Proration automation after an upgrade
To automate proration, configure your billing system to calculate time-weighted charges based on the difference between the old and new plan—triggered by the upgrade event timestamp. Most finance systems use one of two methods:
- Immediate proration: A one-time charge/credit issued the moment the upgrade occurs.
- Deferred proration: Proration calculated but applied at the next billing cycle, consolidating all charges.
Metric impact
ARR inflation risk if proration is missed or misapplied—especially if the upgrade bumps MRR by 15%+ but doesn’t show up until the next period.
Workflow trigger
Event: Customer clicks “Upgrade” → Billing logic: System compares old plan rate vs. new, calculates unused time value → System behavior: Prorated invoice generated or queued.
Key takeaway
Prorations are the most common failure point in recurring billing. Over-index on this area. Ensure mid-contract invoice adjustments are performed correctly to avoid customer experience issues.
Frequently Asked Questions
Should monthly proration calculations always use 30 days?
It depends on your billing policy. Some companies use 30 days for simplicity. Others use the actual number of calendar days in the billing cycle (28, 29, 30, 31).
Can I disable proration?
Most SaaS and subscription companies apply prorations when it results in additional revenue. For example, upgrades are typically prorated, but downgrades and cancellations are not.
Should proration create a new invoice?
Depends on your invoicing policies and the frequency of billing runs. Most opt to include prorated line item charges on a single bill to reduce customer confusion.
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