Stripe proration calculator
When a subscription changes plans mid-cycle, what does the customer actually pay? Enter the old and new prices and where they are in the billing cycle to see the credit, prorated charge, and net due.
The change
Switching mid-cycle, Stripe credits the $13.33 of unused time on your current plan and charges $33.33 for the rest of the cycle on the new plan, a net $20.00 today.
Estimate only. Stripe prorates by the second using the real billing cycle length and proration settings, so exact amounts can differ by a few cents. Use Stripe's upcoming-invoice preview for the precise figure.
The method
How proration is calculated
Stripe splits a mid-cycle plan change into two prorated line items: a credit for the unused days on the current plan, and a chargefor the same remaining days on the new plan. The net is simply the charge minus the credit. On an upgrade that is a positive amount due now; on a downgrade it is usually a credit applied to the customer's balance.
Stripe prorates by the second against the real billing cycle, so this day-level estimate lands within a few cents. For the exact figure in code, preview the upcoming invoice before committing the change.
Common questions
Proration FAQ
How does Stripe proration work?
When a subscription changes plans mid-cycle, Stripe credits the unused portion of the current plan and charges for the remaining days on the new plan. By default it creates prorated line items that are billed on the next invoice; for upgrades you can charge immediately. The net amount is the new prorated charge minus the unused credit.
Does Stripe prorate by the day or by the second?
Stripe prorates by the second using the real billing cycle, so a change halfway through a 31-day month is calculated precisely. This calculator uses a day-level estimate (30 days for monthly, 365 for yearly), which lands within a few cents of Stripe's figure. For the exact amount, use Stripe's upcoming-invoice preview API.
What happens to the credit when a customer downgrades?
On a downgrade, the unused time on the more expensive plan is often worth more than the prorated charge for the cheaper plan. Stripe adds the difference to the customer's balance as credit, which is applied automatically against future invoices rather than refunded.
Can I turn proration off?
Yes. Stripe's proration_behavior parameter accepts create_prorations (the default), always_invoice (charge immediately), or none (no proration, the new price simply starts next cycle). Choose based on whether you want mid-cycle changes to be billed right away, deferred, or ignored.
Recover the payments that fail after a plan change
Upgrades and renewals are exactly where cards decline. SubRevival recovers those failed Stripe payments automatically with branded emails and a hosted card update page. $19/mo flat, 5-minute OAuth.