Calculators › Policy Changes & Dates

Endorsement Premium Calculator

Calculate the pro-rata additional or return premium for a mid-term policy change (endorsement).

How the endorsement premium calculator works

When coverage changes mid-term, the carrier charges or refunds the annual premium difference only for the days left in the term. This calculator gives the AP or RP for any endorsement date.

Formula

AP / RP = (New annual premium − Current annual premium) × Days remaining ÷ Days in term.

How to use it

1. Enter the policy effective and expiration dates.
2. Enter the endorsement effective date.
3. Enter the annual premium before and after the change.

Worked example

A $12,000 policy increasing to $14,100 annual, endorsed five months in: the $2,100 annual change × 214/365 is about $1,231 additional premium.

Frequently asked questions

Why doesn’t the AP equal the annual difference?

Because the change only applies to the remaining part of the term.

Are small changes waived?

Many carriers waive additional or return premiums under a small threshold, often $5 to $25.

Related calculators

• Pro-Rata Cancellation Calculator — Calculate pro-rata return premium and earned premium when a policy cancels mid-term.
• Earned Premium Calculator — Calculate earned and unearned premium for any as-of date — for reserves, cancellations and reporting.
• Policy Effective Date Calculator — Calculate a policy’s expiration date, days in term, days remaining, renewal marketing date and non-renewal notice deadline.