Pay-per-mile break-even calculator

What it tells you

Pay-per-mile insurance charges a monthly base rate plus a rate for each mile you drive, tracked by an app, a plug-in device or the car's connected services. It can save money for people who drive little — and cost more for people who drive a lot. The calculator finds the mileage where the two kinds of policy cost the same and charts both.

How to use it

1. Get a pay-per-mile quote and note the base rate (per month) and the per-mile rate (in cents).
2. If the program caps billable miles per day, enter the cap; a long road trip then costs less than the raw mileage suggests.
3. Get a traditional quote with the same coverage and deductibles and enter its monthly cost.
4. Enter the miles you drive in a typical month. Your car's service records or odometer photos a few months apart are the most reliable source.

The math

• Pay-per-mile monthly cost = base rate + per-mile rate × billable miles.
• Break-even = (traditional monthly cost − base rate) ÷ per-mile rate. Below that mileage, pay-per-mile is cheaper.

Before you switch

• Ask what the device or app records besides mileage, and whether driving behavior (speed, braking, phone use) affects the price. See what driving apps collect and how insurers use it.
• Check whether your mileage is seasonal. A summer of commuting can erase a winter of savings.
• A low-mileage discounts: how insurers reward driving less on a traditional policy may capture much of the saving without tracking.
• Make sure the coverage really matches; a cheaper policy with lower limits is not a like-for-like saving.

For the bigger picture, read usage-based car insurance explained and telematics programs from the major insurers compared.