Technology & Computing
Database B-Tree Index Fanout & Tree Depth Calculator
Estimate B-tree index fanout and tree depth from page size, key+pointer size and row count.
Your inputs
Change any value to update the result instantly.
Estimated tree depth
3 levels
Fanout (entries per page)
512
Leaf pages needed
1,95,313
Entry size
16 B
Total rows
10,00,00,000
Higher fanout (smaller keys, larger pages) reduces tree depth and disk I/O per lookup.
Formula and working
Fanout = page size ÷ (key size + pointer size); Depth = ceil(log_fanout(rows))
- 1
Collect the inputs
Page size (bytes) = 8,192 B; Key size (bytes) = 8 B; Pointer/row-ID size (bytes) = 8 B; Total rows in table = 100,000,000
- 2
Apply the formula
Fanout = page size ÷ (key size + pointer size); Depth = ceil(log_fanout(rows))
- 3
Result
Estimated tree depth = 3 levels
Frequently asked questions
Important limitation
This is an educational estimate based only on the values and formula shown. Verify current rates, rules, units, and professional standards before relying on the result. It is not personalized financial or investment advice.
Report a mistake or request an improvement
Tell us if a formula, unit, explanation, or result needs attention. Your message will include this calculator’s name and page.
Related calculators
Amdahl's Law Parallel Speedup Calculator
Calculate theoretical maximum speedup from parallelizing part of a workload across multiple processors, per Amdahl's Law.
CAN Bus Baud Rate & Bus Load Calculator
Calculate CAN bus load percentage from baud rate, average frame length and message frequency.
Consistent Hashing Ring Virtual Node Calculator
Estimate key distribution variance across shards on a consistent hashing ring based on virtual nodes per shard.
CPU Cache AMAT (Average Memory Access Time) Calculator
Calculate average memory access time from L1 hit time, miss rate and miss penalty, with an optional L2 level.
CPU MIPS from Clock Speed & IPC Calculator
Calculate CPU throughput in millions of instructions per second (MIPS) from clock speed and instructions per cycle.
GPU VRAM Requirement for LLM Inference Calculator
Estimate GPU VRAM needed to run an LLM at inference given parameter count, quantization bits, KV cache and overhead.