Feature Flag Blast Radius Calculator

10% sounds small until you see the real number.

Choosing a feature flag rollout percentage is often a gut-feel decision — 5%, 10%, 25% all sound appropriately cautious in the abstract. This calculator turns that gut feeling into real numbers: given your total user base, rollout percentage, expected bug error rate, and realistic detection-and-rollback time, it calculates exactly how many users are exposed, how many would be affected if the flag has a bug, how many additional sessions get exposed during the detection window before rollback, and the estimated dollar cost of that window — plus a full comparison table across common rollout percentages.

• →Calculates exact exposed-user counts at your chosen rollout percentage, not just a vague sense of scale
• →Factors in a realistic detection-and-rollback time window, not just a snapshot at the moment of full rollout
• →Produces a full comparison table across 1%, 5%, 10%, 25%, 50%, and 100% rollout percentages side by side
• →Estimates dollar cost of a bad rollout window using your own average session value
• →Watermarked by Cikal Studio Labs · Works on any device, no install required