Square Footage Calculator
Area Results
| Unit | Equals | Use Case |
|---|---|---|
| 1 square yard | 9 sq ft | Carpet, turf |
| 1 square meter | 10.76 sq ft | International specs |
| 1 acre | 43,560 sq ft | Land measurement |
| 1 hectare | 107,639 sq ft | Agriculture |
| 12×12 room | 144 sq ft | Standard bedroom |
Square Footage in Real Projects
An L-shaped or irregular room is just two or more rectangles. Divide it into simple sections, measure each one separately, and add the totals. Our calculator lets you add as many areas as you need. For rooms with closets, always measure the closet separately and include it — carpet and flooring installers charge by total square footage including closets and alcoves.
Square footage is the starting point for almost every outdoor material calculation. Once you have the area in square feet, you can convert to cubic yards for concrete or gravel (multiply by depth in feet, then divide by 27), or directly use it to estimate mulch, sod, seed, and pavers.
Square Footage by Common Room Size
| Room Type | Typical Dimensions | Square Feet | + 10% Waste |
|---|---|---|---|
| Bathroom (small) | 5 × 8 ft | 40 sq ft | 44 sq ft |
| Bathroom (master) | 10 × 12 ft | 120 sq ft | 132 sq ft |
| Bedroom (standard) | 12 × 12 ft | 144 sq ft | 158 sq ft |
| Bedroom (master) | 14 × 16 ft | 224 sq ft | 246 sq ft |
| Living Room (avg) | 15 × 20 ft | 300 sq ft | 330 sq ft |
| Kitchen (galley) | 8 × 14 ft | 112 sq ft | 123 sq ft |
| Kitchen (open) | 14 × 18 ft | 252 sq ft | 277 sq ft |
| Garage (1-car) | 12 × 22 ft | 264 sq ft | 290 sq ft |
| Garage (2-car) | 22 × 22 ft | 484 sq ft | 532 sq ft |
| Patio (small) | 10 × 12 ft | 120 sq ft | 132 sq ft |
| Patio (medium) | 14 × 20 ft | 280 sq ft | 308 sq ft |
| Driveway (single) | 10 × 30 ft | 300 sq ft | 330 sq ft |
| Driveway (double) | 20 × 30 ft | 600 sq ft | 660 sq ft |
For non-rectangular rooms, divide the space into rectangles or triangles, calculate each section separately, then add the totals. Our calculator above lets you add as many areas as needed and adds them automatically.
How to Measure Square Footage Accurately
- Use a 25-foot tape measure. Phone apps with AR measuring tools are convenient but typically off by 2–4%. For anything you're buying material for, use a real tape.
- Measure at the widest point of each wall. Don't measure along baseboards or trim — measure the actual wall-to-wall distance at floor level.
- Round up to the nearest inch. Then convert to feet by dividing by 12. Example: 11 ft 7 in becomes 11.58 ft (139 in ÷ 12).
- Sketch the room before you measure. Label every wall with its length. This catches missed alcoves, closets, and bay windows.
- Always include closets and alcoves separately. Most flooring installers charge by total covered square footage — including closets, even if you didn't plan to floor them.
- Subtract permanent fixtures only when relevant. For paint, do not subtract small windows or doors unless they account for more than 10% of the wall. For flooring, do subtract built-in cabinets, kitchen islands, and tub footprints.
- Add the waste factor LAST. Calculate raw square footage first, then multiply by 1.10 (most materials) or 1.15 (diagonal tile, hardwood, complex patterns). Do not eyeball it.
Paint Coverage by Room Size
| Wall Square Footage | 1 Coat (gallons) | 2 Coats (gallons) | Approx. Cost* |
|---|---|---|---|
| 200 sq ft (small bathroom walls) | 1 gal | 2 gal | $60–$90 |
| 400 sq ft (bedroom walls) | 2 gal | 3 gal | $90–$135 |
| 600 sq ft (large bedroom + ceiling) | 2 gal | 4 gal | $120–$180 |
| 800 sq ft (living room walls) | 3 gal | 5 gal | $150–$225 |
| 1,200 sq ft (whole-house interior) | 4 gal | 7 gal | $210–$315 |
| 2,000 sq ft (large home interior) | 6 gal | 11 gal | $330–$495 |
*Cost estimate based on $30–$45/gal mid-grade interior latex (Sherwin-Williams ProMar 200, Behr Premium Plus, Benjamin Moore Regal). Premium paints (Aura, Emerald) run $60–$90/gallon.
