Tyre Life Calculator: Measuring Wear & Working Out the Cost

Tyre Life Calculator comes down to one division: cost per mile = tyre price ÷ expected mileage. A tyre that costs £130 as an example and lasts 30,000 miles costs 0.43 p per mile, and a set of four costs 1.73 p per mile. This page works the calculation out in full, shows the cost per mile for three example prices against three example mileages, and explains what moves the mileage — driving, alignment, pressure and load — and how to measure your own wear rate so the formula uses a real figure. Every price and mileage here is an example used to show the working; no tyre's real-world mileage is stated as fact.

On this page, tyre life calculator is the case in point: The reason cost per mile matters is that the price on the shelf is not the price of using the tyre: a dearer tyre that lasts longer can cost less per mile than a cheap tyre that wears out quickly, and the only way to know is to divide the price by the mileage. The table below makes the pattern visible — the cost per mile falls as the mileage rises and rises as the price rises — and the sections after it cover the factors that decide the mileage, the method for measuring it, the common mistakes, and the other costs that make up the full cost of driving. All figures are examples with the assumptions stated next to them.

tyre life calculator: The cost-per-mile formula

On this page, tyre life calculator is the case in point: Cost per mile = tyre price ÷ expected mileage. For a single tyre, divide the price of one tyre by the miles it is expected to cover. For a set of four, the cost per mile is (4 × tyre price) ÷ expected mileage, which is four times the single-tyre figure. The result is usually expressed in pence or cents per mile: a tyre costing £130 over an assumed 30,000 miles gives £130 ÷ 30,000 = £0.0043, or 0.43 p per mile. The mileage in the formula is the uncertain half — it is an assumption or a measurement, never a guaranteed property of the tyre — so the worked example below states its assumptions plainly, and the section on measuring wear shows how to replace the assumption with a figure measured on the actual car.

What cost per mile means for tyre life calculator

Cost per mile is the simplest way to compare tyres on value rather than on price: it divides what the tyre costs by how far it goes, so a dearer tyre that lasts longer can work out cheaper than a cheap tyre that wears out quickly. The formula is cost per mile = tyre price ÷ expected mileage, and for a set of four it is (4 × tyre price) ÷ expected mileage, which is four times the single-tyre figure. The result is usually a few pence or cents per mile, and the table in this article shows it for three example prices against three example mileages so the pattern is visible. Every price and mileage here is an example used to show the working, labelled as such — no tyre's real-world mileage is stated as fact, because it depends on driving, alignment, pressure and load. That is the point this page works through for tyre life calculator.

Worked example: £130 over 30,000 miles for tyre life calculator

Taking tyre life calculator as the case in point: Take a tyre priced at £130 as an example, with an assumed life of 30,000 miles. The cost per mile for one tyre is £130 ÷ 30,000 = £0.0043, which is 0.43 p per mile. A set of four costs £520 and lasts the same 30,000 miles, so the cost per mile for the set is £520 ÷ 30,000 = 1.73 p per mile. Over 10,000 miles of driving, the set costs 173.33 £ in tyre wear; over 12,000 miles a year it costs 208.00 £ a year. If the same tyre lasted 40,000 miles instead of 30,000, the cost per mile for the set would fall to 1.30 p; if it lasted only 20,000 miles, it would rise to 2.60 p. Both the price and the mileage are examples, labelled as such, and the mileage is the figure that matters most because it is the one that varies most between drivers.

Cost per mile table: three prices against three mileages for tyre life calculator

On this page, tyre life calculator is the case in point: All prices and mileages are examples used to show the working. Read across for the mileage and down for the price.

Tyre price (example) 20,000 miles 30,000 miles 40,000 miles
£90 0.45 p per mile 0.30 p per mile 0.22 p per mile
£130 0.65 p per mile 0.43 p per mile 0.33 p per mile
£180 0.90 p per mile 0.60 p per mile 0.45 p per mile

The table shows the two directions of the formula at once: moving right along a row, the cost per mile falls as the mileage rises, and moving down a column it rises as the price rises. A £90 tyre over 20,000 miles costs 0.45 p per mile, while the same tyre over 40,000 miles costs 0.22 p — the same tyre, the same price, and a very different cost per mile, decided entirely by how long it lasts. That is why the mileage deserves more attention than the price: it is the bigger lever, and it is the one the driver can influence by the way the car is driven and maintained. Compare tyres at the same assumed mileage so the comparison is like-for-like, and use a measured wear rate where one is available. That is the point this page works through for tyre life calculator.

