Twelve equivalent monthly periods
Current USD 1,000 and proposed USD 1,100 differ by USD 100 or 10%. Over twelve equivalent full periods, the comparison is USD 12,000 versus USD 13,200, with USD 1,200 difference. It is not promised cash.
Retainer billing
Free Recurring Fee Change Impact Calculator
Review a proposed recurring service-fee change on a consistent basis before seeking approval. Compare the same service and period length; the arithmetic does not change the agreement or predict cash collection.
What you can do here
Compare current and proposed fees for equivalent full periods, showing the signed change and totals over a chosen number of periods.
Built for real invoice workflows
Confirm the approved scope, fee and effective period before changing a future invoice draft or schedule.
Preparing your calculator with today’s date…
Calculation notes
How the result is calculated
Per-period difference = proposed − current. Percentage change = difference ÷ positive current fee × 100. Window totals = each fee × the entered whole-period count. The periods must be equivalent; twelve is not automatically an annual forecast. No partial-period proration, client approval, tax, service change, invoice schedule or collected revenue is inferred.
Formulas and examples reviewed October 2, 2026. Illustrative figures; no tax or contractual determination.
A lower fee over three periods
Current USD 1,000 and proposed USD 900 differ by USD −100 or −10%. Over three equivalent periods, the comparison decreases from USD 3,000 to USD 2,700. Any changed service scope needs its own review.
Questions about this calculation
Does this pick the right increase?
No. Enter the proposal you are reviewing. Costs, value, client negotiation and authority to change a price require separate decisions.
Can I apply the change halfway through a month?
Confirm effective dates and an approved partial-period method separately. This tool compares equivalent complete periods only.
How to use it
1
Enter a positive current fee and proposed fee for the same full-period basis.
2
Choose 1–24 equivalent periods for the comparison window.
3
Keep effective-date, scope, tax and partial-period decisions outside this comparison.
Why it helps
Show increases and decreases with their sign.
Translate a per-period change into an explicit comparison window.
Keep fee approval distinct from scheduled invoice changes.
Next step
From free tool to live invoice workflow.
Use the result when creating your invoice in InvoiceAgent. Planner setup links carry the settings they describe into a draft. Review your dates, amounts, PDF, and reminder settings before scheduling.
Related workflows
Move from the quick answer into the rest of the invoice system.
Draft the proposal clearly
Draft the proposal clearly
State scope, fee, effective period and requested decision.
Review approval and scheduling
Review approval and scheduling
Keep old and new service periods traceable.
Invoice templates
Invoice templates
Use the result inside invoice formats that are ready for clients and easier to automate.
Knowledge base
Knowledge base
Review the billing concepts behind the numbers before they go onto a live invoice.
Profession pages
Profession pages
See how freelancers, consultants, and agencies apply the same calculator output in different workflows.