Fuel economy log
Calculate consumption across full and partial fill-ups, with complete intervals and pending fills kept separate.
The first full tank establishes the baseline. Its purchase and earlier records are exported but excluded from consumption. Every later full tank closes an interval that includes all intervening partial fills and the closing fill. Trailing partials remain pending. Full-tank levels must be comparable; missing fills and odometer rollover/replacement invalidate the model. Reports normalize to km and litres and calculate weighted complete-interval consumption. Costs are purchases, not the value of fuel consumed. Download to keep your log: this tool does not automatically save data between sessions or store receipts. Processing stays on your device in a cancellable worker with a 10-second timeout. Maximum 500000 combined input characters and 2000 records, with 30 tariffs or grades, 30 tiers per tariff and 100 depreciation years. Guided decimals allow up to six places without thousands separators. Full JSON and JSON Pointer CSV include all source inputs, units, assumptions and results; each file is capped at 2000000 characters and CSV at 200000 leaf records. All tariff totals precede the first 200 detail rows in the parking preview; other tables preview 200 rows. Software bounds are not vehicle capability claims. Results use floating-point arithmetic. Up to 500,000 characters. Review the settings before running.
Your result
How to use Fuel economy log
- Choose odometer and fuel units, then enter fill-up CSV with dates, fuel amounts, cost and fullTank true or false.
- Mark comparable full tanks accurately and keep all partial fills in date and odometer order.
- Review completed-interval consumption and pending fills. Download the full log to keep your records.
Useful next steps
Handle partial tanks without guessing consumption
The first full tank establishes a baseline. Every later full tank closes an interval that includes all intervening partial fills and the closing fill. Earlier purchases and the baseline fill remain in the export but are excluded from interval fuel totals. Trailing partials remain pending.
Keep a complete, consistent log
Full tanks need comparable fill levels. Missing fill-ups, odometer rollover or inconsistent tank levels invalidate the model. Overall L/100 km uses total completed-interval litres divided by total completed distance, multiplied by 100. Download your data to keep it: this tool does not automatically persist records or store receipts.