Subscription Proration Calculator

Compute mid-cycle upgrade/downgrade proration charges.

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CurrencyOld plan price (per cycle) ($)New plan price (per cycle) ($)Billing cycle length (days)Days already used this cycle (days)

Mid-cycle upgrade proration: credit the unused portion of the old plan, then charge the new plan only for the remaining days.

$44

Charge due now (prorated)

Days remaining

$32

Unused credit (old plan)

$76

New-plan charge for remaining days

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Disclaimer: This tool is for general informational and estimation purposes only and is not professional financial, tax, accounting or legal advice. All figures are estimates — verify with a qualified professional before making decisions. Read the full disclaimer.

A customer wants to upgrade mid-cycle — what do you charge them today? Credit their unused days and bill the new plan only for the days remaining, in one quick calculation.

How to embed Subscription Proration Calculator on your website

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About Subscription Proration Calculator

When a customer upgrades mid-cycle, you credit the unused part of their old plan and charge the new plan only for the remaining days. This calculator works out the exact prorated amount due now.

How to use Subscription Proration Calculator

1Enter the old and new plan prices and cycle length.
2Enter how many days of the cycle are already used.
3Read the prorated charge due now and the unused credit.

Why use Subscription Proration Calculator?

✓Billing mid-cycle plan upgrades fairly.
✓Handling downgrades and plan switches.
✓Explaining a prorated invoice to a customer.

Frequently asked questions

How does subscription proration work?+

Proration credits the unused portion of the current plan and charges the new plan for the days remaining in the billing cycle. The amount due now is the new-plan remainder minus the old-plan credit.

How do I calculate a mid-cycle upgrade charge?+

Find the daily rate of each plan (price ÷ cycle days), multiply by the days remaining, then subtract the unused old-plan credit from the new-plan charge.