Service Interval Calculator
The next service odometer is simply the last-service reading plus the service interval.
Enter Values
How to use this calculator
- Enter your vehicle's service interval in km (from the handbook or service sticker), the odometer reading at the last service, and the current odometer reading.
- Optionally add your estimated yearly driving to convert the remaining distance into an approximate number of months.
- Read off the odometer figure the next service is due at and how far (or how long) remains — a negative remaining distance means it is already overdue.
How it works
The next service odometer is simply the last-service reading plus the service interval. Distance remaining is that due figure minus your current odometer: next = last + interval, and remaining = next − current. When the current reading is above the due figure the remaining distance is negative, which the tool reports as the amount overdue. Percent-of-interval-used is (current − last) ÷ interval × 100.
If you supply an estimated yearly driving distance, the tool converts the remaining kilometres into time. It works out a daily rate as annual ÷ 365, divides the remaining distance by that rate to get days, then divides by 365/12 to express the result in months. This is an estimate only — actual timing depends on how much you drive and whether the manufacturer also specifies a time-based limit (for example, whichever comes first of 15,000 km or 12 months).
Worked example
When is the next service due?. A car has a 15,000 km service interval, was last serviced at 42,000 km, and now reads 51,500 km. Next service is due at 42,000 + 15,000 = 57,000 km. The car has covered 9,500 km since the last service, so 5,500 km remain (63.3% of the interval used). Entering an estimated 20,000 km/year gives a daily rate of 54.8 km/day, so the next service is roughly 3.3 months away.
Common mistakes
- Confusing distance since the last service with the interval itself. Enter the odometer reading at the last service, not how far you have driven since — the tool works out the difference for you.
- Ignoring the time-based limit. Many manufacturers require a service at the interval distance OR a set number of months, whichever comes first. This tool schedules by distance; check your handbook for the time cap too.
- Mixing units. Keep every field in the same unit (all km, or all miles). If your interval is in miles, enter the odometer readings in miles as well so the arithmetic lines up.
Frequently asked questions
What does a negative or 'overdue' result mean?
It means your current odometer has already passed the point the next service was due. The tool shows how far past the due figure you are so you can book the service in promptly.
Does this account for time-based service limits?
Only if you enter an estimated yearly driving distance, and even then it just converts remaining kilometres to an approximate number of months. Manufacturers often state 'whichever comes first' between a distance and a time limit — always check your handbook for the time cap separately.
Can I use miles instead of kilometres?
Yes. The maths is unit-agnostic, so enter the interval and both odometer readings all in miles and the results will be in miles. Just don't mix miles and kilometres in the same calculation.
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Cite this tool
Zerdly. (2026). Service Interval Calculator. Retrieved from https://www.zerdly.com/tools/service-interval-calculator/
Tip: Enter any known values to calculate the remaining results.
Designed to run locally in your browser. Tool inputs are not intentionally stored by Zerdly unless stated otherwise.