How much processing-fee you save by charging once a year instead of twelve times.
The saving is the 30¢ you skip eleven times, so it is largest on small monthly plans. Model the raw processing cost on the payment fee calculator and subscription add-ons on the Stripe billing fee calculator.
Free annual vs monthly fee calculator — seat price, seats and card fees to the processing-fee you save by billing annually.
The fixed per-transaction fee (about 30¢) is charged once a year instead of twelve times. On a small monthly amount that 30¢ is a big share of each charge, so avoiding it 11 times adds up. The percentage fee is the same either way.
On large charges. If the monthly amount is already big, the fixed 30¢ is a rounding error, so billing annually saves almost nothing on fees — a $300 annual plan versus twelve $25 charges saves only a few dollars. Annual billing still helps cash flow and churn, just not fees.