# IPv4 Subnet Calculator – CIDR Tool

> Calculate network and broadcast addresses, first/last host, wildcard mask and usable hosts for any IPv4 subnet.

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# IPv4 Subnet Calculator

Network address, broadcast, host range, wildcard mask and binary breakdown for any IPv4 CIDR block.

## Results for 192.168.1.130/26

192.168.1.128/26 is the network in CIDR notation · Private (RFC 1918)

- **Network address:** 192.168.1.128
- **Broadcast address:** 192.168.1.191
- **Subnet mask:** 255.255.255.192
- **Wildcard mask:** 0.0.0.63
- **Total addresses:** 64
- **Usable hosts:** 62 (excludes network & broadcast)
- **First usable host:** 192.168.1.129
- **Last usable host:** 192.168.1.190
- **CIDR notation:** 192.168.1.128/26
- **IP type:** Private (RFC 1918)

### How the bits line up

|  | Octets (binary) |  |  |  |
| --- | --- |
| IP address | 11000000 | 10101000 | 00000001 | 10000010 |
| Subnet mask | 11111111 | 11111111 | 11111111 | 11000000 |
| Network | 11000000 | 10101000 | 00000001 | 10000000 |
| Broadcast | 11000000 | 10101000 | 00000001 | 10111111 |

The mask's 26 leading ones select the network portion; the remaining 6 bits are available for hosts.

## How to use the calculator

Type any block in CIDR notation — `10.0.0.0/22` — or supply an address with a dotted mask, e.g. `10.0.0.5 255.255.255.192`. The calculator accepts either form and derives the containing network from whichever host address you give it. Each field in the results panel means:

- **Network address** — the first address of the block, where the subnet begins.
- **Broadcast address** — the last address, delivered to every host on the segment.
- **First / last usable host** — the assignable range between those two endpoints.
- **Wildcard mask** — the inverted subnet mask used in Cisco ACLs and OSPF match statements.
- **Binary breakdown** — shows how the mask's leading ones divide network bits from host bits.

Worked example: enter `192.168.1.0/24`. With 24 network bits the mask is `255.255.255.0`, the network address is `192.168.1.0`, broadcast is `192.168.1.255`, and hosts may claim `192.168.1.1` through `192.168.1.254` — 254 usable addresses. The result link encodes your query in the URL, so sharing it reopens the identical calculation.

## Keep exploring

See every fact about the [/26 subnet mask](https://itinsighthub.com/subnet/26/), plan multiple subnets with the [VLSM calculator](https://itinsighthub.com/vlsm-calculator/), or convert ranges on the [range-to-CIDR tool](https://itinsighthub.com/ip-range-to-cidr/).

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