Cross-line tool
Pro-rata insurance calculator
Work out a pro-rata premium or refund from the daily rate and the days used.
Reviewed by Enu Zehra and Ms. Kakka, editors · Owner: Nadeem · hello@countrypilot.net (email only) · How we review
Educational estimates only. Calculated on your device. No account, no sign-up, no phone call.
Inputs
What this does not do: it does not quote, bind or compare insurer prices. It calculates straight pro-rata only — a share of the annual premium in proportion to the days. Some insurers cancel on a short-rate basis instead, which keeps back a penalty on top of the pro-rata share; if your insurer uses short-rate, the refund will be smaller than the figure here. Check your policy's cancellation wording before you rely on a refund figure.
About this tool
Published 2026-11-06.
What pro-rata means
Pro-rata is Latin for “in proportion”. A pro-rata premium is the annual premium divided by the days in the policy term, multiplied by the days of cover. A pro-rata refund is the annual premium minus the premium earned for the days already used. The same arithmetic answers five different searches — prorated calculator for insurance, pro rata insurance calculator, insurance pro rata calculator, pro rata calculator insurance, and the Excel-flavoured version — because they are all the same calculation: a daily rate times a number of days.
What you enter
Enter only your own figures. The annual premium from your policy documents, the policy term in days (usually 365), and the days used — or the days of cover you want. If your insurer charges a cancellation or admin fee, enter it; it is subtracted from the refund. The tool asks for no name, address, insurer or policy number, and it stores no insurer rate.
The method
Daily rate = annual premium / policy term in days. Earned premium = daily rate × days used. Refund = annual premium − earned premium − any fee. Premium for a short period = daily rate × days of cover wanted. The result is rounded to cents; the daily rate is shown to cents too, so a hand check of the arithmetic is straightforward.
Worked examples
Example 1 — refund. Annual premium $1,200, term 365 days, cancel after 90 days, no fee. Daily rate $1,200 / 365 = $3.29 a day. Earned premium 90 × $3.29 = $295.89. Refund $1,200 − $295.89 = $904.11.
Example 2 — short period. Annual premium $1,200, term 365 days, 30 days of cover wanted. Daily rate $3.29 a day. Premium for 30 days 30 × $3.29 = $98.63.
Example 3 — refund with a fee. Same figures as example 1, with a $50 cancellation fee. Refund $904.11 − $50 = $854.11. Enter the fee your own policy charges; the $50 here is illustrative only.
Pro-rata is not short-rate
Some insurers cancel on a short-rate basis, not pro-rata. A short-rate cancellation keeps back a penalty on top of the earned premium, so the refund is smaller than the pro-rata figure this tool gives. The difference is in the policy's cancellation wording — read it before you rely on a refund figure, and if the wording says “short-rate”, treat this tool's figure as the upper bound, not the refund.
What this calculator does not do
This tool does not quote, bind or compare insurer prices, and it does not know your insurer's cancellation table, minimum premium, or fee. It calculates straight pro-rata from the figures you enter. If your policy started mid-term, was endorsed mid-term, or was paid in instalments, the earned premium may be worked out differently by the insurer — the policy wording and the insurer's own calculation govern.
Related reading: the car claims guide on this site explains the cancellation and refund context for auto cover. For the general rule that a refund depends on the policy wording, see the exclusions and claims guides in the same line as your policy.
Questions about this tool
Is this result a quote from an insurer?
No. It is an educational estimate worked out from the numbers you entered, using the method below. No insurer rates are stored here and no carrier is compared.
Why does the result change when I change one input?
Because the calculation uses that input directly. Change one input at a time to see which one moves the result most — that is the quickest way to test a range.
What changes the result most?
Usually the biggest inputs you entered — the amount of cover, the deductible or limit, and any state or eligibility rule that applies. Change one input at a time to see which one moves the figure most.
Where do I check the rules behind this tool?
In the method section below and in the official source linked at the foot of the page. Rules and prices change, so the official source has the last word.
Reviewed by editors Enu Zehra and Ms. Kakka. Owner: Nadeem. Contact: hello@countrypilot.net (email only). General information only — not insurance, legal or financial advice.