Proration calculator. With the working shown.
Type the old price, the new price and the day the plan changes. Read the credit, the charge, what is due today and the next invoice, with every step in plain numbers.
Prices are per period, before tax. Day 1 is the first day of the period. Quantity is for seats or units; leave it at 1 for a plan.
| Credit for unused time on the old plan | -$18.37 |
| Charge for the time left on the new plan | $62.70 |
| Net for the change | $44.33 |
The working
- The period has 30 days. The change lands on day 12, so 11 days used and 19 days left, the day of the change included.
- Credit for unused time on the old plan: $29.00 × 19 ÷ 30 = $18.37.
- Charge for the rest of the period on the new plan: $99.00 × 19 ÷ 30 = $62.70.
- Net for the change: $62.70 minus $18.37 = $44.33, due today.
- Next invoice: the new plan in full, $99.00 a month.
How proration works
When a subscription changes part way through a billing period, the customer should pay for exactly what they had: the old plan for the days before the change, the new plan for the rest. Proration is that split, written as two invoice lines.
Fraction = days left ÷ days in the period
Credit = old amount × fraction
Charge = new amount × fraction
Net = charge minus credit
An upgrade nets a charge; a downgrade nets a credit, which comes off the next invoice. The day of the change counts as a day on the new plan, and the credit and the charge each round to the cent on their own, so the invoice lines add up exactly as printed.
Proration in the glossary → Proration, explained with actual numbers →
yRecurring does this for you on every plan change, with the working on the invoice.
Upgrades, downgrades and seat changes are prorated to the day in your own timezone. Customers see a preview before they confirm, and every prorated line opens to the same steps you read above.
Questions about proration
What is proration?
When a subscription changes part way through a billing period, proration splits the period at the day of the change: the customer gets credit for the time they will not use on the old plan and pays for the time left on the new one. The two amounts together are what the change costs.
Does yRecurring prorate by the day or by the second?
By the calendar day, counted in your organisation's timezone. The day of the change counts as a day on the new plan, which is exactly what this calculator does, so its numbers match the invoice line to the cent.
Why is the net sometimes a cent away from the plain difference?
The credit and the charge are separate invoice lines, so each one rounds to the cent on its own, half up. The net is the difference of the two rounded lines, which can sit a cent away from working out the difference first and rounding once.
What happens on a downgrade?
The unused time on the dearer plan is worth more than the rest of the period on the cheaper one, so the customer is owed the difference. yRecurring keeps it as a credit on the next invoice instead of refunding it, and never raises a separate invoice for a credit.
Is the net charged straight away?
It is an organization setting you can override on a single change. The change can be invoiced the moment it happens, or the credit and charge can wait and land on the next regular invoice (the default), so the customer gets one invoice per period.