Consumption from a fill-up
The most accurate way is "full tank to full tank": fill up completely, reset the trip meter, and at the next full fill-up enter the mileage and the litres from the receipt.
Trip cost
Loading current fuel prices…
The AI-92, AI-95 and diesel prices are in Belarusian rubles (BYN): fuel prices in Belarus are the same at every chain, set by the Belneftekhim concern, which is where they are fetched from. The "custom price" option works with any currency - the result comes out in whatever currency you enter.
Formulas
Consumption is litres / km × 100; fuel for
a trip is km / 100 × consumption; cost is litres × price. The cost
per kilometre covers fuel only - no depreciation, tyres or maintenance.
What affects consumption
City versus highway usually adds 20-40% to the brochure figure; winter adds warm-ups and winter tyres, summer adds air conditioning. Low tyre pressure and a roof box also raise consumption noticeably, so the honest number is the one you measure yourself - with the first calculator on this page.