IP Range Calculator
Calculate CIDR masks, network boundaries, usable hosts, and explore real-time bit distribution and subnet divisions.
Subnet and CIDR calculator
Start IP & End IP Range
32-Bit Binary Map
Subnet Spectrum & Address Bar
256 AddressesSubnet Parameters & MetricsClick any value to copy
CIDR Blocks for Selected IP Range1 CIDR Block
Exact non-overlapping CIDR blocks required to span the provided range:
Subnet Subdivider & Capacity Planner
Split the current network into smaller, equal subnets for VLANs, Kubernetes clusters, or multi-tier architectures.
| Subnet CIDR | Network Address | Usable Host Range | Broadcast Address | Usable Hosts |
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Specialized Subnetting & IP Subtools
Quickly access dedicated calculators for prefix boundaries, address conversions, wildcard masks, route summarization, and VPC subnet design.
IPv4 Range Calculator
Find address boundaries from a prefix.
IPv6 Range Calculator
Find IPv6 prefix boundaries.
IPv4 Subnet Calculator
Calculate subnet details from address and mask.
IPv6 Subnet Calculator
Calculate prefix details and address counts.
CIDR to IP Range Converter
Convert prefixes into start–end ranges.
IP Range to CIDR Converter
Find exact covering CIDR blocks.
IP Address and Mask Calculator
Calculate the corresponding network range.
Network Address Calculator
Find the subnet’s network address.
IPv4 Broadcast Address Calculator
Find broadcast addresses where applicable.
First and Last Address Calculator
Identify a range’s endpoints.
Usable IPv4 Host Range Calculator
Apply the selected subnet-use rules.
Total Address Count Calculator
Count addresses within a prefix.
Usable Host Count Calculator
Account for applicable address reservations.
Host Bits Calculator
Calculate bits available within a prefix.
Network Bits Calculator
Identify the network prefix length.
Host Requirement to Prefix Calculator
Find a prefix meeting capacity requirements.
Prefix to Host Capacity Calculator
Calculate capacity for a specified prefix.
IPv4 /31 Link Calculator
Apply point-to-point addressing rules.
IPv4 /32 Host Route Calculator
Calculate single-address IPv4 prefix details.
IPv6 /127 Link Planner
Divide a parent prefix into address pairs.
IPv6 /128 Address Calculator
Calculate single-address IPv6 prefix details.
CIDR to Subnet Mask Converter
Convert IPv4 prefixes to dotted masks.
Subnet Mask to CIDR Converter
Find prefix length from contiguous masks.
Subnet Mask Validator
Check mask structure and contiguity.
Subnet Mask to Wildcard Converter
Calculate the inverse IPv4 mask.
Wildcard Mask to Subnet Mask Converter
Convert compatible contiguous wildcard masks.
ACL Wildcard Match Calculator
Evaluate address-and-wildcard matching.
ACL Wildcard to CIDR Converter
Express matching addresses as CIDR blocks.
CIDR Validator
Check address and prefix syntax.
IP Address Validator
Check IPv4 or IPv6 address syntax.
IP Range Validator
Check endpoints and address-family consistency.
CIDR Canonicalizer
Normalize prefixes to network boundaries.
Mixed IP Input Parser
Interpret addresses, prefixes, masks, and ranges.
IPv4 Binary Converter
Convert addresses to binary.
IPv4 Decimal Integer Converter
Convert IPv4 addresses to integer values.
Integer to IPv4 Converter
Convert integer values to addresses.
IPv4 Hexadecimal Converter
Convert addresses to hexadecimal.
IPv6 Binary Converter
Display address bits.
IPv6 Integer Converter
Convert IPv6 addresses to integer values.
IPv6 Address Expander
Restore omitted hexadecimal groups.
IPv6 Address Compressor
Shorten address notation.
IPv4-Mapped IPv6 Converter
Construct or decode mapped addresses.
Network and Host ID Calculator
Separate prefix and host portions.
Bitwise Subnet Calculator
Show address-and-mask operations.
IP Address Offset Calculator
Add or subtract address positions.
Address Distance Calculator
Count positions between two addresses.
Nth Address Calculator
Find an address by range offset.
Address Index Calculator
Find an address’s position within a range.
