Most walls are framed with studs at 16 in on centre (24 in for some exterior walls under advanced framing). Each door or window needs king and jack studs plus cripples, and each corner or wall intersection needs extra studs for backing. Walls normally have a single bottom plate and a double top plate.
How to use the Framing Calculator
- Wall length
- Wall height (finished framing)
- Stud spacing
- Door and window openings
- Corners and intersections
- Plates
- Waste
- Price per stud
- Plate lumber price
Results update as you type, and every field accepts the units shown in its menu.
How it works
Enter the wall length and height, the stud spacing, the number of openings and corners, the number of plates and waste. The calculator counts the common studs, adds extra studs for openings and corners, works out the total length of plates and the stud cut length, and prices it all.
Tips for an accurate estimate
- Sketch the job and split irregular areas into rectangles, circles and triangles before you measure.
- Add a waste allowance – typically 5–10% for simple layouts and 15–20% for diagonal, curved or heavily cut work.
- Check the coverage or yield printed on the product, because sizes and densities vary between manufacturers.
- Buy all units of a finished material (tile, brick, siding) from the same batch so colours match, and keep a few spares for repairs.
- Confirm local prices – quarry, lumber and steel prices vary widely by region and season.
Common mistakes to avoid
- Ordering exactly the calculated amount with no allowance for breakage, offcuts and settlement.
- Forgetting to subtract doors, windows and other openings – or subtracting small ones that still need cutting around.
- Confusing US short tons (2,000 lb) with metric tonnes (1,000 kg) when comparing quotes.
Inputs explained
| Field | What to enter |
|---|---|
| Wall length | Units: ft, m, in, yd, cm |
| Wall height (finished framing) | Units: ft, m, in, yd, cm |
| Stud spacing | Choose one: 12 in o.c., 16 in o.c., 19.2 in o.c., 24 in o.c. … |
| Door and window openings | A number |
| Corners and intersections | A number |
| Plates | Choose one: Single bottom + double top (3), Single bottom + single top (2) |
| Waste | In % |
| Price per stud | Units: /piece |
| Plate lumber price | Units: /ft, /m, /yd |
What each result means
- Common studs = ceil([Wall length]÷[Stud spacing] – 0.000001) + 1
- Total studs = ceil(([Common studs] + 3×[Door and window openings] + 2×[Corners and intersections])×(1 + [Waste]÷100))
- Plate length = [Wall length]×[Plates]×(1 + [Waste]÷100)
- Stud cut length = [Wall height (finished framing)] – [Plates]×0.0381
- Material cost = [Total studs]×[Price per stud] + [Plate length]×[Plate lumber price]
Example values
How the main result changes when Wall length changes and everything else stays at the example values above:
| Wall length (ft) | Total studs |
|---|---|
| 10 | 18 |
| 15 | 22 |
| 20 | 26 |
| 25 | 30 |
| 30 | 35 |
| 40 | 42 |
Formula
Studs = (ceil(L ÷ spacing) + 1 + 3 × openings + 2 × corners) × (1 + waste)Plates = wall length × number of platesStud length = wall height − plates × 1½ inWorked example
Inputs — Wall length: 20 ft; Wall height (finished framing): 8 ft; Stud spacing: 16 in o.c.; Door and window openings: 1; Corners and intersections: 2; Plates: Single bottom + double top (3); Waste: 10 %; Price per stud: $4.5 /piece; Plate lumber price: $0.7 /ft.
Results — Common studs = 16; Total studs = 26; Plate length = 66 ft; Stud cut length = 91.5 in; Material cost = $163.20.
Key terms
- On centre (o.c.)
- Distance from the centre of one stud to the centre of the next.
- King stud
- Full-height stud beside an opening; the jack stud next to it supports the header.
Frequently asked questions
How many studs do I need for a 20 ft wall?
At 16 in on centre: 20 × 12 ÷ 16 + 1 = 16 common studs, plus about 3 per opening and 2 per corner.
What is a precut stud?
A stud cut to 92⅝ in so that with a bottom plate and double top plate the wall is 97⅛ in tall – right for 8 ft drywall plus a ceiling.
Why add studs for openings?
Each door or window needs king studs, jack (trimmer) studs and often cripples above and below.
What formula does the Framing Calculator use?
Studs = (ceil(L ÷ spacing) + 1 + 3 × openings + 2 × corners) × (1 + waste).