Free IP and subnet calculators
Your network.
Made clear.
From a single address to a complete network plan. Calculate the values, check the result and understand how it works.
IPv4 or IPv6. Without a prefix, we use an example /24 or /64 — check it against your network settings.
Explore all tools192.168.1.10/24
- Network address
- 192.168.1.0
- Subnet mask
- 255.255.255.0
- Broadcast
- 192.168.1.255
- Usable hosts
- 254
✓A result explained, step by step
/24 → /26.0/2662 hosts.64/2662 hosts.128/2662 hosts.192/2662 hostsExample: splitting 192.168.1.0/24 into equal subnets.
Built for everyday work
Pick your tool.
Addressing, planning and verification.
Every calculation runs in your browser.
IPv4 subnet calculator
Calculate the network address, broadcast, host range and mask from IPv4/CIDR. Explore examples and /31 and /32 exceptions. No sign-up.
IPv6 calculator
Compress or expand IPv6 notation and calculate the network prefix and address range. Check the address type and learn from worked examples.
VLSM calculator
Enter an IPv4 network and the host count for each subnet. Get a VLSM plan with masks, address ranges and allocation explained.
FLSM calculator
Split an IPv4 network into equal-sized FLSM subnets. Check prefixes, network addresses, hosts and broadcasts, such as a /24 split into /26 blocks.
CIDR and mask converter
Convert a CIDR prefix to an IPv4 subnet mask or a mask back to a prefix. See the wildcard mask and the result in binary.
IPv4 converter: DEC, HEX, BIN
Convert IPv4 to decimal, hexadecimal or binary and back again. Understand how the same address is stored as an unsigned 32-bit number.
DHCP pool calculator
Plan an IPv4 DHCP pool with a proposed gateway, client range and exclusions. Work through an example without changing device settings.
Wildcard and ACL checker
Check whether an IPv4 address matches an ACL pattern and wildcard mask. Compare contiguous and non-contiguous masks with the bits explained.
Route aggregation calculator
Combine IPv4 subnets and address ranges into an exact set of CIDR blocks. Remove overlaps without adding addresses outside your input.
Download time calculator
Calculate download time, bandwidth or file size. Compare Mbps with MB/s, GB with GiB, and account for transfer efficiency.
Understand the why
More than numbers.
Knowledge that stays.
Subnets, prefixes and protocols explained through examples. Go from a calculator result to the principles behind it.
Explore the guides →IPv4 subnetting tutorial — masks, networks and hosts
IPv4 addresses, masks, CIDR prefixes, network and broadcast addresses, with /24, /26, /31 and /32 examples.
IPv6 tutorial — notation, prefixes and subnetting
IPv6 structure, RFC 5952 notation, prefixes, address types, SLAAC, DHCPv6, DNS, and URLs.
CIDR explained — prefixes, masks and route aggregation
Convert prefixes and masks, find block boundaries, split networks, and aggregate routes safely.
VLSM tutorial — a worked subnet planning example
Plan different-sized subnets, choose prefixes, align blocks, and work through a complete /24 example.
DHCP explained — DORA, leases and address pools
DHCPv4 messages, options, lease renewal, relay, pool planning, troubleshooting, and security.
CCNA foundations — study plan and your first network
A study map aligned with the current Cisco 200-301 CCNA v1.1 exam and the announced v2.0 transition.
Download time explained — Mbps, MB/s and MiB
Calculate transfer duration, distinguish bits from bytes and MB from MiB, and account for link efficiency with worked examples.