Network, broadcast, host range, mask, and class from an IP + prefix.
Tip: use samples, upload, copy, download, and send-to actions inside the workspace where available.
IPv4 Subnet Calculator is a free, browser-based tool that helps you tidy up and standardize messy datasets. Network, broadcast, host range, mask, and class from an IP + prefix. It's built for speed and privacy: Everything runs locally in your browser — your data is never uploaded to a server. No sign-up, no installs, and no daily limits.
Clean obvious quality problems before analysis, imports, dashboards, or automation.
Review the preview, copy or download the result, and keep everything local in your browser.
Subnet Calculator: Plan subnets: network, usable range, broadcast, and mask.
Open toolCIDR Calculator: Turn a CIDR block into its address range, mask, and host count.
Open toolIPv6 Calculator: Expand, compress, and derive the reverse-DNS of any IPv6 address.
Open toolThe everyday form: four bytes, most significant first.
The address as one unsigned number — how routers and databases store it.
Two hex digits per octet; common in packet dumps and firmware.
Leading-zero octal. Historically accepted by inet_aton, a classic SSRF bypass.
The raw bit string used for masking.
Same bits grouped per octet — easiest way to see the mask boundary.
Per-octet hex, occasionally seen in vendor config files.
Every row is accepted as input too — paste the integer or hex form back into the field above and it converts the other way. The integer is computed as o1·2²⁴ + o2·2¹⁶ + o3·2⁸ + o4.
Default block for home routers. Matched against the IANA special-purpose registry; most specific prefix wins. Reference: RFC 1918.
Arithmetic happens on the 32-bit integer (3,232,235,786), then converts back to dotted form — which is why adding 256 moves the third octet by one and leaves the last octet untouched. Results outside 0 – 4,294,967,295 are rejected rather than silently wrapped.
| Dotted | Hex | Classification | ||||
|---|---|---|---|---|---|---|
| 0.0.0.0 | 0.0.0.0 | 0 | 0x00000000 | A | special | This host on this network (0.0.0.0/8) |
| 10.0.0.1 | 10.0.0.1 | 167,772,161 | 0x0A000001 | A | private | Private-Use (10.0.0.0/8) |
| 100.127.255.255 | 100.127.255.255 | 1,686,110,207 | 0x647FFFFF | A | special | Shared Address Space (CGNAT) (100.64.0.0/10) |
| 169.254.1.1 | 169.254.1.1 | 2,851,995,905 | 0xA9FE0101 | B | special | Link-Local (APIPA) (169.254.0.0/16) |
| 172.31.255.254 | 172.31.255.254 | 2,887,778,302 | 0xAC1FFFFE | B | private | Private-Use (172.16.0.0/12) |
| 192.168.100.200 | 192.168.100.200 | 3,232,261,320 | 0xC0A864C8 | C | private | Private-Use (192.168.0.0/16) |
| 203.0.113.9 | 203.0.113.9 | 3,405,803,785 | 0xCB007109 | C | special | Documentation (TEST-NET-3) (203.0.113.0/24) |
| 224.0.0.1 | 224.0.0.1 | 3,758,096,385 | 0xE0000001 | D (multicast) | special | Multicast (224.0.0.0/4) |
| 255.255.255.255 | 255.255.255.255 | 4,294,967,295 | 0xFFFFFFFF | E (reserved) | special | Limited Broadcast (255.255.255.255/32) |
| 8.8.4.4 | 8.8.4.4 | 134,743,044 | 0x08080404 | A | public | Globally routable unicast |
