IPv6 Prefix Range and Address Calculator
Expand and normalize a hexadecimal IPv6 address and calculate exact numerical prefix boundaries and child-prefix counts.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Expand one optional :: sequence to eight 16-bit groups. Use 128-bit integer shifts to compute prefix base, final numerical address and address count; compress output with longest-leftmost zero-run rules.
Prefix count=2^(128−prefix); child blocks=2^(child prefix−parent prefix)
Worked example
2001:db8:1234:5678::abcd with /48 has base 2001:db8:1234:: and last numerical address 2001:db8:1234:ffff:ffff:ffff:ffff:ffff. It contains 65536 child /64 blocks.
Assumptions and input details
Hexadecimal hextet input with optional :: only; embedded IPv4 tails, zones, brackets and slash suffixes are explicitly unsupported. Compression is lowercase with the longest run of two or more zeros and leftmost tie. Counts are mathematical address capacity, not assignable-host promises, routing validation or configuration. No IPv4 broadcast deduction is applied.
References: IETF RFC 5952: IPv6 text representation
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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