Next Subnet Calculator
Find the following same-sized subnet.
Previous Subnet Calculator
Find the preceding same-sized subnet.
Subnet Boundary Checker
Check alignment to a specified prefix.
IP-in-Range Checker
Test whether an address belongs.
IP-in-Subnet Checker
Test membership within a CIDR block.
Same Subnet Checker
Compare addresses under a selected mask.
Subnet Containment Checker
Test whether one subnet contains another.
Range Overlap Checker
Detect intersecting address ranges.
CIDR Overlap Checker
Detect overlapping network prefixes.
Range Intersection Calculator
Find addresses shared between ranges.
Range Union Calculator
Combine address sets.
Range Difference Calculator
Remove one address set from another.
Range Complement Calculator
Find unallocated addresses within a parent.
Adjacent Range Checker
Identify directly neighboring ranges.
IP Range Merger
Combine overlapping or adjacent intervals.
IP Range Splitter
Divide a range at selected boundaries.
Equal Subnet Splitter
Divide a network into equal prefixes.
Subnet Count Calculator
Count child prefixes within a parent.
Required Subnet Prefix Calculator
Determine prefix length for subnet quantity.
VLSM Calculator
Allocate differently sized subnets.
VLSM Allocation Validator
Check alignment, capacity, and overlaps.
Supernet Calculator
Find a covering parent prefix.
Exact CIDR Aggregator
Merge prefixes without adding addresses.
Route Summary Calculator
Summarize networks and identify included gaps.
Smallest Covering CIDR Calculator
Find one prefix covering a range.
CIDR Coverage Gap Calculator
Identify uncovered addresses between allocations.
Prefix Expansion Calculator
List child prefixes at a selected length.
IPv6 Subnet ID Calculator
Identify subnet bits within a parent.
IPv6 Prefix Allocation Planner
Allocate child prefixes by requested sizes.
IPv6 Prefix Capacity Calculator
Count available child subnets.
IPv6 Address Type Classifier
Identify architectural address types.
Private IPv4 Range Checker
Check membership in private address blocks.
Special-Purpose Address Classifier
Use a selected address registry snapshot.
Legacy IPv4 Class Identifier
Explain historical classful address categories.
DHCP Scope Calculator
Plan allocation boundaries within a subnet.
DHCP Exclusion Calculator
Remove specified addresses and ranges.
DHCP Pool Capacity Calculator
Count addresses available after exclusions.
Static Address Reservation Planner
Allocate entered static address reservations.
Gateway Address Validator
Check an entered gateway against subnet rules.
Duplicate Allocation Checker
Find repeated addresses or overlapping allocations.
VLAN Subnet Planner
Assign prefixes to requested VLAN capacities.
Site Address Allocation Planner
Divide a parent range across sites.
Address Growth Headroom Calculator
Reserve capacity for planned expansion.
Subnet Utilization Calculator
Compare recorded allocations with available capacity.
Free Address Range Finder
Find gaps in entered allocation records.
Next Available Subnet Finder
Find aligned space within a parent.
Allocation Fragmentation Analyzer
Identify scattered free address blocks.
AWS VPC Subnet Capacity Calculator
Account for AWS address reservations.
Custom Cloud Subnet Calculator
Apply entered provider reservation rules.
Multi-Cloud CIDR Overlap Checker
Compare entered cloud network allocations.
VPN Network Overlap Checker
Compare local and remote address spaces.
Longest Prefix Match Calculator
Find the most specific matching route.
Routing Table Coverage Analyzer
Compare entered routes with target ranges.
Firewall CIDR List Optimizer
Consolidate equivalent address sets.
Firewall Address Exclusion Calculator
Subtract exceptions from allowed ranges.
ACL Address Match Tester
Test an address against supplied rules.
IPv4 Reverse DNS Name Generator
Generate address-level reverse lookup names.
IPv6 Reverse DNS Name Generator
Generate nibble-format reverse lookup names.
Reverse DNS Zone Planner
Identify applicable reverse delegation boundaries.
Bounded IP Address List Generator
Enumerate a selected, limited address range.
Random Address Sampler
Sample addresses within supplied ranges.
Batch Subnet Calculator
Calculate details for multiple prefixes.