Standard coverage assumption: 1 gallon = 350–400 sq ft per coat on previously painted, smooth drywall. Reduce coverage by 20% for textured walls (knockdown, popcorn ceiling, orange peel) and 30% for unprimed drywall or bare wood. Color changes from dark to light typically require 3 coats including primer.
Flooring Material by Square Footage
| Material | Typical Box Coverage | Recommended Waste | Boxes for 200 sq ft Room |
|---|---|---|---|
| Vinyl Plank (LVP) | 23–30 sq ft/box | 10% | 8 boxes |
| Engineered Hardwood | 20–25 sq ft/box | 10–15% | 10 boxes |
| Solid Hardwood | 18–22 sq ft/box | 15% | 11 boxes |
| Laminate | 22–26 sq ft/box | 10% | 9 boxes |
| Ceramic Tile (12×12) | 15 sq ft/box (15 tiles) | 10–15% | 15 boxes |
| Porcelain Tile (24×24) | 16 sq ft/box (4 tiles) | 10% | 14 boxes |
| Carpet (broadloom) | 12 ft wide rolls | 10% + seam allowance | 22 sq yd order |
| Carpet Tiles | ~24 sq ft/box (24 tiles) | 5% | 9 boxes |
Box yield varies by manufacturer. Always verify the exact square footage on the product label before estimating quantity. Buy from one production run when possible — different dye lots can have noticeable color variations, especially in tile and carpet.
What Counts as Living Square Footage?
- Finished, heated rooms above grade
- Hallways and stairwells (counted on each level)
- Closets, pantries, and storage rooms
- Finished bonus rooms with permanent stairs
- Heated/cooled finished basements (sometimes — see notes)
- Unfinished basements (even if heated)
- Garages (attached or detached)
- Open-air porches, decks, balconies
- Sheds and outbuildings
- Areas with ceilings under 7 feet
- Unfinished attic space
Important caveat for basements: Most appraisers list finished basement space separately from above-grade square footage, even when fully finished and heated. A 2,000 sq ft above-grade home with a 1,000 sq ft finished basement is typically listed as "2,000 sq ft + 1,000 finished basement" — not 3,000 sq ft. This affects comparable-sales analysis significantly.
Sources of Truth for Your Home's Square Footage
| Source | Method | Reliability |
|---|---|---|
| Tax assessor record | Drive-by exterior measurement | Often outdated or wrong by 5–15% |
| Original blueprints/plans | Architect's gross calculation | Doesn't reflect renovations |
| Current MLS listing | Listing agent (varies) | May be inflated |
| Professional appraisal | ANSI Z765 measurement | Most accurate |
| Your own measurement | Room-by-room interior | Accurate if methodical |
Why Accurate House Square Footage Matters
- Real estate listings: Listed at the wrong size, you either overprice (no offers) or underprice (lost equity). A 100 sq ft error at $200/sq ft is $20,000.
- Property taxes: Most jurisdictions assess based on county records. If your record overstates your size, you're overpaying tax. Check your county's website annually.
- Insurance: Replacement cost coverage scales with square footage. Inaccurate figures lead to underinsurance or wasted premiums.
- HVAC sizing: Heating and cooling capacity is calculated per square foot. Wrong size = oversized unit (humidity issues) or undersized (high bills).
- Flooring estimates: Whole-house flooring quotes use square footage as the base. A 5% error on 2,000 sq ft is 100 extra sq ft of materials and labor.
- Energy audits and rebate programs: Many state energy programs require accurate square footage to determine rebate eligibility.