MotorMath
Cost of Ownership

Mileage Impact on Car Value

Calculate how extra miles reduce a vehicle's resale value using a per-mile depreciation rate.

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What this tool does

This calculator estimates the adjusted value of a vehicle at a target mileage by subtracting a linear depreciation adjustment from its current value. It multiplies the difference between target and current mileage by a user-supplied value-per-mile figure, then subtracts that total from the current value. The method assumes a constant per-mile depreciation rate across the mileage range; real-world depreciation curves are rarely linear and vary by make, model, age, and condition.

Inputs
(£)
(mi)
(mi)
(£)
Result
Result

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Formula
Car value at target mileage
Current car value in pounds
Target mileage in miles
Current mileage in miles
Depreciation per mile in pounds

How Mileage Impact on Car Value works

The calculator takes a vehicle's current value and current odometer reading, then projects its value at a higher (or lower) target mileage. The user supplies a per-mile depreciation figure—typically derived from market data or online valuation tools—and the engine multiplies the extra miles travelled by that rate. The product is subtracted from the current value to yield an adjusted estimate.

The formula

Adjusted value = Current value − (Target mileage − Current mileage) × Value per mile.

Each variable is user-defined: Current value in pounds, both mileage figures in miles, and the per-mile rate in pounds. If target mileage is lower than current mileage, the adjustment becomes positive, adding value back—a scenario more common when estimating past worth or correcting odometer discrepancies.

Where this method is most accurate

Linear per-mile depreciation works best over short mileage intervals on mid-life vehicles where age and wear accumulate predictably. The model breaks down for very low or very high mileage, where depreciation accelerates (early steep drop) or flattens (older cars losing little incremental value). It also assumes the per-mile rate remains constant; in reality, luxury and sports cars often lose more value per mile than economy models, and the first 10,000 miles typically cost more than miles 60,000–70,000.

What this tool does not do

It does not account for age-based depreciation, service history, accident records, cosmetic condition, market demand shifts, or regional pricing variations. The per-mile rate is an input, not a prediction; users must source it from valuation guides or comparable sales. The calculator performs no appraisal, provides no guarantee of resale price, and does not adjust for optional equipment, trim level, or seasonal demand.

Disclaimer

This tool is provided for educational and informational purposes only. It does not constitute financial, vehicle-appraisal, or purchasing advice. Actual resale values depend on numerous factors beyond mileage. Always consult independent valuation services and inspect vehicles in person before making buying or selling decisions.

Questions

Why does my result show a negative value?
If the mileage increase multiplied by the per-mile rate exceeds the current value, the adjusted figure will fall below zero. This indicates the depreciation assumption is too aggressive for the vehicle's starting value or mileage range.
Can I use this for electric vehicles?
Yes—the maths are identical. However, battery degradation can introduce additional depreciation not captured by odometer miles alone, so per-mile rates for EVs may differ from petrol equivalents.
Where do I find a realistic per-mile depreciation rate?
Online valuation tools (AutoTrader, Parkers, Glass's) often display value ranges at different mileage points for the same age and model. Divide the difference in value by the difference in miles to estimate a rate.
Does the calculator account for service history or condition?
No. It applies a flat per-mile rate to the current value. Vehicles with full service history, new tyres, or accident damage will depreciate at different real-world rates; adjust the per-mile input accordingly.
What if my target mileage is lower than current mileage?
The calculator subtracts a negative adjustment, effectively adding value back. This scenario is uncommon but can model retrospective valuation or odometer correction exercises.

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Sources & Methodology

The calculator computes (Target mileage − Current mileage) × Value per mile, then subtracts the product from Current value. This linear-depreciation model treats each additional mile as costing the same fixed amount. The per-mile rate is user-supplied; no embedded market data or age-adjustment curve is applied. Source: standard automotive depreciation accounting practice.

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