FrameBOM

Wall framing takeoff

Support
Project framing defaults
Used by every wall that does not override. Override a specific wall in its own section below.
Format L*H OC-spacing CL CR — e.g. 12.5*3 OC625 CL CR: wall 12.5×3 m, 625 mm on-center, corner studs left (CL) and right (CR). In feet-inches: L*H in feet (3-6 = 3′6″ works), OC in inches (e.g. OC16). @ also works. Sloped wall: give two heights through a slash — 20*9/13 means 9 at the left end and 13 at the right. Stud lengths then vary along the wall and each one is listed separately in the parts list. Any profile: add intermediate vertices as offset:height — 20*8/10:14/8 is a gable peaking at 14 in the middle. Up to five intermediate points.
Framing parameters
Stud section: nominal — for the order & BOM; actual (for dry/planed lumber, e.g. 47*147) — for the geometry (stud length, member widths, header plies). Header section & ply count are auto-picked by span. Corner studs — CL/CR flags in the wall field. Section separator: *, x or ×. First stud offset — distance from the left edge to the first common stud (empty = one OC step); shifts the whole grid to land OSB seams on studs.
Format width*height/distance_to_opening_center_from_left. Height is the rough opening.
Format width*height/center or …/center/bottom. Optional 4th value — the window bottom-edge height (overrides the default). E.g. 2*2/8/0.6 — window sits lower. Leave empty if there are no windows.
Distances to interior-wall axes, comma-separated (e.g. 2.0, 8.125). If an axis lands on a stud — no ladder needed (marker ▲). Otherwise a ladder: horizontal blocking rungs between adjacent studs. No channels.
Heights of horizontal blocking rows, comma-separated (e.g. 1.2, 2.4). One block per stud bay at each height; opening voids are skipped.
OSB sheathing
Sheet size in the current unit (mm or ft — e.g. 1250*2500 or 4*8). Orientation sets how the sheet sits on the wall. The ◫ button toggles the seam grid on the drawing.
Formula · what and how it's calculated

Notation. s — spacing; t — board thickness (flat); stud length Ls = H − n·t, where n is the number of plate rows — 3 for a doubled top plate, 2 for a single one; hd — header depth (150 or 200 mm).

  1. Common studs: positions 0, s, 2s … ≤ L plus an end stud at L ⇒ N = ⌊L/s⌋ + 1 (+1 if L isn't a multiple of s). Studs clashing with an opening's framing are dropped (>2/3 overlap) or shifted to butt the king.
  2. Corners/ends: CL/CR flags in the wall field. Each corner = California detail: the end stud (50 face) + +1 backer turned flat (its depth face ~150 shows in the wall plane) — backing for the adjacent wall's sheathing, corner stays open for insulation.
  3. Per opening: 2 king studs full height Ls; trimmers (jack) — 1 or 2 per side (width > threshold), length = opening head height minus the bottom plate.
  4. Stud section: nominal (e.g. 50×150) — order/BOM & volume; actual (e.g. 47×147) — geometry: face thickness sets Ls = H − n·thickness, member widths and bearings; depth sets header ply count.
  5. Header (auto): built up across the wall depth — plies = round(depth / thickness). Section by span w: ≤ 1.5 m — nominal; wider — one size deeper (span > 2.7 m — warning, needs LVL/beam). Ply length w + 2·thickness (bearing on trimmers).
  6. Header placement (global): over opening — header at the opening head, cripples fill above it to the top plate; optional top sill (header bears on it). under top plate — header tight to the top plate (all heads on one level), a top sill at the opening head, cripples between sill and header.
  7. Cripples: ⌊w/s⌋ + 1; length = the clear gap of that mode. For a window also under-sill: ⌊w/s⌋ + 1, length bottom − t, plus a sill board w.
  8. Plates: 3 · L (bottom + double top), cut from available lengths with joints over studs.
  9. Partition tees (T, ladder): each axis is checked against a full-height member (common/king/corner) within ±30 mm. If it lands on one — on-stud, no extra material. Otherwise a ladder: horizontal blocking between adjacent studs, count ⌊Ls / ladder_spacing⌋ + 1.
  10. Order: all parts of a section are packed into available board lengths (best-fit decreasing) minimizing waste; deeper headers are a separate section.

