IP Range Validator
Check endpoints and address-family consistency.
IP Range Validator: inputs and results
Enter an IP address, CIDR prefix, or range. Then check its first and last address below.
Calculated Boundaries & ParametersReady
Key Capabilities
- •100% Client-Side: Zero telemetry or server latency.
- •RFC Compliant: Exact 32-bit and 128-bit integer precision.
- •Quick Copy: Instant access to CIDR, mask, and range bounds.
- •Cross-Platform: Works on desktop, tablet, and mobile browsers.
Related IPv4 Subnetting & RangeAll Tools
IPv4 Range Calculator
Find address boundaries from a prefix.
IPv4 Subnet Calculator
Calculate subnet details from address and mask.
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.
How IP Range Validator Works?
The IP Range Validator works by parsing the start and end address, confirming both belong to the same address family, and confirming that the start is less than or equal to the end.
Split the range
The validator splits
10.0.0.10 – 10.0.0.200at the dash into a start and an end.Validate each endpoint
Each endpoint must be a valid IPv4 or IPv6 address on its own.
Check family consistency
An IPv4 start with an IPv6 end fails, since the 2 families use different number spaces (32-bit and 128-bit).
Check order and size
The validator converts both endpoints to integers, confirms
start ≤ end, and returns the range size.
IP Range Validator Formula
The IP Range Validator formula is Valid = valid(start) AND valid(end) AND family(start) = family(end) AND int(start) ≤ int(end).
Order rule
int(start) ≤ int(end)A reversed range has no addresses.
Family rule
family(start) = family(end)IPv4 with IPv4, IPv6 with IPv6.
Range size
Size = int(end) − int(start) + 1Counts both endpoints.
CIDR fit
Exact = (Size is 2^n) AND (start mod Size = 0)True when the range equals one CIDR block.
Worked example: 192.168.10.0 – 192.168.10.127
start = 3,232,238,080 end = 3,232,238,207 Both IPv4 ✓ start ≤ end ✓ Size = 207 − 80 + 1 = 128 = 2^7 start mod 128 = 0 → exact CIDR 192.168.10.0/25
IP Range Validator Conversion Table
The IP Range Validator conversion table shows 10 sample ranges with the validation result, the range size, and the CIDR blocks that cover each valid range.
| Start | End | Result | Size | CIDR Blocks |
|---|---|---|---|---|
| 192.168.10.0 | 192.168.10.127 | Valid | 128 | 192.168.10.0/25 |
| 10.0.0.10 | 10.0.0.200 | Valid | 191 | 8 blocks |
| 172.16.0.0 | 172.16.255.255 | Valid | 65,536 | 172.16.0.0/16 |
| 10.0.0.50 | 10.0.0.10 | Invalid: start after end | — | — |
| 192.168.1.1 | 192.168.1.1 | Valid | 1 | 192.168.1.1/32 |
| 203.0.113.0 | 203.0.114.255 | Valid | 512 | 203.0.113.0/24, 203.0.114.0/24 |
| 198.51.100.7 | 198.51.100.12 | Valid | 6 | 198.51.100.7/32, 198.51.100.8/30, 198.51.100.12/32 |
| 10.0.0.1 | 2001:db8::1 | Invalid: mixed families | — | — |
| 10.0.0.256 | 10.0.1.10 | Invalid: octet above 255 | — | — |
| 100.64.0.0 | 100.127.255.255 | Valid | 4,194,304 | 100.64.0.0/10 |
What is IP Range Validator?
The IP Range Validator is a tool that confirms whether a start–end address range is well formed: both endpoints valid, both in the same address family, and the start not after the end.
Ranges appear in firewall objects, DHCP pools, geolocation files, and threat feeds. A reversed range such as 10.0.0.50 – 10.0.0.10 matches nothing, and a range that mixes IPv4 and IPv6 cannot exist. The IP Range Validator catches both errors before import.
The validator reports the size of every valid range and whether the range lines up with a single CIDR block. 192.168.10.0 – 192.168.10.127 equals 192.168.10.0/25, and 10.0.0.10 – 10.0.0.200 needs several blocks.
What are the uses of IP Range Validator?
There are 5 main uses of the IP Range Validator, including firewall object checks, DHCP pool checks, and data feed cleanup.
Checking firewall range objects
Range objects with reversed endpoints fail silently on some firewalls. The validator catches the order error first.
Verifying DHCP pool ranges
DHCP servers refuse pools whose start comes after the end. The validator checks pool ranges before configuration.
Cleaning threat intelligence feeds
Feeds sometimes contain malformed ranges. The validator drops lines with octets above 255 or mixed families.
Validating spreadsheet imports
Address plans in Excel or CSV files often carry typos. The validator checks each start–end row.
Converting ranges for routers
Routers accept CIDR blocks only. The validator lists the blocks for each valid range.