Skip to main content
IP Range CalculatorPRO
Conversion & EncodingInstant Client-Side Tool

CIDR to IP Range Converter

Convert prefixes into start–end ranges.

CIDR to IP Range Converter: inputs and results

Enter an IP address, CIDR prefix, or range. Then check its first and last address below.

Quick presets:

Calculated Boundaries & ParametersReady

Network Address192.168.1.0
Broadcast Address192.168.1.255
First Usable Host192.168.1.1
Last Usable Host192.168.1.254
Subnet Mask255.255.255.0
Wildcard Mask0.0.0.255
Total Addresses256
Usable Host Range254

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.
Open Full Interactive Suite

Related Conversion & EncodingAll Tools

IP Range to CIDR Converter

Find exact covering CIDR blocks.

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.

How CIDR to IP Range Converter Works?

This tool works by turning each CIDR prefix into a start address and an end address, then printing both in dotted and integer form for range-based systems.

  1. Paste 1 or more CIDR blocks

    Enter blocks such as 172.20.0.0/14, one per line.

  2. Align each block

    The converter clears the host bits, so an entry such as 172.21.9.9/14 still starts at 172.20.0.0.

  3. Compute the end

    The end equals the start plus 2^(32 − p) − 1.

  4. Output the ranges

    Each line becomes start – end, with integer values for databases and SIEM queries.

CIDR to IP Range Converter Formula

The formula is Range = [N, N + 2^(32 − p) − 1], where N is the aligned network address.

Start

N = IP AND Mask(p)

Aligned block start.

End

N + 2^(32−p) − 1

Last address in the block.

Integer start

o1×16,777,216 + o2×65,536 + o3×256 + o4

Dotted to integer.

Range length

2^(32 − p)

Addresses between start and end, inclusive.

Worked example: 172.20.0.0/14

Block size = 2^18 = 262,144 = 4 × /16
Start = 172.20.0.0       (integer 2,886,991,872)
End   = 172.23.255.255   (integer 2,887,254,015)
Range = 172.20.0.0 – 172.23.255.255

CIDR to IP Range Converter Conversion Table

The table turns 10 CIDR blocks into start–end ranges, with the integer value of both endpoints.

CIDRStart IPEnd IPStart IntegerEnd Integer
10.0.0.0/1610.0.0.010.0.255.255167,772,160167,837,695
10.0.128.0/1710.0.128.010.0.255.255167,804,928167,837,695
172.20.0.0/14172.20.0.0172.23.255.2552,886,991,8722,887,254,015
192.168.100.0/22192.168.100.0192.168.103.2553,232,261,1203,232,262,143
203.0.113.0/25203.0.113.0203.0.113.1273,405,803,7763,405,803,903
198.51.100.128/26198.51.100.128198.51.100.1913,325,256,8323,325,256,895
192.0.2.16/28192.0.2.16192.0.2.313,221,226,0003,221,226,015
100.64.0.0/12100.64.0.0100.79.255.2551,681,915,9041,682,964,479
10.250.0.0/2010.250.0.010.250.15.255184,156,160184,160,255
172.16.254.0/23172.16.254.0172.16.255.2552,886,794,7522,886,795,263

What is CIDR to IP Range Converter?

The CIDR to IP Range Converter is a tool that converts CIDR prefixes into explicit start and end IP addresses. 10.0.128.0/17 becomes 10.0.128.0 – 10.0.255.255.

CIDR is compact, but many systems store and compare addresses as intervals: database tables with start and end columns, geolocation files, and firewall range objects. The converter handles a whole list in one pass.

The integer columns make the output ready for SQL BETWEEN queries, which compare numbers far faster than dotted strings.

What are the uses of CIDR to IP Range Converter?

There are 5 main uses of the CIDR to IP Range Converter, including bulk firewall imports, SQL range tables, and vendor allow-lists.

  • Importing ranges into firewalls

    Firewalls with range objects need start and end values for each CIDR in a vendor list.

  • Filling SQL range tables

    The integer columns load directly into ip_start and ip_end fields.

  • Converting cloud provider lists

    AWS and Google publish address lists in CIDR form. The converter turns them into ranges.

  • Building spreadsheet lookups

    Spreadsheets use numeric ranges for VLOOKUP-style address matching.

  • Explaining CIDR to non-engineers

    Plain ranges show exactly which addresses a prefix covers.