Back-of-the-envelope estimation.
also: back of the envelope estimation · back-of-envelope estimation · back-of-the-envelope · capacity estimationQuick, rounded arithmetic on traffic, storage, bandwidth and servers, so design decisions rest on numbers instead of guesses.
the two-minute refresher
- Four estimates: traffic (requests/s), storage, bandwidth and infrastructure (servers).
- Daily actions = DAU × actions per user; RPS ≈ daily actions ÷ 86,400 (about ÷ 100,000).
- Size for the peak, not the average, often 2-3× the average or more.
- Round aggressively and say your assumptions out loud: the reasoning matters more than the digits.