How to Calculate Index Size

What is Index Size?

A database index size estimator calculates how much disk space database indexes will consume based on the number of rows, indexed column sizes, and index type. Indexes speed up queries but consume 20–100% of the table size in additional storage; over-indexing slows write performance.

Step-by-Step Guide

1Determine indexed columns
2Calculate bytes per index entry
3Project total index size

Worked Examples

Input

1M rows, 3 indices, 8 bytes each

Result

~24MB total

Plus B-tree overhead

Common Mistakes to Avoid

✕Wrong parameters
✕Missing adjustments

Frequently Asked Questions

What does this calculator do?

Set parameters

How do I use this calculator?

Run calculation

Ready to calculate? Try the free Index Size Calculator

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