Database Storage Sizing Calculator

Work out database storage sizing instantly with clear inputs, formula shown and shareable results.

About Database Storage Sizing Calculator

Database storage must cover the compounded data growth plus indexes, which commonly add 30 to 60 percent, plus free space for vacuum, rebuilds and temporary sort files. Compounding matters: 8 percent monthly growth over eighteen months is nearly a four-fold increase, so provisioning on today's size guarantees an emergency resize.

Formula

Storage projection

projected data = current x (1 + growth)^months; with overhead = projected x (1 + index share); provisioned = with overhead x 1.25

Worked example

With the default values below, Database Storage Sizing Calculator returns Storage to provision of 2,897. Change any input above and every figure here is recalculated in your browser.

Inputs used

Current data volumeminimum 0.001 GB: 400 GB
Monthly growthaccepts 0–100 %: 8 %
Planning horizonaccepts 1–120 months: 18 months
Index and overhead allowanceaccepts 0–300 %: 45 %

Results

Storage to provision: 2,897 GB
Projected data volume: 1,598 GB
Index and internal overhead: 719 GB
Free space reserve: 579 GB

Step by step

1Values used
2Storage projection
3Storage to provision= 2,897 GB
4Projected data volume= 1,598 GB
5Index and internal overhead= 719 GB
6Free space reserve= 579 GB

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to whole numbers, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Can cloud database storage be shrunk?

Generally no. Most managed services allow growth but not reduction, so over-provisioning is a permanent cost. Grow in steps rather than in one large jump.

Why reserve 25 percent free space?

Index rebuilds, vacuum operations and large sorts need working room. A database at 95 percent full cannot perform maintenance, which is how it becomes unrecoverable.