# Board Feet Calculator

> Computes board feet (the US lumber volume unit: 1 board foot = 144 cubic inches = a 1 in × 12 in × 12 in board) from nominal thickness and width in inches and length in feet, for a given quantity, with the total cost at a price per board foot.

- Calculator id: `board-feet` · Category: Construction & Home (`construction`) · Tool name: `calculate_board_feet`
- Canonical page: https://tttkmbb.com/construction/board-feet · This document: https://tttkmbb.com/construction/board-feet.md · JSON definition: https://tttkmbb.com/construction/board-feet.json

## Purpose

Computes board feet (the US lumber volume unit: 1 board foot = 144 cubic inches = a 1 in × 12 in × 12 in board) from nominal thickness and width in inches and length in feet, for a given quantity, with the total cost at a price per board foot.

**Use when:** You are pricing or ordering hardwood or rough lumber sold by the board foot, or converting lumber dimensions into board feet, cubic feet or cubic metres.

**Do not use when:** Lumber is sold by the linear foot or piece (dimensional softwood such as 2 × 4 studs), or you need deck board counts (use decking).

## Input

| Parameter | Type | Unit | Required | Description |
| --- | --- | --- | --- | --- |
| `thickness_in` | number | in | required | Nominal thickness in inches (hardwood is often quoted in quarters: 4/4 = 1 in, 8/4 = 2 in). (> 0, max 48) |
| `width_in` | number | in | required | Nominal width in inches. (> 0, max 120) |
| `length_ft` | number | ft | required | Length in feet. (> 0, max 200) |
| `quantity` | integer |  | optional, default 1 | Number of identical pieces. (min 1, max 100000) |
| `price_per_board_foot` | number |  | optional | Optional unit price; enables the total cost. (min 0) |

## Output

| Field | Type | Unit | Description |
| --- | --- | --- | --- |
| `board_feet_each` | number | bd ft | thickness_in × width_in × length_ft / 12. |
| `board_feet_total` | number | bd ft | board_feet_each × quantity. |
| `total_cost` | number |  | board_feet_total × price_per_board_foot; only when a price is given. |
| `volume_cubic_feet` | number | ft³ | board_feet_total / 12. |
| `volume_m3` | number | m³ | Total volume in cubic metres (1 bd ft = 0.002359737 m³). |

## Formula

`board_feet = thickness_in × width_in × length_ft / 12 (equivalently T × W × L_in / 144); total = board_feet × quantity; cost = total × price_per_board_foot; ft³ = board_feet / 12; m³ = ft³ × 0.028316847.`

Board footage uses nominal (rough-sawn) dimensions: a surfaced 4/4 board that measures 13/16 in is still counted as 1 in thick. Some yards round each board's width to the nearest inch before calculating.

## Data Sources

- American Hardwood Export Council – Grading sawn lumber: measurement (board foot = W × L × D / 12) — https://www.americanhardwood.org/en/american-hardwood/grading-sawn-lumber/measurement (reference, retrieved 2026-09-23)
- NHLA – Rules for the Measurement & Inspection of Hardwood & Cypress (2023) — https://nhla.com/wp-content/uploads/2023/07/2023-Rulesbook_English_web.pdf (standard, retrieved 2026-09-23)
- Wikipedia – Board foot — https://en.wikipedia.org/wiki/Board_foot (reference, retrieved 2026-09-23)

Data freshness: `static`. Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output.

## API

- `GET https://tttkmbb.com/api/v1/calculate/board-feet?thickness_in=…&width_in=…&length_ft=…`
- `POST https://tttkmbb.com/api/v1/calculate/board-feet` with JSON body `{"inputs": {…}}`
- Response: unified envelope (`success`, `request`, `result.values`, `result.units`, `sources`, `freshness`, `timestamp`, `next_actions`, `links`); see https://tttkmbb.com/docs/response-format.md
- Schema: https://tttkmbb.com/api/v1/calculators/board-feet · OpenAPI operationId `calculate_board_feet` in https://tttkmbb.com/openapi.json
- Authentication: none. Rate limit: fair use, see https://tttkmbb.com/docs/rate-limits.md.

## MCP

- Server: `https://tttkmbb.com/mcp` (Streamable HTTP, JSON-RPC 2.0, no auth)
- Tool:  `run_calculator` with `{"calculator_id": "board-feet", "inputs": {…}}`

## Example

- Ten 1 × 6 boards, 8 ft long, at $5 per board foot: inputs `{"thickness_in":1,"width_in":6,"length_ft":8,"quantity":10,"price_per_board_foot":5}` → `{"board_feet_each":4,"board_feet_total":40,"total_cost":200,"volume_cubic_feet":3.3333,"volume_m3":0.09439}`
- One 2 × 4, 8 ft long: inputs `{"thickness_in":2,"width_in":4,"length_ft":8}` → `{"board_feet_each":5.333,"board_feet_total":5.333,"volume_cubic_feet":0.4444}`

```
GET https://tttkmbb.com/api/v1/calculate/board-feet?thickness_in=1&width_in=6&length_ft=8&quantity=10&price_per_board_foot=5
```

## Limitations

Lumber is sold by the linear foot or piece (dimensional softwood such as 2 × 4 studs), or you need deck board counts (use decking). Board footage uses nominal (rough-sawn) dimensions: a surfaced 4/4 board that measures 13/16 in is still counted as 1 in thick. Some yards round each board's width to the nearest inch before calculating. All values are computed from the formula above; no measurement or live data is involved.

## FAQ

**Do I use nominal or actual dimensions?**

Nominal. A 2 × 4 counts as 2 in × 4 in even though it measures 1.5 in × 3.5 in; hardwood thicknesses are quoted in quarters (5/4 = 1.25 in) of nominal thickness.

**How do I convert a length in inches?**

Divide by 12 to get feet, or use T × W × L(in) / 144, which gives the same board feet.

## Related

- [Decking Calculator](https://tttkmbb.com/construction/decking.md) — Board counts for a deck.
- [Volume Converter](https://tttkmbb.com/conversion/volume.md) — Convert cubic feet and cubic metres.
- [Rectangular Prism Calculator](https://tttkmbb.com/geometry/rectangular-prism.md) — General box volume.