CalcaTools

Mileage Calculator | Track Fuel Economy, Cost Per Mile, and Trips

Calculate fuel economy in MPG and L/100km from miles driven and gallons used, and compute mileage reimbursement at any rate. Track your car's real efficiency and get your business-mileage payouts right.

Last updated: June 2026 · Free · No sign-up required

Results

Enter values above and click Calculate to see your result instantly.

Quick reference

Fuel cost per 100 miles (gas at $3.50/gal):

MPGGallons/100miCost/100mi
205.00$17.50
303.33$11.67
402.50$8.75
502.00$7.00

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Responsive design tested down to a 320px-wide phone screen. The input fields use native number/date keyboards on iOS and Android, the calculate button is thumb-sized, and the result still reads big and bold on the smallest screen. No app to download, ever.

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No newsletter pop-ups, no "create an account to see the answer", no fake countdown, no fake stock counter, no upsell. Two ad slots per page (clearly labelled as Advertisement) keep the site free — that's the whole business model.

Interpretation guide

Reading your numbers:

MetricWhat it means
MPGMiles driven per gallon — higher is better
L/100kmLiters per 100 km — lower is better
Cost per mileFuel spend divided by miles driven
ReimbursementBusiness miles x the IRS standard rate

lightbulb Worked example

Let's say you are using the Mileage Calculator. Tracks your vehicle's fuel economy and trip costs. Enter the odometer reading, or the miles driven and fuel used, and the tool calculates MPG, litres per 100 km, and the cost per mile or kilometre, Enter the values that match your situation into the input fields and press calculate — using realistic numbers makes the result directly useful for you.

Result: The calculator instantly applies the formula MPG = Miles / Gallons; L/100km = (Liters / km) x 100; Cost per mile = Fuel cost / Miles and returns the result with appropriate precision.

What this means: Read the result in the context of what you are measuring. The step-by-step breakdown lets you confirm the math and understand which input most affects the outcome.

Formula & methodology

Formula: MPG = Miles / Gallons; L/100km = (Liters / km) x 100; Cost per mile = Fuel cost / Miles

The Mileage Calculator is built on a well-established calculation method. It uses the formula MPG = Miles / Gallons; L/100km = (Liters / km) x 100; Cost per mile = Fuel cost / Miles to turn your inputs into a reliable result. Tracks your vehicle's fuel economy and trip costs. Enter the odometer reading, or the miles driven and fuel used, and the tool calculates MPG, litres per 100 km, and the cost per mile or kilometre, plus the estimated The steps are shown on the page so you can follow the reasoning from input to output.

Mileage is computed by dividing distance by fuel used (MPG) or fuel by distance (L/100km). The calculator also turns this into a trip fuel cost and a cost-per-mile figure when you add the fuel price. Track tank-to-tank MPG to spot maintenance issues, compare vehicles, or estimate the deductible cost of business driving.

Authoritative source: timeanddate.com

Frequently asked questions

How do I calculate my car's MPG?
Enter the required values into the input fields and press the calculate button. The tool applies the formula MPG = Miles / Gallons; L/100km = (Liters / km) x 100; Cost per mile = Fuel cost / Miles and returns the result with a short explanation of each step, so you can check the working yourself.
How do I convert MPG to L/100km?
Use the reciprocal conversion: L/100km = 235.215 ÷ MPG. A car getting 30 MPG uses about 7.84 L/100km, and 40 MPG is about 5.88 L/100km. The factor 235.215 comes from the units: 100 km ÷ (1.609 km/mile) ÷ (1 gallon ÷ 3.785 L) × 1 MPG. The calculator converts in both directions.
What is a good MPG?
The Mileage Calculator is free, private, and accurate: it runs entirely in your browser (no uploads, no accounts), applies the standard calculation, and explains each step so you can verify the result. Tracks your vehicle's fuel economy and trip costs. Enter the odometer reading, or the miles driven and fuel used, and the tool calculates MPG, litres per 100 km, and the cost per mile or kilometre, plus the estimated fuel cost of your regular trips. There is no limit on usage, and it works on any device.
How do I find cost per mile?
Yes — the Mileage Calculator. There is no sign-up, no paywall, no trial, and no limit on how many calculations you can run. CalcaTools covers its costs with non-intrusive display advertising, so the calculator itself never asks for payment or restricts any feature.
How do I calculate mileage reimbursement?
Multiply the business miles driven by the reimbursement rate: reimbursement = miles × rate per mile. The IRS standard rate (about 67¢ per mile in 2024, adjusted annually) covers fuel, maintenance, depreciation, and insurance. The calculator returns the reimbursement amount for any rate, so you can also compare the IRS rate with your employer's rate.
What does the Mileage Calculator do?
Tracks your vehicle's fuel economy and trip costs. Enter the odometer reading, or the miles driven and fuel used, and the tool calculates MPG, litres per 100 km, and the cost per mile or kilometre, plus the estimated fuel cost of your regular trips. The calculator takes your inputs, applies the standard calculation, and returns a clear result so you can make an informed decision without doing the math by hand.
What formula does the Mileage Calculator use?
The Mileage Calculator applies the standard formula: MPG = Miles / Gallons; L/100km = (Liters / km) x 100; Cost per mile = Fuel cost / Miles. The tool walks through each step of the calculation so you can verify the numbers yourself.
Is the Mileage Calculator free and private?
Yes — it is free with no sign-up or limits, and all calculations run in your browser so your trip data is never uploaded. CalcaTools funds itself with display ads. The tool converts between MPG and L/100km and computes mileage reimbursements at any rate.
How accurate is the Mileage Calculator?
The Mileage Calculator applies the standard formula: MPG = Miles / Gallons; L/100km = (Liters / km) x 100; Cost per mile = Fuel cost / Miles. It is tested against published worked examples before launch and uses native double-precision arithmetic, so results are accurate to typical precision for the values you enter — with no intermediate rounding that could distort the answer.

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