# Baseboard Trim Calculator

> Computes the room perimeter, subtracts door and other openings, adds a cutting-waste allowance and converts the length of baseboard (skirting) into stock pieces to buy, with the inside and outside corner count for a rectangular room and an optional cost.

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

## Purpose

Computes the room perimeter, subtracts door and other openings, adds a cutting-waste allowance and converts the length of baseboard (skirting) into stock pieces to buy, with the inside and outside corner count for a rectangular room and an optional cost.

**Use when:** You need to know how many lengths of baseboard, skirting board, shoe molding or quarter round to buy for a room.

**Do not use when:** You need the compound angles for crown molding (use crown-molding-miter) or the room is L-shaped: split it into rectangles and add one inside and one outside corner per notch.

## Input

| Parameter | Type | Unit | Required | Description |
| --- | --- | --- | --- | --- |
| `room_length` | number | m or ft | required | Room length in metres or feet (see unit). (> 0, max 1000) |
| `room_width` | number | m or ft | required | Room width in metres or feet. (> 0, max 1000) |
| `unit` | enum: m \| ft |  | optional, default "m" | Unit of the length inputs (m or ft). Lengths are reported in both units. |
| `doors` | integer |  | optional, default 1 | Number of door openings without baseboard. (min 0, max 50) |
| `door_width` | number | m or ft | optional | Width of each door opening; default 0.9 m (metric) or 3 ft (imperial). (> 0, max 10) |
| `other_openings_length` | number | m or ft | optional, default 0 | Total length of other gaps with no baseboard (built-in cabinets, fireplace, archways). (min 0, max 1000) |
| `trim_piece_length` | number | m or ft | optional | Length of the stock pieces you will buy; default 3.66 m (metric, a 12 ft length) or 12 ft (imperial). Common lengths: 2.4, 3, 3.66, 4.2 m; 8, 12, 16 ft. (> 0, max 20) |
| `waste_percent` | number | % | optional, default 10 | Extra material for cuts, breakage and offcuts, applied as a multiplier (1 + waste_percent/100). 10 % covers mitre cuts, scarf joints and damaged ends; use 15 % for rooms with many corners. (min 0, max 50) |
| `price_per_piece` | number |  | optional | Optional price of one stock piece; enables total_cost. (min 0) |

## Output

| Field | Type | Unit | Description |
| --- | --- | --- | --- |
| `perimeter_m` | number | m | 2 × (room_length + room_width). |
| `perimeter_ft` | number | ft | Perimeter in feet. |
| `trim_length_needed_m` | number | m | (perimeter − doors × door_width − other_openings_length) × (1 + waste_percent/100). |
| `trim_length_needed_ft` | number | ft | Same length in feet. |
| `pieces_to_buy` | integer |  | ceil(trim_length_needed / trim_piece_length). |
| `inside_corners` | integer |  | 4 for a rectangular room (cope or 45° inside mitre each). |
| `outside_corners` | integer |  | 0 for a rectangular room (add 1 inside + 1 outside per notch of an L-shape). |
| `total_cost` | number |  | pieces_to_buy × price_per_piece; only when a price is given. |

## Formula

`perimeter = 2 × (room_length + room_width); net = perimeter − doors × door_width − other_openings_length; trim_length_needed = net × (1 + waste_percent/100); pieces_to_buy = ceil(trim_length_needed / trim_piece_length); total_cost = pieces × price_per_piece.`

Plain perimeter take-off; the waste allowance covers 45° mitres at outside corners, coped inside corners and scarf joints on long walls (pieces at least as long as the longest wall avoid joints). Shoe molding or quarter round needs the same length again.

## Data Sources

- Wikipedia – Baseboard — https://en.wikipedia.org/wiki/Baseboard (reference, retrieved 2026-09-24)
- Wikipedia – Molding (decorative) — https://en.wikipedia.org/wiki/Molding_(decorative) (reference, retrieved 2026-09-24)

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/baseboard-trim?room_length=…&room_width=…`
- `POST https://tttkmbb.com/api/v1/calculate/baseboard-trim` 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/baseboard-trim · OpenAPI operationId `estimate_baseboard_trim` 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": "baseboard-trim", "inputs": {…}}`

## Example

- 5 m × 4 m room, one 0.9 m door, 3.66 m pieces, 10 % waste: inputs `{"room_length":5,"room_width":4,"unit":"m","doors":1,"door_width":0.9,"trim_piece_length":3.66,"waste_percent":10}` → `{"perimeter_m":18,"perimeter_ft":59.06,"trim_length_needed_m":18.81,"trim_length_needed_ft":61.71,"pieces_to_buy":6,"inside_corners":4,"outside_corners":0}`
- 14 ft × 12 ft room, two 3 ft doors, 12 ft pieces at $15, 10 % waste: inputs `{"room_length":14,"room_width":12,"unit":"ft","doors":2,"waste_percent":10,"price_per_piece":15}` → `{"perimeter_ft":52,"perimeter_m":15.85,"trim_length_needed_ft":50.6,"trim_length_needed_m":15.42,"pieces_to_buy":5,"total_cost":75}`

```
GET https://tttkmbb.com/api/v1/calculate/baseboard-trim?room_length=5&room_width=4&unit=m&doors=1&door_width=0.9&trim_piece_length=3.66&waste_percent=10
```

## Limitations

You need the compound angles for crown molding (use crown-molding-miter) or the room is L-shaped: split it into rectangles and add one inside and one outside corner per notch. Plain perimeter take-off; the waste allowance covers 45° mitres at outside corners, coped inside corners and scarf joints on long walls (pieces at least as long as the longest wall avoid joints). Shoe molding or quarter round needs the same length again. All values are computed from the formula above; no measurement or live data is involved.

## FAQ

**Should I subtract the door openings?**

Yes, baseboard stops at the door casing; each door removes its width (0.9 m / 3 ft typical). Windows do not matter because they are above the baseboard.

**Which piece length should I buy?**

Pieces longer than the longest wall avoid scarf joints: 4.2 m or 16 ft for a 4 m / 13 ft wall. Shorter pieces are cheaper to transport but each joint costs extra waste.

## Related

- [Crown Molding Miter Calculator](https://tttkmbb.com/construction/crown-molding-miter.md) — Saw angles for crown molding corners.
- [Paint Calculator](https://tttkmbb.com/construction/paint.md) — Paint for the walls above the baseboard.
- [Flooring Calculator](https://tttkmbb.com/construction/flooring.md) — Floor covering the baseboard will sit on.