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Subnet Calculator

Enter an address and a prefix and get the network, broadcast, mask, wildcard, usable host range, and host count. Split a block into equal subnets, or check whether an address falls inside one. Includes a full CIDR reference table.

Accepts 10.0.0.0/24, 10.0.0.0 255.255.255.0, or a bare address (assumes /24).

Optional — test membership.

Try
192.168.1.0/24Network / prefix
254Usable hosts256 total addresses
255.255.255.0Subnet mask
0.0.0.255Wildcard mask
192.168.1.0Network address
192.168.1.255Broadcast
192.168.1.1First host
192.168.1.254Last host
PrivateAddress space
/24Prefix lengthPrivate (RFC 1918)
Mask in binary

11111111.11111111.11111111.00000000

4 subnets of 62 usable hosts each.

#NetworkFirst hostLast hostBroadcast
1192.168.1.0/26192.168.1.1192.168.1.62192.168.1.63
2192.168.1.64/26192.168.1.65192.168.1.126192.168.1.127
3192.168.1.128/26192.168.1.129192.168.1.190192.168.1.191
4192.168.1.192/26192.168.1.193192.168.1.254192.168.1.255
Method & assumptions
  • A /31 is treated as a point-to-point link under RFC 3021 — both addresses are usable.
  • A /32 is a single host: no network or broadcast address is reserved.
  • Host counts subtract the network and broadcast addresses for /30 and larger.
  • Everything runs in your browser. Nothing you type is sent anywhere.
ReferenceCIDR cheat sheet
IPv4 CIDR prefix, subnet mask, wildcard mask, and host counts
PrefixSubnet maskWildcardAddressesUsable hosts
/2192.0.0.063.255.255.2551,073,741,8241,073,741,822
/3224.0.0.031.255.255.255536,870,912536,870,910
/4240.0.0.015.255.255.255268,435,456268,435,454
/5248.0.0.07.255.255.255134,217,728134,217,726
/6252.0.0.03.255.255.25567,108,86467,108,862
/7254.0.0.01.255.255.25533,554,43233,554,430
/8255.0.0.00.255.255.25516,777,21616,777,214
/9255.128.0.00.127.255.2558,388,6088,388,606
/10255.192.0.00.63.255.2554,194,3044,194,302
/11255.224.0.00.31.255.2552,097,1522,097,150
/12255.240.0.00.15.255.2551,048,5761,048,574
/13255.248.0.00.7.255.255524,288524,286
/14255.252.0.00.3.255.255262,144262,142
/15255.254.0.00.1.255.255131,072131,070
/16255.255.0.00.0.255.25565,53665,534
/17255.255.128.00.0.127.25532,76832,766
/18255.255.192.00.0.63.25516,38416,382
/19255.255.224.00.0.31.2558,1928,190
/20255.255.240.00.0.15.2554,0964,094
/21255.255.248.00.0.7.2552,0482,046
/22255.255.252.00.0.3.2551,0241,022
/23255.255.254.00.0.1.255512510
/24255.255.255.00.0.0.255256254
/25255.255.255.1280.0.0.127128126
/26255.255.255.1920.0.0.636462
/27255.255.255.2240.0.0.313230
/28255.255.255.2400.0.0.151614
/29255.255.255.2480.0.0.786
/30255.255.255.2520.0.0.342
/31255.255.255.2540.0.0.122
/32255.255.255.2550.0.0.011

Click any row to load that prefix above.

The guide behind it

Subnetting, Explained

Want to know where these numbers come from rather than just having them? The guide walks the prefix bit by bit.

Read the guide

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