Backup Retention
Free Backup Retention calculator with clear step-by-step results.
About Backup Retention
A 3-2-1 style retention counts how many copies exist at each cadence.
Formula
Formula
Total = daily + weekly + monthly kept
Worked example
With the default values below, Backup Retention returns Total Backups of 23.00. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Daily backups keptminimum 0
- 7
- Weekly backups keptminimum 0
- 4
- Monthly backups keptminimum 0
- 12
Results
- Total Backups
- 23.00
- Coverage (weeks)
- 56.1
- Retention Rule
- Daily 7 · Weekly 4 · Monthly 12
Step by step
- 1Values used
- 2Formula
- 3Total Backups= 23
- 4Coverage (weeks)= 56.1
- 5Retention Rule= Daily 7 · Weekly 4 · Monthly 12
Assumptions and limits
- The result is derived only from the 3 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 1 decimal place, 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 does this calculator work?
A 3-2-1 style retention counts how many copies exist at each cadence.
Why does this matter?
Retention drives storage cost and recovery points.