IPv6 Subnet Calculator — Free Online Tool
Expand, prefix, range, type/scope, binary map and EUI-64 — for any IPv6 address.
Quick:
Network Details
Address Type & Properties
128-bit Binary Visualisation
■ network/prefix bits ■ interface bits
Subnet Splitter
IPv6 Special Address Ranges
| Range | Type | Description |
|---|---|---|
| ::1/128 | Loopback | Localhost (RFC 4291) |
| ::/128 | Unspecified | Unspecified address |
| fe80::/10 | Link-Local | Auto-configured, non-routable |
| fc00::/7 | ULA | Unique Local (RFC 4193) |
| ff00::/8 | Multicast | All multicast groups |
| 2000::/3 | Global Unicast | Public, globally routable |
| 2001:db8::/32 | Documentation | Docs / examples (RFC 3849) |
| ::ffff:0:0/96 | IPv4-mapped | IPv4-mapped IPv6 (RFC 4291) |
| 2002::/16 | 6to4 | 6to4 relay (RFC 3056) |
| 64:ff9b::/96 | NAT64 | IPv4/IPv6 translation (RFC 6052) |
About IPv6 Subnet Calculator
This complete IPv6 Subnet Calculator handles the full 128-bit address space in your browser. Paste a compressed or expanded IPv6 address with a prefix and instantly get the canonical compressed form, the fully expanded form, the network prefix, the first and last addresses in the range, the total address count, and hexadecimal representations.
It also detects the address type and scope (global, link-local, ULA, multicast, loopback and more), flags EUI-64 interface identifiers and IPv4-mapped addresses, draws a 128-bit binary map, and can split a prefix into equal subnets — everything locally and privately.
How to Use IPv6 Subnet Calculator
- Enter an IPv6 address (compressed or full) and a prefix length.
- Click Calculate.
- Review the expanded form, range, type/scope and binary map.
- Optionally split the prefix into equal subnets.
Key Features
Expand and compress IPv6 (RFC 5952)
Network prefix, first/last address and total count
Address type & scope detection with RFC
EUI-64 and IPv4-mapped detection
128-bit binary visualisation
Subnet splitter and special-range reference
100% client-side — nothing is uploaded
Frequently Asked Questions
What does this IPv6 calculator do?
Enter an IPv6 address and prefix length to get the compressed and fully expanded forms, network prefix, first and last addresses, total address count, hexadecimal forms, a 128-bit binary map, and the detected address type and scope.
How does IPv6 compression work?
Leading zeros in each 16-bit group are dropped and one run of all-zero groups is replaced with :: (only once). For example 2001:0db8:0000:0000:0000:0000:0000:0001 compresses to 2001:db8::1 (RFC 5952).
What is a /64 prefix?
A /64 uses the first 64 bits as the network and the last 64 as the interface identifier. /64 is the standard LAN segment size and is required for SLAAC auto-configuration.
What address types does it detect?
It identifies global unicast, link-local (fe80::/10), unique local / ULA (fc00::/7), multicast (ff00::/8), loopback (::1), unspecified (::), documentation (2001:db8::/32), IPv4-mapped, 6to4 and NAT64 ranges, with the matching RFC and scope.
Is anything uploaded?
No. All IPv6 math runs locally in your browser, so your input stays private.