Fluid Volume Converter
Convert engine and transmission fluid volumes between litres, US gallons, UK gallons, and quarts — for any fill or drain job.
Fluid Volume Converter
L ⇄ US gal ⇄ UK gal ⇄ qt
How It Works
Volume conversions use exact defined values. 1 US gallon = 3.785 41 L exactly. 1 UK gallon = 4.546 09 L. These differ because UK and US gallons are different sizes.
How to Use This Calculator
- Enter the fluid volume in any one field.
- Click Convert to see all four unit equivalents.
- Check the spec — US workshop manuals use quarts; European manuals use litres.
- Use UK gallons for British/Australian manuals that predate metric conversion.
- Always buy slightly more than the spec to allow for filter pre-fill.
Worked Example
Reference Table
| Fluid Spec | Litres | US Quarts | US Gallons |
|---|---|---|---|
| Engine oil (4-cyl) | 3.5–4.5 L | 3.7–4.8 qt | 0.92–1.19 gal |
| Engine oil (6-cyl) | 5.0–6.5 L | 5.3–6.9 qt | 1.32–1.72 gal |
| Coolant system | 5–9 L | 5.3–9.5 qt | 1.32–2.38 gal |
| Auto transmission | 7–10 L | 7.4–10.6 qt | 1.85–2.64 gal |
| Manual gearbox | 1.5–2.5 L | 1.6–2.6 qt | 0.40–0.66 gal |
| Power steering | 0.5–1.0 L | 0.5–1.1 qt | 0.13–0.26 gal |
Frequently Asked Questions
Why is a US quart less than a litre?
A US liquid quart is 0.946 L — slightly less than a litre. This causes confusion when buying oil in quart containers for a car specced in litres. A 5-quart jug holds only 4.73 L, not 5 L.
Why are US and UK gallons different sizes?
The UK imperial gallon was originally defined as the volume of 10 pounds of water. The US gallon was redefined from a different historical measure (the Queen Anne wine gallon). They diverged in the 18th century and were never reconciled.
How do I read a fluid spec that says 5W-30, 4.5 US qt — do I buy two quart bottles?
Yes — two 1-quart bottles = 1.892 L, which is under spec. Buy two 1-quart bottles and one additional bottle; use the 4.5 qt mark on the dipstick as your fill target.
Does it matter if I use a little more or less than the spec for engine oil?
Engine oil capacity has a min/max range shown on the dipstick. Operating between min and max is fine. Overfilling by more than 0.5–1 L can cause oil foaming, crankcase pressure, and seal damage.
