Oil change interval calculator
Your manual prints two schedules, and almost nobody checks which one they're on. This works out which column applies to your driving, then tells you whether the distance or the months run out first.
Every number comes from your own manual and your own dashboard. We hold no intervals for any car. See below for why.
How to use it
Five minutes, and four of the five are spent finding one page in your glove box.
01Find the maintenance schedule in your manual
It's usually a fold-out table near the back, headed Scheduled Maintenance or Maintenance Log. If the car came without a manual, most manufacturers publish the same guide free on their owner site, searchable by VIN.
Glove box, or the maker's owner site02Read both columns, not the first one
The table gives two schedules. One is the everyday figure; the other is shorter and sits under a heading like special operating conditions. Type both distances and both month figures into the form. Four numbers in total.
Both are in the same table03Answer the driving question honestlyEasy to get wrong
The test is whether the majority of your driving fits, not whether it ever does. A single towing trip last summer doesn't put you on the short schedule; a daily two-mile commute in winter does.
This is the step people get wrong, and it's the reason the calculator exists.
Your own week, not your best week04Take two odometer readings and one date
The reading when the oil was last changed, the reading today, and the date of that change. The receipt or the sticker in the windshield usually has both. Never had it changed? Use the date the car was first registered.
Service receipt or windshield sticker05Read which limit arrives first
The answer gives you both: distance remaining and time remaining. Whichever runs out first is your real due point, and for a car that does few miles it is almost always the calendar.
If your car shows an oil life percentage, ignore all of this and follow the percentage. The first question on the form explains why.
Both numbers, not the bigger oneOil change facts
Your manual’s two columns are only the start. These are the other rules the same manuals and makers set around them, each with the document it comes from.
- A stopgap grade
Some manuals allow a second grade only when the right one isn’t available. Toyota says a 5W-20 used in place of 0W-20 must be replaced with 0W-20 at the next oil change; our guide to what to use instead of 0W-20 walks through it.
Source: Toyota Prius 2010 owner’s manual, p. 560; warranty and maintenance guide, p. 39 - The spec on the bottle
The grade tells you how the oil flows, and the spec tells you whether it meets your carmaker’s standard. GM warns that the wrong oil can cause engine damage the warranty won’t cover, and how to read an oil bottle shows where both are printed.
Source: Chevrolet Silverado 2014 owner’s manual, p. 10-12; API, Which Oil Is Right for You? - Cars built for synthetic
Some cars are certified for synthetic oil, and their schedule is written for it. The 2010 Prius maintenance guide says so on its cover, and synthetic versus conventional oil explains what the label really covers.
Source: Toyota Prius 2010 warranty and maintenance guide, cover and p. 38 - Turbo engines
The same model can need oil changes more often with the turbo engine. Hyundai’s 2016 Tucson manual sets 5,000 miles or 6 months for the 1.6 turbo after its first change, against 7,500 miles or 12 months for the 2.0.
Source: Hyundai Tucson 2016 owner’s manual, p. 7-9 - Diesel trucks
Ram’s 2018 diesel supplement says oil changes should never go past 10,000 miles or 12 months, whichever comes first. On biodiesel blends above 5 percent, known as B5, that cap drops to 8,000 miles or 6 months.
Source: 2018 Ram truck diesel supplement (3.0L diesel), p. 54 and 57 - Fuel in the oil
Honda told its dealers that CR-Vs driven on very short trips in some very cold states may get fuel in the engine oil. It answered with a software update and a longer warranty, the story told in the CR-V 1.5T oil dilution problem.
Source: Honda dealer messages MC-10147181 (October 2018) and MC-10158743 (April 2019) - A time limit, even when parked
Even if you hardly drive, GM, Honda and Ford want the oil changed at least once a year, and Nissan’s schedule says every 6 months. GM adds that its oil life system might not call for service for more than a year, and Ford says to change the oil before a car goes into storage.
Source: Chevrolet Silverado 2014 owner’s manual, p. 10-13; Honda CR-V 2018, p. 561; Ford F-150 2015, p. 502; Nissan 2013 maintenance guide, p. 10; Ford Edge 2011, p. 355 - Idle hours
Ford counts an hour of idling as about 33 miles of driving, and its 2010 guide caps the severe schedule at 5,000 miles, 6 months or 200 hours of engine running. Our guide to the oil change light covers how idle time shows up on the dashboard.
Source: Ford 2010 scheduled maintenance guide, p. 5, 42 and 43 - Some oil use is normal
Ford says a new engine’s oil use settles at its normal level after about 3,000 miles. Chrysler says hard, high-performance driving can use about a quart every 500 miles, which is why checking the level between changes matters.
Source: Ford Escape 2015 owner’s manual, p. 223; Chrysler 200 2015, p. 107
Four drivers in five are in the shorter column
shorter column
Technical Service Bulletin 94-1, Filter Manufacturers Council
That's not our estimate. Technical Service Bulletin 94-1, published by the Filter Manufacturers Council, reports that only about 20 percent of vehicles are regularly driven under “normal” conditions, which puts four out of five drivers in the other one.
