IP Subnet Calculator
Calculate IPv4 subnet details including network address, broadcast address, subnet mask, wildcard mask, CIDR prefix, usable host range and host capacity directly in your browser.
IPv4 Network
Enter an IPv4 address and CIDR prefix or subnet mask to calculate the complete subnet.
Example: 192.168.1.25
Choose a prefix from /0 through /32.
You can also enter a valid contiguous subnet mask directly. SwiftVecto will update the CIDR prefix automatically.
Subnet results will appear here
Enter an IPv4 address and prefix to calculate the network.
Network Summary
Main IPv4 subnet values.
Network
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Network Address
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Broadcast Address
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Subnet Mask
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Wildcard Mask
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Host Range
Address capacity and usable host information.
First Usable
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Last Usable
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Total Addresses
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Usable Hosts
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Network Bits
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Host Bits
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Address Classification
Informational classification of the entered IPv4 address.
Address Type
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Historical Class
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Classful addressing is historical; modern networks use CIDR.
Subnet Behaviour
How usable addresses are interpreted for this prefix.
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Quick Examples
Load a common subnet example and inspect the result instantly.
Binary View
Inspect the 32-bit values used in the subnet calculation.
IP Address
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Subnet Mask
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Wildcard Mask
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Network Address
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Broadcast Address
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Understanding CIDR
IPv4 addresses contain 32 bits. The CIDR prefix tells you how many of those bits identify the network.
For example, /24 means 24 network bits and 8 host bits, giving 256 total addresses.
A larger prefix creates a smaller subnet, while a smaller prefix creates a larger subnet.
Subnet Mask and Wildcard Mask
A subnet mask identifies which IPv4 bits belong to the network portion.
The wildcard mask is the inverse of the subnet mask and is commonly used in routing and access-control configurations.
/24 → 255.255.255.0 → 0.0.0.255
Special /31 and /32 Networks
/31
RFC 3021 allows both addresses in a /31 network to be used on point-to-point links, so SwiftVecto reports two usable addresses rather than applying the traditional network-and-broadcast subtraction.
/32
A /32 identifies one individual IPv4 address. It is commonly used for host routes, loopback addressing and precise routing entries.
Calculated in Your Browser
IPv4 subnet calculations run directly in your browser. No IP address or subnet configuration needs to be sent through SwiftVecto's processing queue.
Verify Production Changes
Always verify subnet calculations before changing production routers, firewalls, DHCP scopes, VPN configurations or access-control rules.
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How to Use the IP Subnet Calculator
Enter an IPv4 address and CIDR prefix or subnet mask to calculate the network address, broadcast address, usable host range, subnet mask, wildcard mask and other useful IPv4 subnet information instantly in your browser.
Overview
The SwiftVecto IP Subnet Calculator is designed for network administrators, developers, IT support teams, students and anyone working with IPv4 networks. It calculates the key properties of an IPv4 subnet from an IP address and CIDR prefix, including network and broadcast addresses, usable host range, total addresses, usable host count, subnet mask, wildcard mask, binary representations and address classification.
Benefits
How It Works
Enter a valid IPv4 address such as 192.168.1.25.
Enter or select a CIDR prefix such as /24.
SwiftVecto converts the IPv4 address and subnet mask into 32-bit binary values.
A bitwise AND operation determines the network address.
The inverse subnet mask is used to determine the wildcard mask.
Host bits are set to one to calculate the broadcast address.
The total address capacity is calculated from the number of host bits.
Where appropriate, the first and last usable host addresses are calculated.
The result is displayed immediately without uploading data to SwiftVecto.
How to Use This Tool
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1Enter an IPv4 address.
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2Choose or enter the CIDR prefix.
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3Review the calculated subnet mask.
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4Review the network and broadcast addresses.
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5Check the usable host range.
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6Review the total and usable address counts.
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7Inspect additional information such as wildcard mask, binary values and IP classification.
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8Change the address or prefix to calculate another subnet.
Helpful Tips
- A /24 network uses the subnet mask 255.255.255.0.
- A /16 network uses the subnet mask 255.255.0.0.
- A /8 network uses the subnet mask 255.0.0.0.
- A /30 subnet contains four addresses and is traditionally used for small point-to-point networks.
- A /32 identifies one individual IPv4 address rather than a conventional multi-host subnet.
- CIDR notation describes how many of the 32 IPv4 bits belong to the network portion.
- The wildcard mask is the inverse of the subnet mask.
- Always verify subnet calculations before changing production network configurations.
- Private IPv4 ranges are intended for internal networks and are not globally routable on the public internet.
- Modern networking primarily uses CIDR rather than the historical classful addressing system.
Common Uses
Calculate the subnet containing 192.168.1.25/24.
Find the network and broadcast addresses for 10.20.30.40/16.
Calculate the usable host range of 172.16.50.10/27.
Convert /26 into its equivalent subnet mask.
Find the wildcard mask for a /24 network.
Determine how many addresses are available in a /20 subnet.
Calculate a small /30 network for a point-to-point connection.
