How many litres is my reserve tank?
There isn’t a universal litres figure for a reserve tank—it's vehicle-specific. Check your vehicle’s official specs or owner’s manual to know the exact reserve volume; if unavailable, you can estimate with a careful fill-and-measure method described below.
What does the reserve refer to on different vehicles
In most modern cars, there isn't a separate reserve tank. The fuel gauge shows remaining usable fuel and a low-fuel warning comes once the stored fuel falls to a small margin above empty. Some motorcycles and older vehicles, however, define a reserve portion of the tank that remains after you switch to reserve mode; the exact liters vary by model. Knowing how your vehicle defines reserve helps you plan refueling and avoid being stranded.
How to determine your reserve capacity
This set of steps shows how to find the official reserve figure or to estimate it when the manual doesn’t provide a direct number.
- Consult the owner’s manual, the manufacturer’s website, or the data plate inside the fuel filler door for the tank’s total capacity and the usable fuel specification; reserve volume is often listed separately or implied by the usable fuel figure.
- If the explicit reserve figure is listed, use that value as your reserve volume. If only total capacity and usable fuel are given, the reserve is the difference between total capacity and usable fuel, noting that “usable” is what you can reliably use under normal conditions.
- Look for any tank or fuel-system specifications in the service booklet or warranty literature, which sometimes include the reserve range or the amount left when the warning comes on.
- If official data isn’t available, perform a controlled measurement: fill the tank to full, reset trip/odometer, then drive until the low-fuel warning triggers or the gauge nears empty. Refill to full and record the liters added. The amount you added equals usable fuel; the reserve portion is whatever remains in the tank beyond typical range before you reach empty—this will vary by vehicle and fuel gauge calibration.
- For motorcycles or dual-tank setups, check the specific operator’s manual for the reserve specification, as many bikes designate a fixed reserve volume (often a few liters) to allow a margin after the main supply is exhausted.
Note that reserve capacity is not standardized across brands or models. Use the official specification whenever possible, and treat any estimates as guides for planning rather than exact figures.
Summary
The exact litres of a reserve tank depend on the vehicle. There is no universal answer. By consulting the manual, checking the manufacturer’s specs, or performing a careful fill-and-measure test, you can determine or estimate your reserve volume and plan refueling accordingly.
