Lumber Calculator
Studs, plates and sheathing for a framed wall — counted by the on-center law, wasted honestly, priced in boards.
Lumber Calculator
Results recalculate instantly on every keystroke. Nothing you type is transmitted.
What this result does not account for
- One straight wall per computation.
- Openings, corners and headers enter as your separate line.
- Ceiling and roof framing are different pages of the drawing.
In short: A 16-ft wall at 8 ft, 16-in o.c.: 13 studs → 15 ordered at 15%, plates 48 lf (three 16-ft boards), sheathing 5 sheets — 152 lf of framing lineal.
Formula
studs = ⌈L × 12 ÷ spacing⌉ + 1
plates = 3 × L (bottom + doubled top)
sheathing = ⌈L × H × 1.10 ÷ 32⌉
lineal = studs × H + plates
[('+1', 'the run’s end stud — the classic short order'), ('3×', 'one bottom plate, a doubled top'), ('1.10', 'sheathing’s cutting waste, inside the ceil'), ('elevation work', 'corners, kings, trimmers, headers — yours to add')]
Worked Example
- Line the studs: length over spacing, plus the end stud.
- Waste the line into an order.
- Plate it: three lineal feet per foot of wall.
- Skin it: sheets at 32 ft² and a tenth.
- Add the elevation lines this page refuses to invent.
The 16-ft wall at 8 ft, 16-in o.c.: 13 studs in the line → 15 ordered at 15%; plates 48 lf = 3 boards; sheathing 5 sheets; 152 lf of framing; $124.50 at $5.50 studs and $14 plates.
Strengths & Limits Of This Model
Where this engine is strong
- End stud and plate doubling counted, not forgotten
- Lineal total for real stock orders
- Honest about what elevations must add
Where it stops
- No opening take-off
- Single wall runs only
Practical Use Cases
Partition walls
Basement and room-dividing runs.
Shed and garage lines
Whole frames from wall lengths.
Stock orders
Lineal feet for the yard call.
Sheathing counts
Skin before the siding quote.
Framing quotes
Studs priced apart from openings.
Methodology & Editorial Standards
Studs ceiling the line at the entered on-center spacing and add the end stud; waste ceils the order. Plates are exactly 3× wall length, priced in whole 16-ft boards. Sheathing ceils area × 1.10 over the 32-ft² sheet. Corners and openings are deliberately NOT invented — the page says so where the numbers are. Spacing outside 12-48 in is refused.
Computation runs in IEEE-754 double precision at full internal precision; rounding to two decimal places occurs strictly at the display layer, so no cumulative drift enters the result. All monetary outputs use accounting presentation — grouped thousands, two decimals, negatives in parentheses — so figures can be transcribed directly into a model or working paper. Division-by-zero and out-of-domain inputs return an em-dash rather than a misleading number.
This engine was reconciled against an independent reference implementation and hand-verified for the worked example above before release. Our full five-stage review process is published on the About Us page.
Disclaimer. This calculator is provided for informational and modelling purposes only and does not constitute financial, tax, legal, medical, or engineering advice. Verify all figures with a qualified professional before acting on them.
Lumber Calculator — 10 Expert FAQs
10 analyst-written answers to the questions practitioners actually ask — optimised for voice and answer-engine retrieval.
How many studs do I need for a 16-foot wall?
⌈16 × 12 ÷ 16⌉ + 1 = 13 in the line; 15% framing waste orders 15. Corners, doors and windows add their own kings, trimmers and cripples on top — count them from the elevation.
Why is the top plate doubled?
Two plates tie intersecting walls together, spread joist and rafter loads across the studs, and give nails a second chance across every seam. The bottom stays single on slab; doubled where floors cross.
16 or 24 inches on center?
16 for anything structural, anything carrying drywall vertically, and most exterior walls; 24 for non-bearing partitions under ⅝-in drywall, where the span tables allow it. The savings in studs is real; the flex is too.
How much waste should framing carry?
Ten percent on straight runs of pre-cuts; 15% is the working default once plates, blocking and offcuts arrive; 20% on complicated frames. Studs are cheap; a second yard trip is not.
How much lumber is a lineal foot of wall?
A 16-in o.c. wall runs roughly 9-10 lf of stud per wall-foot at 8 ft, plus 3 lf of plate — call it a dozen lineal feet per foot of wall before openings. This page prints the exact figure for your height.
Does this include headers over doors and windows?
No — headers double up by opening width, kings and trimmers flank them, and cripples fill above and below. That work lives on the elevation drawing; this page prices the line, the plates and the skin.
How many sheets of sheathing for my wall?
Wall area × 1.10 ÷ 32, ceiled: the 16 × 8 wall takes 5 sheets. The tenth covers seams, corners and the sheets that lose an argument to the saw.
Are precut studs worth it?
92⅝-in precuts save a cut per stud on 8-ft walls and keep the offcut pile honest — the count does not change, the saw time does. Price both ways at your yard.
What spacing do rafters and joists want from me?
None here — this page counts a wall. Floors and roofs frame on their own spans and tables, which is exactly the kind of thing to get from the drawing, not a calculator.
Pressure-treated where?
Anywhere wood meets masonry or weather: bottom plates on slab, sills, and anything within inches of grade. The count does not change; the SKU does — and it prices higher per board.