IP List Deduplicator
Remove repeated addresses.
IP Address Sorter
Sort addresses numerically.
Mixed Range Normalizer
Standardize addresses, intervals, and prefixes.
IP Range Comparison Tool
Compare two address-set lists.
IP Range Change Analyzer
Identify added and removed addresses.
Subnet Table Generator
Create a structured addressing reference.
Network Hierarchy Visualizer
Show parent and child prefix relationships.
Address Allocation Map Generator
Visualize occupied and available blocks.
Subnetting Step Explainer
Show binary and prefix calculations.
Subnetting Practice Generator
Create address-planning exercises.
Subnetting Answer Checker
Check calculated ranges and masks.
IP Plan Importer
Load existing address allocation records.
IP Plan Exporter
Export ranges, prefixes, and allocation details.
IP Range Report Generator
Summarize inputs, calculations, and assumptions.
IPv4 CIDR Reference Cheat Sheet
Quick lookup table for network engineers, cloud architects, and sysadmins.
| CIDR | Netmask | Total Addresses | Usable Hosts | Class Equivalent |
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How IP Range Calculator works
Every result is computed instantly in your browser with exact 32-bit integer math — nothing is uploaded to a server.
Enter an address and prefix
Type any IPv4 address and choose a prefix with the slider, the netmask list, or by pasting CIDR notation such as 10.0.0.0/16 straight into the address field.
The mask is applied bit by bit
The network address is the IP AND the subnet mask, the broadcast address is the network OR the wildcard mask, and the usable host range sits between them.
Read the live visual maps
The 32-bit binary map shows which bits belong to the network and which to hosts, while the spectrum bar shows reserved and usable addresses at a glance.
Plan, convert, and export
Split the block into equal subnets, convert any start–end IP range into the minimal list of CIDR blocks, then copy a summary or download the result as JSON.
IPv4 subnetting basics
What is CIDR?
Classless Inter-Domain Routing (CIDR) replaced the legacy Class A/B/C system in 1993. It uses variable-length subnet masking (VLSM) to allocate IP addresses much more flexibly and prevent IPv4 exhaustion.
Usable Hosts vs Total
Standard subnets reserve 2 addresses: the first as the Network ID (all host bits 0) and the last as the Broadcast ID (all host bits 1). Exception: /31 point-to-point links (RFC 3021) and /32 single hosts.
Private Address Spaces
Defined under RFC 1918: 10.0.0.0/8 (16.7M IPs), 172.16.0.0/12 (1M IPs), and 192.168.0.0/16 (65.5k IPs). They are non-routable on the public internet.
Frequently asked questions
Quick answers about subnet masks, CIDR notation and how this IP range calculator works.
What does an IP range calculator do?
It takes an IPv4 address and a prefix length (CIDR) and works out the full block it belongs to: the network address, broadcast address, first and last usable host, subnet mask, wildcard mask, and how many addresses the block contains.
How do I convert a CIDR block to an IP range?
Enter the address and prefix, for example 10.0.0.0/16. The tool applies the subnet mask and shows the first address (network), the last address (broadcast) and the usable range in between — for 10.0.0.0/16 that is 10.0.0.0 to 10.0.255.255.
How do I convert an IP range to CIDR notation?
Switch to the IP Range to CIDR Converter tab, enter a start and end address, and the tool returns the smallest set of non-overlapping CIDR blocks that exactly covers that range.
How many usable hosts are in a /24 subnet?
A /24 contains 256 addresses. Two are reserved for the network and broadcast addresses, which leaves 254 usable host addresses.
Why do /31 and /32 subnets show no reserved addresses?
A /31 is used for point-to-point links under RFC 3021, so both of its addresses are usable. A /32 identifies a single host, so its only address is the host itself.
What is a wildcard mask?
A wildcard mask is the inverse of the subnet mask — 255.255.255.0 becomes 0.0.0.255. Routers use it in access control lists and OSPF configuration to match a range of addresses.
Are the IP addresses I enter sent to a server?
No. All calculations run locally in your browser with JavaScript, so the addresses and network plans you enter never leave your device.
Does the calculator support IPv6?
Not yet. The calculator currently covers IPv4 subnetting from /0 to /32. If IPv6 support would help you, let us know through the contact page.