Guide Explains Back-of-the-Envelope Estimation for System Design

A DEV Community article explains how to produce rough traffic, storage, bandwidth, and capacity estimates from an ambiguous system design prompt. The approach is framed as a repeatable sequence: define the workload, compute average and peak requests per second, separate reads from writes, project data growth, and derive network throughput. The author stresses writing down assumptions such as user activity, payload sizes, retention periods, and traffic patterns before doing any arithmetic. The piece also offers quick conversion references, including seconds per day and per year, and notes the difference between decimal and binary data units. Its worked examples are presented as hypothetical inputs rather than benchmarks, and readers are advised to replace them with measured analytics and load-test data.