A/B Testing Database Storage Per-User Calculator Examples
Worked examples showing how experiment volume, event rates, retention, and overhead change per-user storage estimates.
These examples use the same storage model with different experimentation patterns. They are planning illustrations, not measurements of a particular database system.
Lightweight experiment program
A product team assigns a user to 2 experiments, records one exposure per experiment per day, retains events for 30 days, and stores 250-byte events.
Input Summary
Active experiments
2
Exposure events per day
1
Conversion events per day
0.05
Retention
30 days
Assignment record size
150 bytes
Event record size
250 bytes
Overhead
25%
Calculation Breakdown
- 1Assignment storage2 * 150300 bytes
- 2Daily events2 * (1 + 0.05)2.1 events
- 3Raw event storage2.1 * 30 * 25015750 bytes
- 4Total storage(300 + 15750) * 1.2520062.5 bytes or 19.59 KB
Result Summary
Total storage
20062.5 bytes or 19.59 KB
A/B Testing Database Storage Per-User Calculator
Estimated storage is about 19.59 KB per user.
Standard 90-day experimentation setup
One user participates in 5 active experiments, with 1 exposure and 0.1 conversion events per experiment each day.
Input Summary
Active experiments
5
Exposure events per day
1
Conversion events per day
0.1
Retention
90 days
Assignment record size
150 bytes
Event record size
300 bytes
Overhead
30%
Calculation Breakdown
- 1Assignment storage5 * 150750 bytes
- 2Daily events5 * (1 + 0.1)5.5 events
- 3Raw event storage5.5 * 90 * 300148500 bytes
- 4Total storage(750 + 148500) * 1.30194025 bytes or 189.48 KB
Result Summary
Total storage
194025 bytes or 189.48 KB
A/B Testing Database Storage Per-User Calculator
Estimated storage is about 189.48 KB per user.
High-activity personalization testing
A user is in 12 experiments, each producing 3 exposures and 0.2 conversion events per day over 180 days.
Input Summary
Active experiments
12
Exposure events per day
3
Conversion events per day
0.2
Retention
180 days
Assignment record size
180 bytes
Event record size
450 bytes
Overhead
40%
Calculation Breakdown
- 1Assignment storage12 * 1802160 bytes
- 2Daily events12 * (3 + 0.2)38.4 events
- 3Raw event storage38.4 * 180 * 4503110400 bytes
- 4Total storage(2160 + 3110400) * 1.404357584 bytes or 4.16 MB
Result Summary
Total storage
4357584 bytes or 4.16 MB
A/B Testing Database Storage Per-User Calculator
Estimated storage is about 4.16 MB per user.
How to Read Your Results
The KB or MB result is an estimate for one user, not your full database.
Multiply the per-user value by a relevant retained-user count to estimate user-level data volume.
Compare scenarios by changing one driver at a time, such as retention days or daily exposure events.
Treat the overhead setting as a planning buffer rather than a measured database constant.
Add separate allowances for replicas, backups, shared configuration, and downstream copies.
Assumptions & Important Notes
- All users in each example have the same average experiment participation and event activity.
- Exposure and conversion records use the same average event record size.
- Events are retained for the entire period without sampling, compaction, or aggregation.
- Storage is expressed using 1024 bytes per KB and 1048576 bytes per MB.
Related Examples
Frequently Asked Questions
Can I multiply these examples by monthly active users?
Yes, if monthly active users are an appropriate proxy for the number of users whose records are retained. Define the user population consistently with your retention model.
Which input usually has the largest effect on storage?
Daily event volume, retention days, and event record size commonly have the largest effect because they are multiplied together.
Should exposure and conversion records have separate sizes?
This calculator uses one average event size. If their sizes differ materially, calculate them separately or use a weighted average.
Can I use zero conversion events?
Yes. The calculation still estimates assignment and exposure storage.
Ready to calculate your own result?
Use the live calculator with your own inputs, timing, and preferences.