bill from the water table, spread over the same 20 years. Without a water event, Pergo laminate is $22 to $44 a year cheaper to own than SmartCore. With one, the order flips and SmartCore is $62 to $84 a year cheaper. Per square foot, a 20-year dry-room life works out to about $0.26 per square foot per year for Pergo laminate and $0.32 for SmartCore. Every other floor type is ranked the same way on the cheapest flooring options page.
A long warranty does not change these numbers. A “limited lifetime residential” warranty is a statement about one layer of the plank under the conditions its document lists; a residential floor is usually replaced because it looks worn, dented or faded, not because a warranty failure occurred.
Labor: The Same Click, Different Details
For a crew, Pergo laminate and SmartCore are the same job: acclimate the cartons, check the subfloor, lay a floating floor from one wall with expansion gaps at the edges, undercut the door jambs, trim out. That is why the labor line is identical in every table on this page. The differences are small and specific:
| Detail | Pergo laminate | SmartCore |
|---|---|---|
| Locking system | Pergo’s patented Uniclic joint on its WetProtect laminate lines | Click-lock (“interlocking”) on all 40 products |
| Glue-down option | No — laid floating | Yes on 18 of 40 products (the 22 mil products in the samples) |
| Attached pad | TimberCraft, Pro, Pro+, Elements | 38 of 40 products |
| Typical project duration (site project data) | 1–3 days | 2–5 days |
| Thickest plank in this comparison | 12 mm (TimberCraft); 14 mm on 2 products | 7.5 mm (22 mil line) |
The duration difference in the project data reflects the vinyl category as a whole, including glue-down jobs and larger typical projects; a floating SmartCore bedroom goes down as fast as a Pergo laminate one. The full time breakdown by floor type, including acclimation, is on the flooring installation time page.
DIY math
Because the labor line is brand-neutral, the DIY saving is too. On a 400-square-foot room, a simple floating install avoids about $800 to $1,200 of labor for either brand — roughly two to three times the entire brand gap. One-time tools and supplies run about $75 to $200: a laminate cutter or saw ($20 to $40 a day to rent), a tapping block, pull bar and spacers ($15 to $30), and hand tools. The economics turn against DIY in the same places for both: stairs, rooms that need leveling first, and — for SmartCore’s 22 mil lines — a glue-down install, which is less forgiving of a mistake than a click joint that can be unlocked and relaid.
City-Adjusted: Labor Moves, the Brand Gap Does Not
Flooring material is priced broadly nationally, while installation labor follows local trade wages. The table applies each metro’s labor factor to the 400-square-foot mid-range room: $1,100 of Pergo laminate or $1,540 of SmartCore, plus $1,000 of labor either way.
| City | Labor Adjustment Factor | Pergo Laminate, 400 sq ft Room | SmartCore, 400 sq ft Room | Labor a DIY Install Avoids | vs. National |
|---|---|---|---|---|---|
| Minneapolis, MN | 1.27 | $2,370 | $2,810 | $1,270 | +27% |
| Philadelphia, PA | 1.12 | $2,220 | $2,660 | $1,120 | +12% |
| Denver, CO | 1.07 | $2,170 | $2,610 | $1,070 | +7% |
| Las Vegas, NV | 1.01 | $2,110 | $2,550 | $1,010 | +1% |
| Charlotte, NC | 0.92 | $2,020 | $2,460 | $920 | −8% |
| Tampa, FL | 0.87 | $1,970 | $2,410 | $870 | −13% |
Mid-range 400 sq ft room: materials at each brand's dominant shelf-price band plus 10% waste, held at the national figure; floating-install labor scaled by the metro factor.
Labor adjustment factors are derived from BLS Occupational Employment and Wage Statistics (May 2025): the median ratio of local to national hourly wages across the trades that do this work. How this is calculated.
