IPv4 Subnet Calculator (CIDR)
What are the network, broadcast, host range and mask for this CIDR block?
Spec sheet
ipv4_cidr · v1.0.0Bitwise IPv4 subnetting
- 01
mask = 2³² − 2^(32−prefix) - 02
network = ip AND mask; broadcast = network + 2^(32−prefix) − 1 - 03
usable hosts = 2^(32−prefix) − 2 (all addresses for /31 and /32)
- IPv4 only.
- RFC 4632 — Classless Inter-domain Routing (CIDR) ↗standard
- RFC 3021 — 31-bit prefixes on point-to-point linksstandard
Worked example
computed by the same formula192.168.1.10/24
- IPv4 address / prefix
- 192.168.1.10/24
- Network address
- 192.168.1.0
- Broadcast address
- 192.168.1.255
- First usable host
- 192.168.1.1
- Last usable host
- 192.168.1.254
- Usable hosts
- 254
- Subnet mask
- 255.255.255.0
- Wildcard mask
- 0.0.0.255
Questions
How is the ipv4 subnet calculator calculated?
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Bitwise IPv4 subnetting. mask = 2³² − 2^(32−prefix) · network = ip AND mask; broadcast = network + 2^(32−prefix) − 1 · usable hosts = 2^(32−prefix) − 2 (all addresses for /31 and /32)
Example: 192.168.1.10/24?
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Network address: 192.168.1.0; broadcast address: 192.168.1.255.
What does this calculator not cover?
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IPv4 only.
Where do the numbers come from?
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Sources: RFC 4632 — Classless Inter-domain Routing (CIDR); RFC 3021 — 31-bit prefixes on point-to-point links. The formula is versioned (ipv4_cidr v1.0.0) and covered by automated tests.
Is my data stored?
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No. The calculation runs in your browser and nothing is sent unless you choose to save a shareable link.
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