This is the bare wall-plane frame. Not included: OSB sheathing, fasteners, bracing, T-node blocking — separate BOM sections.

What FrameBOM does

FrameBOM is a free wall framing takeoff calculator for platform-framed timber walls. Describe a wall the way you would on site — length, height, on-center spacing, which ends are corners — add its door and window openings, and it returns the complete framing member list with an elevation drawing and a cut list optimized against the board lengths you can actually buy.

It is aimed at framers, small builders, frame shops and self-builders who need a lumber bill of materials in seconds rather than a full BIM model. Every member the wall needs is counted: common studs, king studs, jack studs (trimmers), cripples above and below openings, headers sized by span, sills, California corners, partition-tee ladders, horizontal blocking rows, bottom and double top plates, and OSB or plywood sheathing.

Both metric and imperial are supported at project level — millimetres and metres, or feet and inches with sixteenths. The interface is available in English and Ukrainian. Nothing is uploaded: the whole calculation runs in your browser, every project is saved in the page URL so you can share it as a plain link, and the app keeps working with no connection at all once it has been opened.

Wall framing glossary
Common stud
A regular vertical member repeating at the on-center spacing, carrying the wall between the bottom plate and the top plate.
On-center (OC) spacing
The distance from the center of one stud to the center of the next — typically 16 in or 24 in, 400 mm or 625 mm.
King stud
The full-height stud running alongside an opening, from bottom plate to top plate, to which the header assembly is fixed.
Jack stud (trimmer)
A shortened stud nailed to the king stud that carries the header. Wide openings take doubled trimmers on each side.
Cripple stud
A short stud filling the gap above a header or below a window sill, keeping the stud grid continuous for sheathing.
Header
The beam spanning an opening and transferring load to the jack studs. Its depth and number of plies follow the span.
Sill
The horizontal member forming the bottom of a window opening, supported by the cripples beneath it.
Bottom and top plate
The horizontal members closing the wall. Platform framing normally uses a single bottom plate and a doubled top plate, so stud length is wall height minus three plate thicknesses. FrameBOM can also model a single top plate, which makes it two.
California corner
A corner detail using an end stud plus a backer turned flat. It gives the adjacent wall's sheathing something to land on while leaving the corner cavity open for insulation.
Partition tee (ladder)
Where an interior wall meets this one. If its axis lands on an existing stud no extra material is needed; otherwise short horizontal blocking rungs form a ladder between adjacent studs.
Blocking
Horizontal members between studs at a given height, used for fire blocking, bracing, or backing for fixtures.
Sheathing
OSB or plywood panels closing the wall plane. FrameBOM counts sheets by grid, either as full sheets or with openings deducted.
Takeoff
The count of materials read off a drawing or specification — the input to a bill of materials and a purchase order.
Cut list
Which pieces to cut from which purchased board, arranged to minimize offcut waste.
Questions

Is FrameBOM free?

Yes. The calculator is free to use, needs no account, and runs entirely in your browser.

Does it work offline?

Yes. Once the page has been opened once it is cached, so it keeps working with no connection. You can also install it as an app from your browser's menu, or with the Install button in the header.

Where are my projects stored?

In two places, both of them yours: the page URL, and your browser's local storage. Nothing is sent to a server. Copying the link copies the entire project, so you can share a wall with someone by pasting a link into a message.

Can I use feet and inches?

Yes. Units are set for the whole project and can be switched at any time — metric in millimetres and metres, or imperial in feet and inches down to sixteenths. Existing values are converted, not retyped.

How does it size headers?

Header depth and ply count are chosen automatically from the opening span. You can place the header directly over the opening or tight under the top plate, and optionally add an upper sill.

Does it handle multiple walls in one project?

Yes. Walls are added as tabs and share the project framing defaults, and any wall can override those defaults for itself. A summary view totals the material across every wall.

How is the cut list calculated?

Pieces are packed into your available stock lengths with a best-fit-decreasing heuristic, cutting from longer to shorter and allowing for saw kerf, so the waste percentage reflects boards you would actually buy.

Which framing standard does it follow?

Platform framing as built in North America and in European timber-frame practice, with the opening detail selectable so both header conventions are available. It is an estimating aid — verify results against your local code and drawings before ordering.

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Frame-takeoff · 50×150 platform · default OC 625 mm · offline, data stays local. Parameters are saved in the link (permalink) and locally in the browser.