Database Backup Size Calculator
Size a backup set across full and incremental backups with retention.
About Database Backup Size Calculator
Retained full backups dominate backup storage, while incrementals are cheap because only changed data is captured. Compression typically removes two-thirds of the volume. Backup storage commonly exceeds the database several times over, which is a cost that surprises teams when retention policies are set without arithmetic.
Formula
Database Backup Size
Backup storage = full backups × compressed size + incrementals × daily change size
- incremental backup
- Captures only blocks changed since the previous backup
Worked example
With the default values below, Database Backup Size Calculator returns Total Backup Storage of 588.000. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Database sizeminimum 0 GB
- 400 GB
- Backup compression savingaccepts 0–100 %
- 70 %
- Daily change rateaccepts 0–100 %
- 3 %
- Full backups retainedminimum 0
- 4
- Incremental backups retainedminimum 0 days
- 30 days
Results
- Total Backup Storage
- 588.000 GB
- Size of One Full Backup
- 120.000 GB
- Size of One Incremental Backup
- 3.6000 GB
- Storage for Full Backups
- 480.000 GB
- Backup Storage as a Multiple of the Database
- 1.470 x
Step by step
- 1Values used
- 2Database Backup Size
- 3Total Backup Storage= 588.000 GB
- 4Size of One Full Backup= 120.000 GB
- 5Size of One Incremental Backup= 3.6000 GB
- 6Storage for Full Backups= 480.000 GB
- 7Backup Storage as a Multiple of the Database= 1.470 x
Assumptions and limits
- The result is derived only from the 5 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 4 decimal places, 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
How is Database Backup Size calculated?
Backup storage = full backups × compressed size + incrementals × daily change size Retained full backups dominate backup storage, while incrementals are cheap because only changed data is captured. Compression typically removes two-thirds of the volume.
Why does Database Backup Size matter?
Backup storage commonly exceeds the database several times over, which is a cost that surprises teams when retention policies are set without arithmetic.
What values do I need to enter?
This calculator takes 5 inputs: Database size, Backup compression saving, Daily change rate, Full backups retained, Incremental backups retained. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.