# Degrees Fahrenheit to Degrees Celsius (°F to °C)

> Convert degrees Fahrenheit to degrees Celsius with the formula °C = (°F − 32) × 5/9. Conversion table and worked examples, with JSON API and MCP access.

- Page id: `fahrenheit-to-celsius` · Quantity: Temperature (`temperature`, base unit K) · Tool: `convert_units`
- Canonical page: https://tttkmbb.com/conversion/fahrenheit-to-celsius · This document: https://tttkmbb.com/conversion/fahrenheit-to-celsius.md · JSON: https://tttkmbb.com/conversion/fahrenheit-to-celsius.json (add `?value=` for a result)

## Formula

- `°C = (°F − 32) × 5/9`
- `°C = (°F − 32) × 5/9`
- Reverse: `°F = °C × 9/5 + 32`

Non-linear conversion: apply the formula directly; there is no single multiplication factor.

## Worked examples

- 37 °F = 2.77778 °C
- 100 °F = 37.7778 °C
- -40 °F = -40 °C

## Conversion table

| Degrees Fahrenheit (°F) | Degrees Celsius (°C) |
| --- | --- |
| -40 | -40 |
| -30 | -34.4444 |
| -20 | -28.8889 |
| -10 | -23.3333 |
| 0 | -17.7778 |
| 5 | -15 |
| 10 | -12.2222 |
| 15 | -9.44444 |
| 20 | -6.66667 |
| 25 | -3.88889 |
| 30 | -1.11111 |
| 35 | 1.66667 |
| 37 | 2.77778 |
| 40 | 4.44444 |
| 50 | 10 |
| 60 | 15.5556 |
| 70 | 21.1111 |
| 80 | 26.6667 |
| 90 | 32.2222 |
| 100 | 37.7778 |
| 150 | 65.5556 |
| 200 | 93.3333 |

## API

- `GET https://tttkmbb.com/api/v1/convert?value=37&from_unit=F&to_unit=C` → unified JSON envelope with `result.values.result`, `formula`, `factor`, `sources`, `freshness`
- MCP: server `https://tttkmbb.com/mcp`, tool `convert_units` with `{"value":37,"from_unit":"F","to_unit":"C"}`
- All temperature units: https://tttkmbb.com/api/v1/units?quantity=temperature · full converter: [Temperature Converter](https://tttkmbb.com/conversion/temperature.md)
- Authentication: none. Freshness: `static` (fixed conversion factors).

## FAQ

**What is the formula to convert degrees Fahrenheit to degrees Celsius?**

°C = (°F − 32) × 5/9. For example, 37 °F = 2.77778 °C.

**How do I convert degrees Celsius back to degrees Fahrenheit?**

°F = °C × 9/5 + 32; the degrees Celsius-to-degrees Fahrenheit page applies it directly.

**Why is there no single multiplication factor?**

Temperature scales have different zero points, so the conversion is an affine formula (scale and offset), not a plain multiplication.

## Related conversions

- [Degrees Celsius to degrees Fahrenheit](https://tttkmbb.com/conversion/celsius-to-fahrenheit.md) (reverse)
- [Degrees Celsius to Kelvin](https://tttkmbb.com/conversion/celsius-to-kelvin.md)
- [Kelvin to Degrees Celsius](https://tttkmbb.com/conversion/kelvin-to-celsius.md)
- [Degrees Fahrenheit to Kelvin](https://tttkmbb.com/conversion/fahrenheit-to-kelvin.md)
- [Kelvin to Degrees Fahrenheit](https://tttkmbb.com/conversion/kelvin-to-fahrenheit.md)
- [Degrees Fahrenheit to Degrees Rankine](https://tttkmbb.com/conversion/fahrenheit-to-rankine.md)
- [Degrees Rankine to Degrees Fahrenheit](https://tttkmbb.com/conversion/rankine-to-fahrenheit.md)
- [Kelvin to Degrees Rankine](https://tttkmbb.com/conversion/kelvin-to-rankine.md)
- [Degrees Rankine to Kelvin](https://tttkmbb.com/conversion/rankine-to-kelvin.md)

## 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 2026-09-24)
- BIPM – The International System of Units (SI Brochure, 9th edition) — https://www.bipm.org/en/publications/si-brochure (standard, retrieved 2026-09-24)
- Wikipedia – Conversion of units — https://en.wikipedia.org/wiki/Conversion_of_units (reference, retrieved 2026-09-24)