# Torque Converter

> Converts torque (moment of force) between N·m, kN·m, N·cm, mN·m, lbf·ft, lbf·in, kgf·m, kgf·cm and ozf·in using exact force and length definitions (1 lbf·ft = 1.3558179483 N·m).

- Calculator id: `torque` · Category: Unit Conversion (`conversion`) · Tool name: `convert_torque`
- Canonical page: https://tttkmbb.com/conversion/torque · This document: https://tttkmbb.com/conversion/torque.md · JSON definition: https://tttkmbb.com/conversion/torque.json

## Purpose

Converts torque (moment of force) between N·m, kN·m, N·cm, mN·m, lbf·ft, lbf·in, kgf·m, kgf·cm and ozf·in using exact force and length definitions (1 lbf·ft = 1.3558179483 N·m).

**Use when:** You need a wrench, bolt or engine torque in another unit, e.g. lb-ft to N·m, N·m to lb-in or kgf·m to N·m.

**Do not use when:** You need energy in joules or foot-pounds of work (use energy; torque and energy share dimensions but are different quantities) or the force alone (use force).

## Input

| Parameter | Type | Unit | Required | Description |
| --- | --- | --- | --- | --- |
| `value` | number |  | required | Amount to convert, expressed in from_unit. |
| `from_unit` | enum: Nm \| kNm \| Ncm \| mNm \| lbf_ft \| lbf_in \| kgf_m \| kgf_cm \| ozf_in |  | required | Unit of the input value. Accepted symbols: Nm, kNm, Ncm, mNm, lbf_ft, lbf_in, kgf_m, kgf_cm, ozf_in; spelled-out names and common abbreviations are accepted too. |
| `to_unit` | enum: Nm \| kNm \| Ncm \| mNm \| lbf_ft \| lbf_in \| kgf_m \| kgf_cm \| ozf_in |  | required | Unit to convert into (same symbols as from_unit). |

## Output

| Field | Type | Unit | Description |
| --- | --- | --- | --- |
| `result` | number |  | Converted value expressed in to_unit (rounded to 6 decimals; see result_text for very small or very large values). |
| `result_text` | string |  | The conversion as text with 6 significant figures, e.g. "5 mi = 8.04672 km". |
| `formula` | string |  | Relation used, e.g. "1 mi = 1.609344 km". |
| `factor` | number |  | Multiplier from from_unit to to_unit (result = value × factor); absent for non-linear conversions. |
| `conversion_table` | object |  | The input value expressed in every supported torque unit (6 significant figures), keyed by unit symbol. |

## Formula

`result = value × factor, factor = (1 from_unit in Nm) / (1 to_unit in Nm)`

Torque = force × lever arm, so the factors are products of the force factors (lbf, kgf, ozf) and length factors (ft, in, m, cm).

## Data Sources

- NIST Special Publication 811 – Guide for the Use of the International System of Units (SI), Appendix B conversion factors — https://www.nist.gov/pml/special-publication-811 (standard, retrieved 2026-09-23)
- BIPM – The International System of Units (SI Brochure, 9th edition) — https://www.bipm.org/en/publications/si-brochure (standard, retrieved 2026-09-23)
- Wikipedia – Conversion of units — https://en.wikipedia.org/wiki/Conversion_of_units (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/torque?value=…&from_unit=…&to_unit=…`
- `POST https://tttkmbb.com/api/v1/calculate/torque` 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/torque · OpenAPI operationId `convert_torque` 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": "torque", "inputs": {…}}`

## Example

- 100 lb-ft to newton-metres: inputs `{"value":100,"from_unit":"lbf_ft","to_unit":"Nm"}` → `{"result":135.581795,"factor":1.3558179483,"formula":"1 lbf·ft = 1.355817948 N·m","conversion_table":{"kgf_m":13.8255,"lbf_in":1200}}`
- 250 N·m to lb-ft: inputs `{"value":250,"from_unit":"Nm","to_unit":"lbf_ft"}` → `{"result":184.390861,"conversion_table":{"kgf_m":25.4929,"lbf_in":2212.69}}`

```
GET https://tttkmbb.com/api/v1/calculate/torque?value=100&from_unit=lbf_ft&to_unit=Nm
```

## Limitations

You need energy in joules or foot-pounds of work (use energy; torque and energy share dimensions but are different quantities) or the force alone (use force). Torque = force × lever arm, so the factors are products of the force factors (lbf, kgf, ozf) and length factors (ft, in, m, cm). All values are computed from the formula above; no measurement or live data is involved.

## FAQ

**Is lb-ft the same as ft-lb?**

Both spellings denote the same torque unit (1 lbf·ft = 1.35582 N·m) and are accepted here. Foot-pound is also used for energy (ft·lbf in the energy converter); the numeric factor to joules is identical.

**How do I enter N·m?**

Use Nm (or N·m, N-m, newton metre); kgf·m is kgf_m and inch-pounds are lbf_in.

## Related

- [Force Converter](https://tttkmbb.com/conversion/force.md) — Force units behind each torque unit.
- [Energy Converter](https://tttkmbb.com/conversion/energy.md) — Same dimensions (N·m = J) but a different quantity.
- [Work & Power Calculator](https://tttkmbb.com/physics/work-power.md) — Work and power from force and motion.