SubNetCalc Homepage

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📰 Latest News
💡 What is SubNetCalc?
😀 Examples
📦 Binary Package Installation
💾 Build from Sources
🌏 Internationalisation
🔗 Useful Links

📰 Latest News

May 29, 2026
New release: subnetcalc-2.7.1. This version provides a build fix for FreeBSD with I18N-support turned off.
May 28, 2026
New release: subnetcalc-2.7.0. This release improves GeoIP support by replacing the deprecated libGeoIP by libMaxMindDB. This also results in GeoIP support available under FreeBSD again. Furthermore, IDN support has been added for FreeBSD.
News Archive
Go to the News Archive

💡 What is SubNetCalc?

SubNetCalc is an IPv4/IPv6 subnet address calculator. For given IPv4 or IPv6 address and netmask or prefix length, it calculates network address, broadcast address, maximum number of hosts and host address range. Also, it prints the addresses in binary format for better understandability. Furthermore, it prints useful information on specific address types (e.g. type, scope, interface ID, etc.).

😀 Examples

My host has IP 132.252.150.154 and netmask 255.255.255.240. What are the details of its network?

user@host:~$ subnetcalc 132.252.150.154 255.255.255.240
Address        = 132.252.150.154
                    10000100 . 11111100 . 10010110 . 10011010
Network        = 132.252.150.144 / 28
Netmask        = 255.255.255.240
Broadcast      = 132.252.150.159
Wildcard Mask  = 0.0.0.15
Hex. Address   = 84FC969A
Hosts Bits     = 4
Max. Hosts     = 14   (2^4 - 2)
Host Range     = { 132.252.150.145 - 132.252.150.158 }
Properties     =
   - 132.252.150.154 is a HOST address in 132.252.150.144/28
   - Class B
GeoIP Country  = Germany (DE)
DNS Hostname   = lupo.iem.uni-due.de

Consider host www.heise.de uses a 64-bit prefix length. What are the details of its network?

user@host:~$ subnetcalc www.heise.de 64
Address        = 2a02:2e0:3fe:1001:7777:772e:2:85
                    2a02 = 00101010 00000010
                    02e0 = 00000010 11100000
                    03fe = 00000011 11111110
                    1001 = 00010000 00000001
                    7777 = 01110111 01110111
                    772e = 01110111 00101110
                    0002 = 00000000 00000010
                    0085 = 00000000 10000101
Network        = 2a02:2e0:3fe:1001:: / 64
Netmask        = ffff:ffff:ffff:ffff::
Wildcard Mask  = ::ffff:ffff:ffff:ffff
Hosts Bits     = 64
Max. Hosts     = 18446744073709551615   (2^64 - 1)
Host Range     = { 2a02:2e0:3fe:1001::1 - 2a02:2e0:3fe:1001:ffff:ffff:ffff:ffff }
Properties     =
   - 2a02:2e0:3fe:1001:7777:772e:2:85 is a HOST address in 2a02:2e0:3fe:1001::/64
   - Global Unicast Properties:
      + Interface ID                     = 7777:772e:0002:0085
      + Solicited Node Multicast Address = ff02::1:ff02:0085
      + 6-to-4 Address                   = 2.224.3.254
GeoIP Country  = Germany (DE)
DNS Hostname   = www.heise.de

My new host should use Interface ID 0x100 and Subnet ID 0x1234. Generate a Unique Local IPv6 prefix (40-bit Global ID) for my intranet, according to RFC 4193, using high quality random numbers!

