Odometer Error Calculator
Estimate odometer error after a tire size change. See how many true miles or km pass per 1,000, 10,000 and 100,000 indicated.
Estimate distance recording differences.
Odometer Error Calculator: Tire Size Inputs
Compare two tire sizes here. Use the formulas and reference tables below for this tool's specific calculation.
How Odometer Error Calculator Works?
The Odometer Error Calculator works by multiplying indicated distance by the tire diameter ratio and reporting the unrecorded or over-recorded distance. The tool uses 3 steps.
Enter both sizes
Type the calibrated and fitted sizes.
Enter a distance
Type an indicated distance, for example a 12,000 mi (19,312 km) year.
Read the error
The calculator shows the true distance and the miles or kilometers the odometer missed or added.
Odometer Error Calculator Formula
The Odometer Error Calculator formula is Error = D_indicated × (CF − 1), where CF = OD_new ÷ OD_cal.
D_true = D_ind × CFE = D_ind × (CF − 1)E% = (CF − 1) × 100- D_ind
- Distance shown on the odometer
- D_true
- Distance actually traveled
- CF
- Correction factor
Worked example
A truck with a +3.49% tire upsize logs 12,000 indicated miles in a year. The truck travels 12,419 true miles (19,986 km), so the odometer misses 419 miles (674 km) per year.
Odometer Error Calculator Conversion Table
The Odometer Error Calculator conversion table shows the unrecorded or over-recorded distance for 7 size changes at 4 distance intervals.
| Size change | True distance per 1,000 indicated mi | Error per 10,000 mi | Error per 12,000-mile year | Error per 100,000 mi |
|---|---|---|---|---|
| +1.0% | 1,010 mi (1,625 km) | +100 mi | +120 mi | +1,000 mi |
| +2.0% | 1,020 mi (1,642 km) | +200 mi | +240 mi | +2,000 mi |
| +3.0% | 1,030 mi (1,658 km) | +300 mi | +360 mi | +3,000 mi |
| +3.5% | 1,035 mi (1,666 km) | +349 mi | +419 mi | +3,490 mi |
| +5.0% | 1,050 mi (1,690 km) | +500 mi | +600 mi | +5,000 mi |
| −2.0% | 980 mi (1,577 km) | -200 mi | -240 mi | -2,000 mi |
| −4.3% | 957 mi (1,540 km) | -430 mi | -516 mi | -4,300 mi |
What is Odometer Error Calculator?
An Odometer Error Calculator is a tool that estimates how far the odometer drifts from true distance after a tire size change. The odometer uses the same rotation count as the speedometer, so both carry the same percent error.
Speed error disappears when the driver lifts off. Odometer error accumulates every mile. A 4% upsize adds up to 4,000 unrecorded miles (6,437 km) over 100,000 indicated miles.
Warranty claims, lease returns and resale values all depend on recorded mileage.
What are the uses of Odometer Error Calculator?
There are 4 main uses of the Odometer Error Calculator, including warranty planning and lease mileage checks.
Warranty planning
Estimate true mileage at the end of a powertrain warranty.
Lease mileage checks
Know the true distance on a leased vehicle with non-stock tires.
Service intervals
Shorten oil-change intervals to match true distance.
Resale disclosure
Explain mileage differences to a buyer.
Related Speedometer & Distance Tools
View All 134 Subtools →Estimate speed changes after tire resizing.
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Calculate a tire-size correction multiplier.
Tabulate indicated and estimated actual speeds.
Adjust indicated distance for tire changes.