The same bulletin makes a point about the vocabulary that is worth more than the statistic. It suggests the two columns would be better named ideal and average rather than normal and severe, because nobody thinks of their own commute as severe. The word does the damage: it sounds like it means rally driving, when it mostly means a short trip to work in the cold.
“Although the oil doesn’t wear out, the additives do.”Technical Service Bulletin 94-1
The mechanism isn't glamorous. On trips too short to bring the engine fully up to temperature, moisture and fuel condense into the oil and stay there. The bulletin is precise about what actually runs out: “Although the oil doesn't wear out, the additives do.” Detergents, dispersants, anti-oxidants and corrosion inhibitors are consumed, and once they're gone the oil is still oil but no longer doing the job.
Two sources, and they disagree
This is the part most pages skip, so here it is plainly.
TSB 94-1
2023 warranty and maintenance guide
TSB 94-1 says that any one of the severe conditions is enough: “any one of the above conditions can make it mandatory to change oil and filter” at the shorter interval.
Toyota’s own 2023 warranty and maintenance guide says the opposite about frequency. Its instruction is to perform the additional services “only if you drive primarily under the conditions indicated”, and its introduction is blunter still: “If you only occasionally drive under these circumstances, it's not necessary to perform the additional services.”
The lists differ too. TSB 94-1 names seven conditions. The Toyota guide we read names two: dusty or dirt roads, and towing or heavy loads. Short trips, idling, cold and mountains don't appear in it at all.
Notice who publishes each. The Filter Manufacturers Council is an association of companies that sell filters. Toyota builds the vehicle and pays the warranty claims. Both have an interest, and they point in opposite directions.
We have built this calculator on your own manual’s wording, because the whole position of this site is that the manual governs. That’s why the conditions step asks you to tick only the conditions your manual lists, and only when they describe the majority of your driving.
An oil life percentage isn't the same as a service light
These look alike on a dashboard and mean different things.
A percentage that counts down
A calculation · trust itA percentage that counts down is a calculation, and GM’s system is the best-known of them. It watches idle time, engine revolutions, oil temperature, coolant temperature, ambient temperature and oil pressure, and works out how much life the oil has left under the conditions your car has actually seen. Where a car has one, it supersedes the table.
A light or a message
Usually a counterA “Maintenance Required” light is usually just a counter. The Toyota guide we read says so in its own footnote: reset the reminder “after maintenance at every 5,000 miles”. It knows nothing about your oil. It knows about 5,000 miles.
So: if your car shows a percentage, trust it over anything on this page. If it shows a wrench or a message at a round number, that's a reminder, and the two columns in your manual still apply.
What this calculator doesn't do
- No vehicle data
It holds no intervals for any vehicle. There's no lookup by model, no database, and no default that pretends to know your car. The four figures come from your manual because that's the only place they're correct. Every calculator that ships its own numbers is telling somebody, somewhere, a wrong one.
- It can’t judge your oil
It also can't judge your oil. Interval arithmetic assumes the oil in the engine is the oil the manual was written around. Put conventional oil in an engine specified for full synthetic and the published interval no longer describes your situation. The calculator will say so, but it won't invent a replacement figure, because there isn’t an honest one to give.
- Viscosity: one rule only
The grade describes how the oil flows, not how long it lasts, and your carmaker sets the interval. But a grade your manual only allows as a stopgap can force an earlier change: Toyota says a 5W-20 used in place of 0W-20 must be replaced with 0W-20 at the next oil change.
- Nothing leaves your browser
Nothing you enter is sent anywhere. It runs in your browser, there's no server behind it, and there's nothing to sign up for.
Sources
The 20 percent figure, the “ideal and average” renaming, the additive-depletion explanation and the seven-condition list are from Technical Service Bulletin 94-1, Automotive Oil Change Intervals: Severe vs. Normal Driving, Filter Manufacturers Council, revised October 2013. Its own interval figures, 7,500 miles normal and 3,000 severe, are of their period and we haven't used them; modern schedules are considerably longer.
The “drive primarily” and “only occasionally” wording, the two-condition list and the 5,000-mile reminder-reset footnote are from the Toyota 2023 Warranty & Maintenance Guide for the Tundra, published by Toyota Motor North America.
The oil change facts and the stopgap-grade rule come from the owner’s manuals, maintenance guides and dealer messages named under each fact: Toyota, Chevrolet, Hyundai, Honda, Ford, Nissan and Chrysler, plus API’s consumer guide to motor oil. We read each document ourselves and quote only what it says.
What we didn't do: for the special-conditions wording we read one manufacturer guide, for one model and one year, and a second Toyota guide from the same year had no special-conditions section at all. So we can show that the definitions differ between sources. We can't tell you the industry has a single one, because on this evidence it doesn't. The oil life monitor description is the published behavior of GM’s system; we haven't tested any monitor, and we give no figure for how much life a given condition costs, because none of the sources quantifies it.