What it does
This calculator turns an F5 Distributed Cloud (XC) rate-limiter configuration into exactly what it will do. You enter the four fields F5's console asks for - Number, Per Period, Periods, and Burst Multiplier - plus the Mitigation Action (and a lockout if you choose Block), and it computes the effective rate, the per-second / minute / hour equivalents, the burst ceiling, and a plain description of the enforcement behavior. It runs entirely in your browser.
The rate math
XC expresses a rate as Number requests per (Periods x Per Period). That is why [1, Seconds, 60] and [1, Minutes, 1] are the same limit - one request per minute - which regularly surprises people. The calculator normalizes any configuration to a single window in seconds and shows the equivalent per-second, per-minute, and per-hour rates, so two configurations can be compared directly.
Burst and enforcement
The Burst Multiplier is the maximum burst of requests allowed, as a multiple of the rate (default 1); a 15 request/second limit with a 3x multiplier permits a 45-request burst. Enforcement is a leaky bucket: when the bucket overflows, the load balancer returns HTTP 429.
The mitigation gotcha
The single most misread setting is the Mitigation Action. Disabled does not bypass rate limiting - the leaky bucket still returns 429 on overflow; Disabled only means no extra lockout timer is applied. Block adds a lockout on top: once the bucket overflows, the user is blocked for the full lockout duration even if the bucket drains, and can send again only after the timer expires (maximum 48 hours). The calculator states which behavior your configuration produces.
Caveats it surfaces
Counting is distributed per Regional Edge and per proxy, so you may briefly see more requests than the limit before enforcement converges. And when you layer Server URL and API endpoint rules, they are evaluated first-match in the order you configure them.