# Kilowatt-hours to Megajoules (kWh to MJ)

> Convert kilowatt-hours to megajoules: 1 kWh = 3.6 MJ. Exact conversion factor, formula, 22-row table and worked examples, with JSON API and MCP access.

- Page id: `kwh-to-mj` · Quantity: Energy (`energy`, base unit J) · Tool: `convert_units`
- Canonical page: https://tttkmbb.com/conversion/kwh-to-mj · This document: https://tttkmbb.com/conversion/kwh-to-mj.md · JSON: https://tttkmbb.com/conversion/kwh-to-mj.json (add `?value=` for a result)

## Formula

- `1 kWh = 3.6 MJ`
- `megajoules = kilowatt-hours × 3.6`
- Reverse: `kilowatt-hours = megajoules × 0.2777777778`

The factor follows from the SI definitions of both units (NIST SP 811); values below are rounded to 6 significant figures, the API returns up to 12.

## Worked examples

- 5 kWh = 18 MJ
- 12.5 kWh = 45 MJ
- 100 kWh = 360 MJ

## Conversion table

| Kilowatt-hours (kWh) | Megajoules (MJ) |
| --- | --- |
| 1 | 3.6 |
| 2 | 7.2 |
| 3 | 10.8 |
| 4 | 14.4 |
| 5 | 18 |
| 6 | 21.6 |
| 7 | 25.2 |
| 8 | 28.8 |
| 9 | 32.4 |
| 10 | 36 |
| 15 | 54 |
| 20 | 72 |
| 25 | 90 |
| 30 | 108 |
| 40 | 144 |
| 50 | 180 |
| 75 | 270 |
| 100 | 360 |
| 200 | 720 |
| 250 | 900 |
| 500 | 1800 |
| 1000 | 3600 |

## API

- `GET https://tttkmbb.com/api/v1/convert?value=5&from_unit=kWh&to_unit=MJ` → unified JSON envelope with `result.values.result`, `formula`, `factor`, `sources`, `freshness`
- MCP: server `https://tttkmbb.com/mcp`, tool `convert_units` with `{"value":5,"from_unit":"kWh","to_unit":"MJ"}`
- All energy units: https://tttkmbb.com/api/v1/units?quantity=energy · full converter: [Energy Converter](https://tttkmbb.com/conversion/energy.md)
- Authentication: none. Freshness: `static` (fixed conversion factors).

## FAQ

**How many megajoules are in one kilowatt-hour?**

1 kWh = 3.6 MJ. The factor comes from the SI definitions of both units (NIST SP 811 / BIPM), so it is exact or correct to at least 10 significant figures.

**What is the formula to convert kilowatt-hours to megajoules?**

Multiply the value in kilowatt-hours by 3.6: megajoules = kilowatt-hours × 3.6. For example, 5 kWh = 18 MJ.

**How do I convert megajoules back to kilowatt-hours?**

Multiply by the inverse factor 0.2777777778 (kilowatt-hours = megajoules × 0.2777777778), or use the megajoules-to-kilowatt-hours page.

## Related conversions

- [Megajoules to kilowatt-hours](https://tttkmbb.com/conversion/mj-to-kwh.md) (reverse)
- [Kilocalories (food calories) to Kilojoules](https://tttkmbb.com/conversion/kcal-to-kj.md)
- [Kilojoules to Kilocalories (food calories)](https://tttkmbb.com/conversion/kj-to-kcal.md)
- [Joules to Calories (small, thermochemical)](https://tttkmbb.com/conversion/joules-to-calories.md)
- [Calories (small, thermochemical) to Joules](https://tttkmbb.com/conversion/calories-to-joules.md)
- [Kilowatt-hours to BTU](https://tttkmbb.com/conversion/kwh-to-btu.md)
- [BTU to Kilowatt-hours](https://tttkmbb.com/conversion/btu-to-kwh.md)
- [BTU to Joules](https://tttkmbb.com/conversion/btu-to-joules.md)
- [Joules to BTU](https://tttkmbb.com/conversion/joules-to-btu.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)