tyre life calculator: What decides how long a tyre lasts

On this page, tyre life calculator is the case in point: The mileage in the formula is an estimate, and the factors behind it are worth listing because they decide whether the estimate is realistic. Aggressive driving wears tread faster than gentle driving, and the difference is large. Misalignment wears one edge of the tyre and can halve its life. Under-inflation wears the shoulders and builds heat; over-inflation wears the centre. Heavy loads, rough surfaces and hot weather all add wear, and a tyre that spends its life on motorways wears differently from one that spends it on town streets. The practical answer is to measure: note the tread depth when the tyres are fitted, measure it again after a known mileage, and the wear rate that comes out is the figure for that car and that driving — far more useful than any quoted number.

How to measure your own tyre mileage for tyre life calculator

Measuring your own tyre mileage is straightforward and makes the formula honest. Note the tread depth when the tyres are fitted — new tyres typically start around 8 mm in the UK — and the mileage on the odometer. After a known distance, measure the tread depth again with a gauge and note the mileage. The wear rate is (starting depth − current depth) ÷ miles driven, in millimetres per mile, and the remaining life is (current depth − legal minimum) ÷ wear rate. The legal minimum tread depth is 1.6 mm in the UK and 2/32 of an inch in the USA, and those limits are jurisdiction-specific and change, so check the current figure for the place the car is used. With the wear rate known, the cost-per-mile formula uses a mileage that belongs to the actual car rather than an assumption. That is the point this page works through for tyre life calculator.

tyre life calculator: Common mistakes with cost per mile

On this page, tyre life calculator is the case in point: A few errors spoil cost-per-mile comparisons. One is judging tyres by the price on the shelf instead of the price per mile — the dearer tyre that lasts longer is often the cheaper one to run. Another is taking a mileage figure from a brochure or a review and treating it as a fact about the tyre on your car, when mileage depends on driving, alignment, pressure, load and roads. A third is leaving fitting and balancing out of the price, which flatters the result. A fourth is comparing tyres at different assumed mileages, which makes the cheaper per mile figure an artefact of the assumption rather than the tyre. And the last is forgetting that the per-mile figure is for one tyre: multiply by four for the set, and remember that tyres are only one part of the cost of running a car.

tyre life calculator: Related pages

Frequently asked questions

How many miles do tyres last?

On this page, tyre life calculator is the case in point: There is no single figure that can be stated as a fact: it depends on the tyre, the car, the driving, the alignment, the pressures and the roads. The honest answer is to measure — note the tread depth when the tyres are fitted, measure it again after a known mileage, and the wear rate gives the remaining life. The section above explains the method step by step.

How do I measure tyre wear?

Taking tyre life calculator as the case in point: Use a tread-depth gauge: measure the depth when the tyres are fitted and again after a known mileage. The wear rate is the depth lost divided by the miles driven, and the remaining life is the depth left above the legal minimum — 1.6 mm in the UK, 2/32 inch in the USA — divided by that wear rate. Check the current legal limit for the jurisdiction.

What wears tyres out fastest?

Hard acceleration, heavy braking and fast cornering wear tread fastest, followed by misalignment, which scrubs one edge, and under-inflation, which wears the shoulders and builds heat. Smooth driving, correct pressures and correct alignment are the free ways to make tyres last longer, and each one shows up directly in the cost per mile. That is the point this page works through for tyre life calculator.

How can I make my tyres last longer?

For tyre life calculator, the point is this: Keep pressures at the placard figure, checked cold; have the alignment checked when the tyres show uneven wear; drive smoothly instead of accelerating hard and braking late; avoid overloading the car; and rotate the tyres if the manufacturer recommends it. Each of these extends the mileage in the formula, which cuts the cost per mile directly.

What is the legal minimum tread depth?

Taking tyre life calculator as the case in point: In the UK the legal minimum tread depth is 1.6 mm across the central three-quarters of the tread, and in the USA it is 2/32 inch. Both are jurisdiction-specific limits and they change, so check the current figure where the car is used. Most drivers replace tyres before the legal minimum, because wet grip falls off well before the tread is bare.