Mid-RSVP, project the final count. The response rate is replies over invitations; apply the running acceptance rate to the outstanding invites to forecast the likely final headcount.
The example
140 replies of 200 invites.
| A | B | |
|---|---|---|
| 1 | Item | Value |
| 2 | Responses | 140 |
| 3 | Invitations | 200 → 70% |
The formula
The formula:
How it works
How it works:
- Response rate = responses ÷ invitations — how many have replied so far.
- Acceptance rate = Yeses ÷ responses — the share saying yes among repliers.
- Forecast final count:
current_yes + outstanding × acceptance_rate. - Chase the non-responders —
invitations - responses— before the caterer deadline.
Forecast, don’t guess. If 70% have replied and 80% of those said yes, the no-replies will likely accept at a similar (often lower) rate. Projecting current_yes + outstanding × acceptance_rate gives a defensible final number for the caterer weeks before the deadline — far better than waiting or over-ordering.
Try it: interactive demo
Invitations, responses, Yes so far.
Variations
Acceptance rate
Of those who replied:
Forecast final
Project no-replies:
Outstanding
Still to chase:
Pitfalls & errors
Two rates. Response rate (replied) ≠ acceptance rate (said yes) — use both.
No-shows happen. A few Yeses won’t attend — some planners shave 2–5%.
Mind the deadline. Caterers need the final count days ahead.
Practice workbook
Frequently asked questions
How do I calculate RSVP response rate in Excel?
How do I forecast the final headcount?
What's the difference between response and acceptance rate?
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