Stud calculator

Enter the wall length and stud spacing to see how many studs and plate boards to buy.

By the Calcist team · Checked against known answers · Updated October 27, 2026

Private: calculated on your device. Nothing you type is sent anywhere.

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How many studs per wall?

Divide the wall length in inches by the spacing, round up, and add one for the end of the wall. Then add studs for corners and for the king and jack studs around doors and windows.

Studs = wall length (in) ÷ spacing, rounded up, + 1
+ 2 per corner + 2 per door or window
Plates = 3 × wall length (one bottom plate, two top plates)

Worked example

A 20 ft wall at 16 in on center: 240 ÷ 16 = 15, + 1 = 16 studs. With 2 corners (+4) and one window (+2) that's 22. Adding 10% for warped or split boards gives 24.2, so buy 25 studs. The plates need 60 ft of lumber, which is 8 boards of 8 ft.

A quick rule of thumb

At 16 inches on center, many builders estimate one stud per foot of wall. It's close for walls with a few openings, because the extra king and jack studs roughly make up the difference.

Limitations

Openings vary: a wide opening needs a header and cripple studs. The +2 per opening is an estimate.
Code and loads: spacing, stud size and headers for load-bearing walls must follow your local building code.
Blocking and backing for cabinets, fire blocking and nailers aren't included.

Sources

International Residential Code 2021, Chapter 6: Wall construction

How we checked this

Before every update, this calculator is run in a real browser with these known answers, and it must match all of them:

20 ft wall at 16 in, 2 corners, 1 opening, 10%: 25 studs ✓
Same: plates need 8 boards of 8 ft ✓
20 ft wall at 24 in, no extras: 11 studs ✓
Edge: 1 ft wall at 16 in is 2 studs ✓

Last checked October 26, 2026. Spotted something wrong? The math is done in your browser with the formula shown on this page, so you can check any result by hand.

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Questions people ask

How many studs do I need for a 10 foot wall?

At 16 in on center: 120 ÷ 16 = 7.5, rounded up to 8, + 1 = 9 studs, before corners, openings and extra.

How many studs for a 12 foot wall?

At 16 in on center, 144 ÷ 16 = 9, + 1 = 10 studs. At 24 in on center, 7.

Are studs 16 or 24 inches apart?

16 inches on center is most common for houses. 24 inches is allowed for many non-load-bearing and some load-bearing walls under the IRC.

Why add one stud?

Spacing counts the gaps between studs. A wall with 15 gaps has 16 studs, counting the one at the end.

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