Database Indexing & Redis RAM Calculator
Size your database disk storage and Redis cache RAM for optimal performance.
e.g. 10,000,000 = 10 million rows
Typical: 0.5–5 KB for most OLTP tables
Typical: 20–40% for well-indexed tables
Storage & cache size appear here
Enter your DB details and click Calculate.
Database Storage Formulas
Total Data (GB) = Rows × Row Size (KB) × 1024 ÷ (1024³)
Index Size (GB) = Total Data × (Index Overhead %)
Redis RAM (GB) = (Hot Data + Hot Indexes) × 1.2
The 1.2x multiplier accounts for Redis overhead, key metadata, and memory fragmentation.
Frequently Asked Questions
What percentage of data is typically "hot"?
The 80/20 rule often applies: 20% of data receives 80% of reads. For most OLTP applications, caching 10–30% of the most-accessed data yields the biggest performance gains.
Why add 20% overhead to Redis sizing?
Redis stores data with metadata (key names, expiry, type headers) and has memory fragmentation. A 1.2× safety factor prevents OOM (out-of-memory) evictions in production.
When should I add more indexes?
Add indexes when query response time exceeds 50–100ms on frequently-run queries. Index trade-offs: reads get faster, writes get slower due to index maintenance. Avoid over-indexing write-heavy tables.
Last reviewed: October 2024
Sources:
PostgreSQL documentation· Redis memory model
Sizing estimates are approximations. Benchmark your specific workload for production capacity planning.