Inspect the binary representation of an IPv4 address and subnet mask.
Worked Examples
The following examples demonstrate how this tool can be used in realistic scenarios.
192.168.1.25/24
The network address is 192.168.1.0, the broadcast address is 192.168.1.255, the subnet mask is 255.255.255.0 and the traditional usable host range is 192.168.1.1 through 192.168.1.254.
10.0.0.10/8
The network address is 10.0.0.0, the broadcast address is 10.255.255.255 and the subnet mask is 255.0.0.0.
192.168.10.65/26
A /26 contains 64 addresses. The address 192.168.10.65 belongs to the 192.168.10.64 network with broadcast address 192.168.10.127.
192.168.1.4/30
A /30 network contains four addresses: one network address, two traditionally usable host addresses and one broadcast address.
Common Mistakes
Avoid these common mistakes to achieve the most accurate results.
- Entering an IPv6 address into an IPv4 calculator.
- Using an invalid octet greater than 255.
- Using a CIDR prefix below 0 or above 32.
- Confusing the network address with the first usable host address.
- Confusing the broadcast address with the last usable host address.
- Assuming every subnet follows the traditional network-plus-broadcast host calculation rules.
- Confusing subnet masks with wildcard masks.
- Treating historical IP classes as the primary method of modern subnet design.
- Making production routing or firewall changes without verifying the calculated network range.
Glossary
Definitions of the most important terms used by this tool.
IPv4 Address
A 32-bit Internet Protocol address normally displayed as four decimal octets, such as 192.168.1.25.
Subnet
A logical subdivision of an IP network defined by a network prefix.
CIDR
Classless Inter-Domain Routing notation expressing the network prefix length, such as /24.
Subnet Mask
A 32-bit mask identifying which parts of an IPv4 address represent the network and host portions.
Network Address
The first address in a conventional IPv4 subnet representing the subnet itself.
Broadcast Address
The final address in a conventional IPv4 subnet used for broadcast communication within that subnet.
Wildcard Mask
The bitwise inverse of a subnet mask, commonly used in access-control and routing configurations.
Host Bits
The IPv4 bits remaining after the network prefix and available to identify addresses within the subnet.
Usable Host Range
The range of addresses traditionally assignable to hosts after excluding the network and broadcast addresses where those concepts apply.
Private IPv4 Address
An address belonging to RFC 1918 private ranges used for internal networks.
Frequently Asked Questions
What is an IP subnet calculator?
An IP subnet calculator determines network information such as the network address, broadcast address, subnet mask, wildcard mask, host range and subnet size from an IPv4 address and network prefix.
What does /24 mean?
A /24 prefix means the first 24 bits of the IPv4 address identify the network. It corresponds to the subnet mask 255.255.255.0.
What does /16 mean?
A /16 prefix uses 16 bits for the network portion and corresponds to the subnet mask 255.255.0.0.
What is a network address?
The network address identifies the subnet itself and is calculated by applying the subnet mask to the IPv4 address.
What is a broadcast address?
The broadcast address is traditionally the final IPv4 address in a subnet and has all host bits set to one.
What is a subnet mask?
A subnet mask identifies which bits of an IPv4 address belong to the network prefix and which belong to the host portion.
What is a wildcard mask?
A wildcard mask is the bitwise inverse of the subnet mask. For example, 255.255.255.0 has the wildcard mask 0.0.0.255.
How many addresses are in a /24?
A /24 IPv4 subnet contains 256 total addresses.
How many traditional usable hosts are in a /24?
A conventional /24 subnet has 254 traditionally usable host addresses after excluding the network and broadcast addresses.
How many addresses are in a /30?
A /30 contains four total IPv4 addresses.
What is a /32?
A /32 represents one individual IPv4 address with no host bits remaining.
Can this calculate private IP ranges?
Yes. The calculator can identify IPv4 addresses belonging to common private ranges such as 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16.
Does this support IPv6?
This tool is intended specifically for IPv4 subnet calculations. IPv6 subnetting should be handled separately because IPv6 addressing works differently.
Are calculations sent to SwiftVecto servers?
No server-side processing is required. IPv4 subnet calculations can be performed directly in your browser.
Things to Know
- This calculator is designed for IPv4 addresses.
- IPv4 addresses contain 32 bits.
- CIDR prefix lengths range from /0 through /32.
- Subnet masks and wildcard masks are calculated directly from the CIDR prefix.
- The traditional usable-host calculation excludes network and broadcast addresses where applicable.
- Special cases such as /31 and /32 should be handled according to their networking semantics rather than blindly subtracting two addresses.
- Private and reserved range classification can be performed entirely in the browser.
- No upload or processing queue is required.
Disclaimer
Subnet calculations should be independently verified before making production routing, firewall, DHCP, VPN or other network configuration changes.
Historical IPv4 classes are included only as informational context and are not a replacement for modern CIDR-based network design.
Special-purpose ranges and specialised network configurations may follow rules different from conventional host-range assumptions.
SwiftVecto does not configure or modify any network device; it only performs subnet calculations.