Developer tool
IP & Subnet Calculator
Calculate IPv4 and IPv6 network ranges and address counts.
IP & subnet calculatorCalculate network ranges and address counts from CIDR notation.
IPv4 · IPv6Without a prefix, IPv4 defaults to /32 and IPv6 to /128.
| Input address | 192.168.1.25 |
|---|---|
| Network CIDR | 192.168.1.0/24 |
| First address | 192.168.1.0 |
| Last address | 192.168.1.255 |
| Subnet mask | 255.255.255.0 |
| Wildcard mask | 0.0.0.255 |
| Broadcast | 192.168.1.255 |
| First host | 192.168.1.1 |
| Last host | 192.168.1.254 |
IPv4 /31 counts both point-to-point addresses; /32 is one address. IPv6 has no broadcast. Provider reservations and device allocation policies are not included.
Complete guide
How to use IP & Subnet Calculator
When to use it
Use an IP address and CIDR prefix to calculate network bounds, masks and exact address counts. Includes IPv4 host ranges, /31 and /32 handling, and IPv6 prefixes up to /128.
01
Three-step workflow
- 1
Enter an address and prefix such as 192.168.1.25/24.
- 2
Select Calculate or choose an IPv4/IPv6 example.
- 3
Review network bounds, masks and address counts, then copy the result.
02
What to enter and check
Enter an address and prefix such as 192.168.1.25/24.
Supports IPv4 /0–32 and IPv6 /0–128. Omitted prefixes default to /32 and /128 respectively. IPv4 requires four decimal octets rather than octal or abbreviated forms. Remove %zone identifiers from IPv6 inputs. An address with host bits is normalized to its network start in the result.
IPv4 /31 counts both addresses for a point-to-point link and /32 is a single address. IPv6 has no broadcast, so the last address is labeled separately. These are address-space calculations, not guaranteed device capacity. Provider reservations, gateway rules and device policies need separate verification. No network connection or port test is performed.
Practical example
192.168.1.25/24 spans 192.168.1.0 through 192.168.1.255: 256 total addresses and a conventional host range from .1 through .254. An IPv6 /64 has exactly 18,446,744,073,709,551,616 addresses, displayed without floating-point rounding.
How to read the result
IPv4 /31 counts both addresses for a point-to-point link and /32 is a single address. IPv6 has no broadcast, so the last address is labeled separately. These are address-space calculations, not guaranteed device capacity. Provider reservations, gateway rules and device policies need separate verification. No network connection or port test is performed.
05
Before you use the result
- IPv4 /31 counts both point-to-point addresses; /32 counts one address.
- Cloud provider reservations and actual device assignment policies require separate verification.
06
Frequently asked questions
How should I read the IP & Subnet Calculator result?+
IPv4 /31 counts both addresses for a point-to-point link and /32 is a single address. IPv6 has no broadcast, so the last address is labeled separately. These are address-space calculations, not guaranteed device capacity. Provider reservations, gateway rules and device policies need separate verification. No network connection or port test is performed.
What should I check for a more accurate IP & Subnet Calculator result?+
Supports IPv4 /0–32 and IPv6 /0–128. Omitted prefixes default to /32 and /128 respectively. IPv4 requires four decimal octets rather than octal or abbreviated forms. Remove %zone identifiers from IPv6 inputs. An address with host bits is normalized to its network start in the result. IPv4 /31 counts both point-to-point addresses; /32 counts one address.
Is my input uploaded or stored?+
No. This tool processes input in your current browser, and Baro Tool does not store the source content or result on its server.