user@host:~$ subnetcalc 0:0:0:1234::100 64 -uniquelocalhq
Generating Unique Local IPv6 address (using /dev/random) ...
Address        = fd22:6892:1a2d:1234::100
                    fd22 = 11111101 00100010
                    6892 = 01101000 10010010
                    1a2d = 00011010 00101101
                    1234 = 00010010 00110100
                    0000 = 00000000 00000000
                    0000 = 00000000 00000000
                    0000 = 00000000 00000000
                    0100 = 00000001 00000000
Network        = fd22:6892:1a2d:1234:: / 64
Netmask        = ffff:ffff:ffff:ffff::
Wildcard Mask  = ::ffff:ffff:ffff:ffff
Hosts Bits     = 64
Max. Hosts     = 18446744073709551615   (2^64 - 1)
Host Range     = { fd22:6892:1a2d:1234::1 - fd22:6892:1a2d:1234:ffff:ffff:ffff:ffff }
Properties     =
   - fd22:6892:1a2d:1234::100 is a HOST address in fd22:6892:1a2d:1234::/64
   - Unique Local Unicast Properties:
      + Locally chosen
      + Global ID                        = 2268921a2d
      + Subnet ID                        = 1234
      + Interface ID                     = 0000:0000:0000:0100
      + Solicited Node Multicast Address = ff02::1:ff00:0100
GeoIP Country  = Unknown (??)
DNS Hostname   = (Name or service not known)

Which are DNS reverse lookup name and geo-location country of IP 2401:3800:c001::68?

user@host:~$ subnetcalc 2401:3800:c001::68
Address        = 2401:3800:c001::68
                    2401 = 00100100 00000001
                    3800 = 00111000 00000000
                    c001 = 11000000 00000001
                    0000 = 00000000 00000000
                    0000 = 00000000 00000000
                    0000 = 00000000 00000000
                    0000 = 00000000 00000000
                    0068 = 00000000 01101000
Network        = 2401:3800:c001::68 / 128
Netmask        = ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff
Wildcard Mask  = ::
Hosts Bits     = 0
Max. Hosts     = 0   (2^0 - 1)
Host Range     = { 2401:3800:c001::69 - 2401:3800:c001::68 }
Properties     =
   - 2401:3800:c001::68 is a NETWORK address
 - Global Unicast Properties:
    + Interface ID                     = 0000:0000:0000:0068
    + Solicited Node Multicast Address = ff02::1:ff00:0068
GeoIP Country = China (CN)
DNS Hostname  = bg-in-x68.1e100.net

Which are the MAC address and Solicited Node Multicast address of 2001:638:501:4ef8:223:aeff:fea4:8ca9/64?

user@host:~$ subnetcalc 2001:638:501:4ef8:223:aeff:fea4:8ca9/64
Address        = 2001:638:501:4ef8:223:aeff:fea4:8ca9
                   2001 = 00100000 00000001
                   0638 = 00000110 00111000
                   0501 = 00000101 00000001
                   4ef8 = 01001110 11111000
                   0223 = 00000010 00100011
                   aeff = 10101110 11111111
                   fea4 = 11111110 10100100
                   8ca9 = 10001100 10101001
Network        = 2001:638:501:4ef8:: / 64
Netmask        = ffff:ffff:ffff:ffff::
Wildcard Mask  = ::ffff:ffff:ffff:ffff
Hosts Bits     = 64
Max. Hosts     = 18446744073709551615   (2^64 - 1)
Host Range     = { 2001:638:501:4ef8::1 - 2001:638:501:4ef8:ffff:ffff:ffff:ffff }
Properties     =
   - 2001:638:501:4ef8:223:aeff:fea4:8ca9 is a HOST address in 2001:638:501:4ef8::/64
   - Global Unicast Properties:
      + Interface ID                     = 0223:aeff:fea4:8ca9
      + MAC Address                      = 00:23:ae:a4:8c:a9
      + Solicited Node Multicast Address = ff02::1:ffa4:8ca9
GeoIP Country  = Germany (DE)
DNS Hostname   = (Name or service not known)

Take a look into the manual page of SubNetCalc for further information and options:
```
man subnetcalc
```

📦 Binary Package Installation

Please use the issue tracker at https://github.com/dreibh/subnetcalc/issues to report bugs and issues!

