Read the full display
Record the displayed mileage or kilometres consistently. If the dashboard shows tenths, keep them only if you plan to record them every time.
Free tool · Miles or kilometres
Odometer mileage calculator.
Enter your starting and ending odometer readings to calculate the distance driven. Add business distance if you also want a quick business-versus-personal split.
Distance driven—
Business distance—
Personal distance—
Business use—
This tool calculates distance from odometer readings. It does not decide whether a trip is deductible or reimbursable.
The calculation
How to calculate mileage from odometer readings.
Subtract the starting odometer reading from the ending reading. The result is the distance driven over that period.
Ending odometer12,725−Starting odometer12,450Distance driven275 miles
Odometer basics
What an odometer reading tells you.
An odometer shows the vehicle's cumulative distance travelled. A single reading is not a trip distance — the difference between two readings is what tells you how far the vehicle moved.
Use two readings
A start reading and an end reading create the distance for a trip, day, month or reporting period.
Keep business context
For work or tax records, distance alone is not the whole record. Keep the date, destination and business purpose that explain the drive.
Mileage records
Turn the number into a usable mileage record.
Odometer readings help establish distance, but business records are more useful when the trip details stay attached to that distance.
Starting odometerThe reading before the driving period.
Ending odometerThe reading after the driving period.
Date and destinationWhen the driving happened and where it went.
Business purposeWhy the driving was connected with work or business.
Quick answers
Odometer and mileage calculator questions.
How do I calculate mileage from an odometer?
Subtract the starting odometer reading from the ending reading. For example, 12,725 − 12,450 = 275 miles driven.
Can this calculator use kilometres?
Yes. Select kilometres before entering the readings. The calculator keeps the same unit throughout the result.
What if the ending odometer is lower than the starting reading?
The calculator will not produce a negative distance. Recheck the readings and make sure the start and end values came from the same vehicle and odometer unit.
Does an odometer reading prove business mileage?
It helps establish vehicle distance, but business mileage records normally need context such as the date, destination and business purpose. Keep those details with the distance record.
Is this the same as a mileage reimbursement calculator?
No. This tool calculates distance from odometer readings. A reimbursement calculator takes an already-known business distance and applies a mileage or kilometre rate.
Open the reimbursement calculatorHonestMile
Use the odometer when you need it. Track trips when you do not.
HonestMile keeps unlimited core trip recording free, so business and personal mileage can stay organized without rebuilding every drive from odometer readings later.