BYTETOOLS

Subnet Mask Converter

Convert between CIDR prefix, dotted subnet mask, wildcard mask, hex and binary — with a full /0–/32 reference table. Free and 100% in your browser.

Converted mask

CIDR prefix
/26
Subnet mask
255.255.255.192
Wildcard mask
0.0.0.63
Hex mask
0xFFFFFFC0
Binary mask
11111111.11111111.11111111.11000000
Total addresses
64
Usable hosts
62

CIDR reference table (/0 – /32)

PrefixSubnet maskWildcardAddressesUsable hosts
/00.0.0.0255.255.255.2554,294,967,2964,294,967,294
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,646
/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 (RFC 3021 point-to-point)
/32255.255.255.2550.0.0.011 (host route)

What is the Subnet Mask Converter?

This Subnet Mask Converter translates freely between every common mask notation: CIDR prefix (/26), dotted-decimal mask (255.

  • Converts between prefix, dotted mask, wildcard, hex and binary
  • Complete /0–/32 table with addresses and usable host counts
  • Live highlight of your current prefix in the reference table
  • Rejects non-contiguous masks with a clear explanation
  • Copy button exports every representation at once
  • Fully client-side and works offline

How to use the Subnet Mask Converter

  1. 1

    Choose the format you are starting from: CIDR prefix, subnet mask, wildcard mask or hex.

  2. 2

    Type the value — for example /26, 255.255.255.192, 0.0.0.63 or FFFFFFC0.

  3. 3

    Read the equivalent value in every other notation from the results panel.

  4. 4

    Find your prefix highlighted in the full /0–/32 reference table below.

About the Subnet Mask Converter

This Subnet Mask Converter translates freely between every common mask notation: CIDR prefix (/26), dotted-decimal mask (255.255.255.192), Cisco wildcard mask (0.0.0.63), hex (0xFFFFFFC0) and raw binary. Pick the format you have, and read off all the others instantly.

It also renders the complete /0 to /32 reference table with each prefix's mask, wildcard, total addresses and usable hosts — the cheat sheet every network engineer keeps taped to a monitor, with your current value highlighted in place.

Input is validated properly: a dotted value whose binary 1-bits are not contiguous is rejected with an explanation rather than silently accepted. All conversion happens locally in your browser and nothing is sent anywhere.

Frequently asked questions

How do I convert a CIDR prefix to a subnet mask?

Write that many 1-bits from the left of 32 bits and fill the rest with 0s, then read each byte in decimal. /26 is twenty-six 1s: 11111111.11111111.11111111.11000000, which is 255.255.255.192. The converter does this instantly in both directions.

What is 255.255.255.192 in CIDR notation?

It is /26. The mask has 26 binary 1s, leaving 6 host bits, which gives 64 total addresses and 62 usable hosts per subnet.

Why is a mask like 255.255.192.255 invalid?

Subnet masks must have all their 1-bits contiguous from the left. 255.255.192.255 has 1s after a run of 0s, so no prefix length corresponds to it. This tool detects that and explains the problem instead of producing a wrong prefix.

What is the wildcard mask for a given subnet mask?

It is the bitwise inverse: flip every bit. The wildcard for 255.255.255.192 is 0.0.0.63. Cisco ACLs and OSPF network statements use wildcards, so the converter always shows both forms together.

How many usable hosts does each prefix length give?

Usable hosts are 2^(host bits) − 2, since the network and broadcast addresses are reserved — except /31 (2 usable on point-to-point links per RFC 3021) and /32 (a single host route). The reference table lists the exact figure for every prefix.

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