Backup Strategy 3-2-1
Calculate Backup Strategy 3-2-1 instantly with the exact formula and a worked example.
Backup Strategy 3-2-1
Data sizeGB
Total copies, including the original
Different media types
Copies off-site
Annual failure probability of one copy%
Storage needed for all copies
1,500GB
Risk of losing all copies in a year
0.0125%
3-2-1 rule
Met
More about: Backup Strategy 3-2-1
What it calculates
The “Backup Strategy 3-2-1” calculator computes Storage needed for all copies in GB from 5 parameters: data size (GB), total copies, including the original, different media types, copies off-site, annual failure probability of one copy (%).
A handy everyday calculator for daily tasks.
Example calculation
With parameters Data size = 500 GB, Total copies, including the original = 3, Different media types = 2, Copies off-site = 1, Annual failure probability of one copy = 5 % the result is 1,500 GB (Risk assumes independent failures; a fire or ransomware can hit several copies at once).
How to use
- Enter data size, total copies, including the original, different media types, copies off-site and annual failure probability of one copy — each field above is adjustable with a slider.
- Storage needed for all copies (GB) is calculated automatically as you type.
- Check the worked example below to see the formula applied to real numbers.
- Copy the result or bookmark this calculator.
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FAQ
How is Backup Strategy 3-2-1 calculated?
The Backup Strategy 3-2-1 calculator computes Storage needed for all copies (in GB) from data size, total copies, including the original, different media types, copies off-site, annual failure probability of one copy. Enter your values above and the exact formula is applied instantly; a worked example with real numbers is shown below.
Is the Backup Strategy 3-2-1 calculator free?
Yes. It is completely free, needs no signup, runs entirely in your browser, and sends no data to any server.
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