The brand gap is the same $440 in every row, because it is a material gap. What changes by city is the labor column — and with it the value of doing the install yourself, which in the higher-wage metros is worth more than twice the difference between the two brands. The methodology page documents how each metro factor is measured from wage data.
Look, Feel and Sound Underfoot
Most of what separates these floors in a showroom is not on a price tag, but some of it does turn into a line item.
The wood is printed on both. Pergo markets its laminate as “laminated wood,” which describes the construction, not the surface: the grain is a printed image under a clear wear layer, on a wood-fiber core. SmartCore’s grain is also a printed film, on a vinyl core. Neither is solid wood, and neither can be sanded. Pergo spends its product copy on surface texture — TimberCraft’s UltraDef technology is described as recreating “knots, cracks and graining,” and the Elements Ultra tier as “up to 75 layers of texture.” On the SmartCore side, the Lowe’s listing splits the line between 23 products with a beveled edge and 17 with a pressed bevel, the detail that makes a plank read as individual boards rather than a sheet.
Vinyl is softer and quieter; laminate is harder. A fiberboard core over a thin pad gives a firm, slightly hollow sound under hard-soled shoes, and a vinyl core — especially a foamed WPC one — gives a softer, more muted step. That same softness is what lets a WPC core dent under a point load, so the feel and the dent row in the failure table are one property seen from two sides.
Sound rules can add a line. Some condominium and homeowner associations set a minimum impact-sound rating for hard floors on upper levels. Where an attached pad does not meet it, a separate acoustic underlayment runs about $0.80 to $1.50 per square foot — roughly $320 to $600 on 400 square feet, the same for either brand, and on its own close to the whole brand gap.
Emissions certification. All 40 SmartCore products in the sampled Lowe’s listing were tagged GREENGUARD Gold certified, a third-party indoor-air emissions label. Pergo positions two of its lines on material content instead: EverCraft and Fusion are described as PVC-free, with 70 percent total recycled content and an 80 percent renewable core. Neither claim changes the installed cost; both are the sort of spec that differs by line within a brand more than between the two brands.
Room by Room: Where Each Floor Is Exposed
The same data, sorted by the room the floor goes into. None of this is a verdict on either brand; it is where each floor’s weak property gets tested and what that test costs.
| Room | What gets tested | Pergo laminate exposure | SmartCore / DuraCraft exposure |
|---|---|---|---|
| Bedroom | Light abrasion, furniture | Low — AC4 is more than a bedroom tests | Low — 12 mil is the residential spec |
| Living / dining | Furniture point loads, sun, traffic lanes | Low; chips at edges under dropped weight | Dents under heavy point loads, most on foamed cores |
| Hallway / entry | Grit abrasion, wet boots | Strong on abrasion; wet boots are surface water | 20–22 mil holds up; 12 mil wears faster in a lane |
| Kitchen | Appliance supply lines, dropped pans | The $2,080–$3,315 water row applies | The $400–$1,200 water row applies; dents from dropped pans |
| Laundry / full bath | Standing and under-floor water | Highest exposure in the house | Low for the plank; the subfloor still needs drying |
| Basement on a slab | Moisture from below, occasional seepage | Water from below is outside the “keep it on the surface” design | Plank tolerates it; vapor barrier still needed |
For kitchens specifically — the room where the water row and the dent row meet — the kitchen flooring cost data prices every floor type against both. For below-grade rooms, the basement flooring guide covers slab moisture testing and what each floor does when the slab gets wet.
Related Flooring Costs
The two categories behind these brands have full cost pages of their own: laminate flooring installation at $900 to $3,200 for a typical job, priced by AC rating and thickness, and vinyl plank installation at $1,500 to $5,500, priced by wear layer and install method. The category-level trade-off, independent of brand, is on laminate vs vinyl plank cost. When water has already reached the floor, the water damaged floor repair page prices the whole cost stack from drying to joists. Every other floor type, with the calculator pre-set for flooring, is on the flooring cost hub, and the methodology page explains how the national ranges and the city adjustment are built.