Premium Proration on Cancellation

Excel Formulas › Insurance

All versions

Cancel a policy mid-term and the unearned premium is refunded — pro-rata (full unused share) or short-rate (a penalty for early cancel). The refund depends on which method the policy uses.


Quick formula: pro-rata refund of unearned premium:
=annual_premium * days_remaining / 365
The unused days' share of the premium. Short-rate keeps a penalty, refunding slightly less.

The example

$1,200/yr, 120 days left.

AB
1ItemValue
21200 × 120/365—
3Pro-rata refund→ ~$394.52

The formula

The formula:

=annual_premium * days_remaining / 365 // unused days' share of premium

How it works

How it works:

  1. Earned premium = the days already covered; unearned = days remaining.
  2. Pro-rata refund = premium × days remaining ÷ 365 (insurer-initiated cancels).
  3. Short-rate keeps a penalty: refund × (1 − short_rate_penalty) — insured-initiated.
  4. The earned premium is the total minus the refund.

Illustrative math only — not insurance, financial, or legal advice. Policy language, state regulation, and carrier rules govern actual claims, premiums, and coverage. Always read the policy and consult a licensed professional.

Try it: interactive demo

Live demo

Annual premium, days remaining, short-rate penalty.

Pro-rata · Short-rate

Variations

Earned premium

Days used:

=annual_premium * days_elapsed / 365

Short-rate refund

With penalty:

=pro_rata_refund * (1 - short_rate_penalty)

Days remaining

From dates:

=expiration_date - cancel_date

Pitfalls & errors

Pro-rata vs short-rate. Who cancels usually decides the method.

Day count. Use actual days remaining ÷ 365 (or 366 in leap years).

Not advice. Refund method is set by policy and regulation.

Practice workbook

📊
Download the free Premium Proration on Cancellation practice workbook
A proration sheet with the earned-premium, short-rate, and days variants, plus 4 challenges with answers. No sign-up required.

Frequently asked questions

How do I calculate a premium refund in Excel?
Pro-rata: =annual_premium * days_remaining / 365. $1,200 with 120 days left refunds ~$394.52.
What's the difference between pro-rata and short-rate?
Pro-rata refunds the full unused share (usually insurer-initiated); short-rate keeps a penalty (usually insured-initiated).
How do I apply the short-rate penalty?
Multiply the pro-rata refund by (1 - penalty): =pro_rata_refund * (1 - short_rate_penalty).

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