# Imperial gallons to Liters (gal (UK) to L)

> Convert imperial gallons to liters: 1 gal (UK) = 4.54609 L. Exact conversion factor, formula, 22-row table and worked examples, with JSON API and MCP access.

- Page id: `imperial-gallons-to-liters` · Quantity: Volume (`volume`, base unit L) · Tool: `convert_units`
- Canonical page: https://tttkmbb.com/conversion/imperial-gallons-to-liters · This document: https://tttkmbb.com/conversion/imperial-gallons-to-liters.md · JSON: https://tttkmbb.com/conversion/imperial-gallons-to-liters.json (add `?value=` for a result)

## Formula

- `1 gal (UK) = 4.54609 L`
- `liters = imperial gallons × 4.54609`
- Reverse: `imperial gallons = liters × 0.2199692483`

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 gal (UK) = 22.7305 L
- 12.5 gal (UK) = 56.8261 L
- 100 gal (UK) = 454.609 L

## Conversion table

| Imperial gallons (gal (UK)) | Liters (L) |
| --- | --- |
| 1 | 4.54609 |
| 2 | 9.09218 |
| 3 | 13.6383 |
| 4 | 18.1844 |
| 5 | 22.7305 |
| 6 | 27.2765 |
| 7 | 31.8226 |
| 8 | 36.3687 |
| 9 | 40.9148 |
| 10 | 45.4609 |
| 15 | 68.1913 |
| 20 | 90.9218 |
| 25 | 113.652 |
| 30 | 136.383 |
| 40 | 181.844 |
| 50 | 227.305 |
| 75 | 340.957 |
| 100 | 454.609 |
| 200 | 909.218 |
| 250 | 1136.52 |
| 500 | 2273.05 |
| 1000 | 4546.09 |

## API

- `GET https://tttkmbb.com/api/v1/convert?value=5&from_unit=gal_uk&to_unit=L` → 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":"gal_uk","to_unit":"L"}`
- All volume units: https://tttkmbb.com/api/v1/units?quantity=volume · full converter: [Volume Converter](https://tttkmbb.com/conversion/volume.md)
- Authentication: none. Freshness: `static` (fixed conversion factors).

## FAQ

**How many liters are in one imperial gallon?**

1 gal (UK) = 4.54609 L. 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 imperial gallons to liters?**

Multiply the value in imperial gallons by 4.54609: liters = imperial gallons × 4.54609. For example, 5 gal (UK) = 22.7305 L.

**How do I convert liters back to imperial gallons?**

Multiply by the inverse factor 0.2199692483 (imperial gallons = liters × 0.2199692483), or use the liters-to-imperial gallons page.

## Related conversions

- [Liters to imperial gallons](https://tttkmbb.com/conversion/liters-to-imperial-gallons.md) (reverse)
- [Liters to US gallons](https://tttkmbb.com/conversion/liters-to-gallons.md)
- [US gallons to Liters](https://tttkmbb.com/conversion/gallons-to-liters.md)
- [Milliliters to US fluid ounces](https://tttkmbb.com/conversion/ml-to-fl-oz.md)
- [US fluid ounces to Milliliters](https://tttkmbb.com/conversion/fl-oz-to-ml.md)
- [Liters to Milliliters](https://tttkmbb.com/conversion/liters-to-ml.md)
- [Milliliters to Liters](https://tttkmbb.com/conversion/ml-to-liters.md)
- [US cups to Milliliters](https://tttkmbb.com/conversion/cups-to-ml.md)
- [Milliliters to US cups](https://tttkmbb.com/conversion/ml-to-cups.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)