Back-of-envelope calculations for system design interviews. Estimate QPS, storage, and bandwidth requirements.
Enter your system requirements
100.00 M users
Text ~1KB, Image ~500KB, Video ~50MB
Typical: 2-3x for normal apps, 10x for viral events
11.57 K
Average QPS
23.15 K
Peak QPS (2x)
1.00 B
Daily Requests
30.00 B
Monthly Requests
1.00 TB
Per Day
30.00 TB
Per Month
365.00 TB
Per Year
1.82 PB
5 Year Total
92.59 Mbps
Avg Bandwidth
185.19 Mbps
Peak Bandwidth
Memorize these for interviews
1 day
86,400 seconds
1 month
2.5M seconds
1 year
31.5M seconds
1 KB
1,000 bytes
1 MB
1,000 KB
1 GB
1,000 MB
1 TB
1,000 GB
1 PB
1,000 TB
Use our interactive System Design Canvas to build architectures with drag-and-drop components and get AI feedback on scalability, reliability, and performance.