Ubuntu Linux

For ready-to-install Ubuntu Linux packages of SubNetCalc, see Launchpad PPA for Thomas Dreibholz!

sudo apt-add-repository -sy ppa:dreibh/ppa
sudo apt-get update
sudo apt-get install subnetcalc

Fedora Linux

For ready-to-install Fedora Linux packages of SubNetCalc, see COPR PPA for Thomas Dreibholz!

sudo dnf copr enable -y dreibh/ppa
sudo dnf install subnetcalc

FreeBSD

For ready-to-install FreeBSD packages of SubNetCalc, it is included in the ports collection, see FreeBSD ports tree index of net/subnetcalc/!

sudo pkg install subnetcalc

Alternatively, to compile it from the ports sources:

cd /usr/ports/net/subnetcalc
make
sudo make install

💾 Build from Sources

SubNetCalc is released under the GNU General Public Licence (GPL).

Please use the issue tracker at https://github.com/dreibh/subnetcalc/issues to report bugs and issues!

Development Version

The Git repository of the SubNetCalc sources can be found at https://github.com/dreibh/subnetcalc:

git clone https://github.com/dreibh/subnetcalc
cd subnetcalc
sudo ci/get-dependencies --install
cmake .
make

Optionally, for installation to the standard paths (usually under /usr/local):

sudo make install

Note: The script ci/get-dependencies automatically installs the build dependencies under Debian/Ubuntu Linux, Fedora Linux, and FreeBSD. For manual handling of the build dependencies, see the packaging configuration in debian/control (Debian/Ubuntu Linux), subnetcalc.spec (Fedora Linux), and Makefile FreeBSD.

Contributions:

Issue tracker: https://github.com/dreibh/subnetcalc/issues. Please submit bug reports, issues, questions, etc. in the issue tracker!
Pull Requests for SubNetCalc: https://github.com/dreibh/subnetcalc/pulls. Your contributions to SubNetCalc are always welcome!
CI build tests of SubNetCalc: https://github.com/dreibh/subnetcalc/actions.
Coverity Scan analysis of SubNetCalc: https://scan.coverity.com/projects/dreibh-subnetcalc.

Current Stable Release

The tarball has been signed with my GnuPG key 21412672518D8B2D1862EFEF5CD5D12AA0877B49. Its authenticity and integrity can be verified by:

gpg --keyserver hkp://keyserver.ubuntu.com --recv-keys 21412672518D8B2D1862EFEF5CD5D12AA0877B49
gpg --verify subnetcalc-<VERSION>.tar.xz.asc subnetcalc-<VERSION>.tar.xz

Old Stable Releases

The tarballs have been signed with my GnuPG key 21412672518D8B2D1862EFEF5CD5D12AA0877B49. Its authenticity and integrity can be verified by:

gpg --keyserver hkp://keyserver.ubuntu.com --recv-keys 21412672518D8B2D1862EFEF5CD5D12AA0877B49
gpg --verify subnetcalc-<VERSION>.tar.xz.asc subnetcalc-<VERSION>.tar.xz

🌏 Internationalisation

To provide a translation of SubNetCalc into your language, apply the following steps:

Build SubNetCalc from the Git sources (see Development Version), i.e. use the “master” branch with the latest development version. The build will create a .pot (translation template) file under po.
Create a new Git branch for your translations, e.g. my_username/translations_language_XX (with XX the language code for your language, e.g. da for Danish):
```
git branch my_username/translations_language_XX
git checkout my_username/translations_language_XX
```
Take a look at the existing .po files (translations files) in po/de (German) and po/nb (Bokmål) as examples, e.g. po/de/subnetcalc.po or po/nb/subnetcalc.po. Then, prepare a translation for your language XX under po:
```
mkdir -p XX
msginit --input subnetcalc.pot \
        --locale XX.UTF-8 \
        --output-file XX/subnetcalc.po
git add XX/subnetcalc.po
```
Add your translations into XX/subnetcalc.po, with a text editor or PO file editor like Poedit.
Test, commit and push your changes.
Finally, make a pull request: https://github.com/dreibh/subnetcalc/pulls.

SubNetCalc An IPv4/IPv6 Subnet Calculator