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Stud Calculator
Use this free stud calculator to find out how many studs a framed wall needs. Enter the wall length, pick 16-inch or 24-inch spacing, count the doors and windows, and add the corners. The calculator gives you the stud count using the standard framing rule, plus the bottom plate and top plate lumber to order.
How it works
A framed wall is built from vertical studs held between a bottom plate and a top plate, and the stud count follows a simple rule. Convert the wall length to inches, divide by the stud spacing, and add one stud for the end of the wall. A 24-foot wall with studs 16 inches on center needs (24 × 12 ÷ 16) + 1 = 19 studs before anything else is added, because the first stud sits at the very start of the wall and the rest are spaced out from there.
Every opening needs extra studs. A door or a window interrupts the regular spacing, so it gets two extra studs: one king stud that runs full height beside the opening and one jack stud that supports the header above it. The calculator adds 2 studs for every door and every window you enter. A wall with 2 doors and 3 windows gets 10 extra studs on top of the regular count, which is why openings are the biggest driver of the total after the wall length itself.
Corners need one extra stud each. Where two walls meet at a corner, an extra stud gives the drywall on the inside corner something to fasten to, and it ties the two walls together. A freestanding wall has no corners, a wall that meets another wall at one end has one, and a normal room wall usually has two. Enter the number of corners and the calculator adds one stud per corner.
Plates are the horizontal lumber top and bottom. The bottom plate is one length of the wall, and the top plate is usually doubled: two lengths stacked on top of each other, with the joints staggered so the wall is tied together along its length. That means the total plate lumber is three times the wall length with a double top plate, or twice the wall length with a single top plate. The calculator shows the bottom plate, the top plate, and the total separately so you can order the right lengths.
Spacing is the other choice that changes the count. Sixteen inches on center is the standard for load-bearing walls and for walls that will carry tile or heavy cabinets, because it gives a stiffer wall and more fastening points for drywall. Twenty-four inches on center uses fewer studs and is allowed for some non-load-bearing interior walls, but it can feel less solid and some finishes need closer spacing. Check your local code before choosing 24-inch spacing on an exterior or load-bearing wall. Buy a few extra studs beyond the count, since lumber is never perfectly straight and a warped stud should be set aside, not forced into the wall.
Worked example
A partition wall is 24 feet long, with studs 16 inches on center, 2 doors, 3 windows, and 2 corners, built with a double top plate.
Step 1: Find the regular studs — 24 × 12 = 288 inches, 288 ÷ 16 = 18, plus 1 for the end stud = 19 studs.
Step 2: Add the openings — 2 doors + 3 windows = 5 openings, 5 × 2 = 10 extra studs.
Step 3: Add the corners — 2 corners × 1 = 2 extra studs.
Step 4: Total studs — 19 + 10 + 2 = 31 studs.
Step 5: Find the plates — bottom plate 24 ft, double top plate 2 × 24 = 48 ft, total 24 + 48 = 72 ft of plate lumber.
The wall needs 31 studs and 72 feet of plate lumber. In practice that is three 8-foot studs cut for the plates plus the 31 full-length studs, so order 31 studs and 9 pieces of 8-foot lumber for the plates, with a couple of spare studs for warped pieces.
FAQ
How many studs do I need for a wall?
Divide the wall length in inches by the stud spacing, add 1 for the end stud, then add 2 studs per door or window and 1 stud per corner. A 24-foot wall at 16-inch spacing with 5 openings and 2 corners needs 31 studs. The calculator does this for you.
Should studs be 16 or 24 inches apart?
Sixteen inches on center is the standard for load-bearing and exterior walls and for walls carrying tile or cabinets. Twenty-four inches is allowed for some non-load-bearing interior walls and uses fewer studs, but check your local code first, since it is not permitted everywhere.
Why does each window or door add 2 studs?
An opening interrupts the regular stud spacing, so it needs a king stud running full height beside it and a jack stud supporting the header above it. That is 2 extra studs per opening, one on each side in practice, and the calculator adds them automatically.
How much lumber do I need for the top and bottom plates?
The bottom plate is one wall length and the top plate is usually doubled, so two more wall lengths, giving three wall lengths in total. A 24-foot wall needs 72 feet of plate lumber with a double top plate, or 48 feet with a single top plate.
How long should wall studs be?
For an 8-foot ceiling, studs are usually cut to 92 5/8 inches, which plus the bottom plate and double top plate gives a finished wall height of 97 1/8 inches, allowing for the floor and drywall. The calculator counts studs; cut them to the height your ceiling and plates require.