IPTools
Network calculators — choose your tool
Choose from 10 tools for IP addresses, subnet allocation, DHCP planning, route summarisation and transfer time.
Need the details of one address? Choose IPv4 or IPv6. Use FLSM for equal subnets or VLSM for different host requirements.
CIDR and the IP converter change notation; wildcard checks a match. Aggregation combines ranges, DHCP plans a pool, and the download calculator relates size, speed and time.
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.
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