SqFt Calculator
A fast, no-friction square footage tool for the most common case: rectangle rooms. Type length and width, get the answer instantly.
Last updated:Quick Rectangle SqFt Calculator
This page is the lightweight version for the query "sqft calculator". If you need circles, triangles, trapezoids, L-shapes, irregular rooms, waste presets across shapes, or more detailed guidance, open the full square footage calculator.
Need more than a rectangle? Use the full square footage calculator for circle, triangle, trapezoid, L-shape, irregular room, and multi-room layouts.
Entering a Tape Reading Like 12 ft 7 in
This tool takes one number per field, not a feet box plus an inches box — some competing sqft calculators do offer a combined 12′ 7″ input, so here is the exact conversion instead of a shrug. One inch is 1 ÷ 12 = 0.0833 ft, so you add 0.0833 ft for every inch:
| Inches past the foot mark | Decimal feet | Exact fraction |
|---|---|---|
| 1 in | 0.0833 ft | 1/12 |
| 2 in | 0.1667 ft | 1/6 |
| 3 in | 0.25 ft | 1/4 |
| 4 in | 0.3333 ft | 1/3 |
| 5 in | 0.4167 ft | 5/12 |
| 6 in | 0.5 ft | 1/2 |
| 7 in | 0.5833 ft | 7/12 |
| 8 in | 0.6667 ft | 2/3 |
| 9 in | 0.75 ft | 3/4 |
| 10 in | 0.8333 ft | 5/6 |
| 11 in | 0.9167 ft | 11/12 |
| 12 in | 1.0 ft | a whole foot — carry it |
So 12 ft 7 in = 12 + 0.5833 = 12.583 ft (12.5833 ft exactly). Enter 12.583 with the unit set to ft, or switch the dropdown to in and enter the same wall as 151 inches — that path involves no rounding at all.
Worked Example: 12 ft 7 in × 10 ft
Three ways to enter the same room, and what each one costs you:
| What you type | Unit | Result shown | Error vs exact 125.8333 sq ft |
|---|---|---|---|
| 151 × 120 | in | 125.83 sq ft | none — the tool divides by 12 for you |
| 12.583 × 10 | ft | 125.83 sq ft | none at two decimals |
| 12.58 × 10 | ft | 125.80 sq ft | −0.03 sq ft (0.026%) |
Same room, all four conversion tiles: 11.69 sq m, 13.98 sq yd, 0.0029 acres, 18120 sq in. With the default 10% waste the order line reads 138.42 sq ft. Rounding a decimal-foot entry to two places is immaterial for a floor order but it does creep into perimeter work — 2 × (12.58 + 10) = 45.16 ft of skirting versus 45.17 ft exact.
What Is a SqFt?
"SqFt" is shorthand for square foot, the area of a square that is exactly 1 foot by 1 foot. It is the default unit for room sizing, flooring orders, paint estimates, and many construction bids in the United States.
Rectangle Formula
For a rectangle, use length × width. A 12 ft × 10 ft room is 120 sq ft. If your measurements are in inches, meters, centimeters, or yards, this tool converts them before calculating the area — each field has its own unit dropdown, so length in feet and width in inches is a valid pair of inputs.
How the Numbers Are Rounded
- The big square-foot figure always shows two decimals and a thousands separator:
120.00,10,000.00. - The conversion tiles keep two decimals for sq m and sq yd, four for acres, and none for sq in — and they drop trailing zeros, so 7 sq yd prints as
7rather than7.00. - Nothing is rounded before the math: conversions happen on full floating-point values, so the rounding is display-only.
- Copy Result copies only the primary square-foot line, not the conversions or the cost.
When to Use the Full Calculator Instead
- Use the full calculator when the room has cutouts, alcoves, or multiple sections.
- Use it for circles, triangles, trapezoids, L-shapes, or any irregular layout.
- Use it when you need whole-box counts — the full tool has a coverage-per-box field and rounds up.
- Use project-specific tools for flooring, tile, paint, roof area, and budgeting.
FAQ
How do I calculate sqft from length and width?
Multiply length by width in the same unit. For a rectangle in feet, sqft = length × width. A 12 ft by 10 ft room is 120 sq ft. If your measurements are in inches, yards, meters, or centimeters, change the unit in the dropdown next to each input and the tool will convert them for you.
How do I enter a measurement like 12 ft 7 in?
This tool has no combined feet-and-inches field, so convert first. Because 1 in = 0.0833 ft, the 7 in is 0.5833 ft, which makes 12 ft 7 in = 12.583 ft — type 12.583 with the unit on ft. Or stay in inches: 12 ft 7 in is 151 in, so enter 151 × 120 with both units on in and the tool returns 125.83 sq ft with no manual rounding. The full conversion table is above.
Is it more accurate to enter inches than decimal feet?
Slightly, because you never round. The exact area of a 12 ft 7 in by 10 ft room is 125.8333 sq ft. Entering 12.58 instead of 12.5833 gives 125.80 sq ft — an error of 0.03 sq ft, or 0.026%. Irrelevant for a floor order, visible on a skirting list. The guide to measuring square footage with inches covers the same conversions in more depth.
Why does the answer always show two decimal places?
The main square-foot line is formatted to exactly two decimals with a thousands separator, so 120 reads as 120.00 and 10,000 as 10,000.00. The smaller conversion tiles strip trailing zeros instead, which is why 13.98 sq yd and 0.0029 acres look terser than the headline number. The math itself is never rounded — display only.
How do I add a waste factor for flooring or tile?
Open the "Waste factor and cost" panel and pick 0%, 5%, 10%, 15%, or type your own. A 10% factor on 120 sq ft means you should order 132 sq ft of material to cover cuts and breakage. The cost line is calculated on that adjusted area, so your price already includes the overage.
When should I use the full calculator instead?
Use the full calculator when a room has cutouts, alcoves, or multiple sections, or when it is not a rectangle — for example circles, triangles, trapezoids, L-shapes, or irregular polygons. It also draws a scaled preview and counts whole boxes from a coverage-per-box figure.
Does this calculator store my inputs anywhere?
No. The calculation runs entirely in your browser. Nothing is uploaded to a server, and the tool itself does not collect personal information. For details, see our privacy policy.
Sources and How to Check This Page
- The inch-to-foot and foot-to-meter values come from NIST Special Publication 811, Appendix B.9.1: 1 in = 2.54 cm exactly and 1 ft = 0.3048 m exactly. From those two definitions, 1 in = 1/12 ft = 0.08333… ft and 1 sq ft = 0.09290304 sq m.
- The foot used throughout this tool is the international foot fixed at 0.3048 m, not the US survey foot, per Federal Register 85 FR 62698 (survey foot deprecated as of December 31, 2022).
- Check the worked example yourself: 12 ft 7 in = 151 in; 151 ÷ 12 = 12.5833…; × 10 ft = 125.8333 sq ft; × 0.09290304 = 11.69 sq m; ÷ 9 = 13.98 sq yd; ÷ 43,560 = 0.0029 acre; × 144 = 18,120 sq in; × 1.10 = 138.42 sq ft with 10% waste.
- What this page does not claim: no combined feet-and-inches input box, no named or saved rooms, no perimeter, and no reverse solve from a known area. Waste percentages are the tool's preset examples, not manufacturer specifications.