THE NUMBERS, EXPLAINED
How to use this calculator.
Returns aligned CIDR blocks exactly covering the inclusive IPv4 range.
Start with your inputs
Enter first ipv4 address, last ipv4 address. Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| First IPv4 address | 192.168.1.0 |
| Last IPv4 address | 192.168.1.255 |
A worked example
With the example inputs above, cidr blocks is 192.168.1.0/24. Change the inputs to explore your own scenario.
| Result | Example answer |
|---|---|
| CIDR blocks | 192.168.1.0/24 |
How this is calculated
CIDR blocks
coverIPv4range(a,b)
Symbols and units
- a
- First IPv4 address
- b
- Last IPv4 address
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Calculation steps and notation
Starting at the first address, choose the largest power-of-two block aligned to that address that fits inside the remaining inclusive range. Output its CIDR prefix, advance past it, and repeat until the final address is covered.
Assumptions and limits
Returns aligned CIDR blocks exactly covering the inclusive IPv4 range.
Calculations use the values you enter. Blank or invalid inputs show an error instead of silently substituting zero. Results are displayed to useful precision; calculations retain the underlying numeric precision.
Questions about this tool
What does the result tell me?
CIDR blocks. The result applies to the method and inputs described above. Check the units and assumptions before using it in a decision.
Why might another calculator differ?
Differences in units, rounding, timing or model definitions can produce different answers. Compare the input definitions and the method, rather than only the final number. For this tool: Returns aligned CIDR blocks exactly covering the inclusive IPv4 range.
Are my inputs stored or sent to AI?
Calculations on this page happen in your browser. The separate AI question finder sends its submitted conversation to OpenAI; these calculator fields are not sent. Favourites and recent tool names are stored locally. A shared link contains the inputs you choose to include.
Review status
Software example and browser checks are recorded in our quality report. No external expert review is claimed. Created with coding assistance; calculations run as ordinary browser code.
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