IPv6 Subnet Count
Count equal-length IPv6 child prefixes using exact integers.
Your numbers
Child subnets
Planning estimate using your entered parameters. No external service, device, live tariff or network is contacted.
Scenario comparison
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Formula
Use S = 2^(c−p) and A = 2^(128−c). p is the parent prefix, c is the child prefix, S is the number of child subnets, and A is addresses per child subnet.
Count equal-length IPv6 child prefixes using exact integers.
Worked example
- Parent prefix length
- 48
- Child prefix length
- 64
- Child subnets
- 65536
- Addresses per child subnet
- 18446744073709551616
Scope and limitations
Planning estimate using your entered parameters. No external service, device, live tariff or network is contacted.
Inputs are checked for missing values and allowed ranges. A result outside the finite numeric range is not displayed. Rounding affects display, while the calculation uses the model’s numeric precision.
Check your units and assumptions before relying on a result. Changing a label does not convert a currency or physical unit.
Formula version: 74f46a066155 · Example checked: