Skip to main content
IP Range CalculatorPRO
Diagnostics, Generators & UtilitiesInstant Client-Side Tool

IP Range Change Analyzer

Identify added and removed addresses.

IP Range Change Analyzer: 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 Diagnostics, Generators & UtilitiesAll Tools

IPv4 Reverse DNS Name Generator

Generate address-level 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.

How IP Range Change Analyzer Works?

The IP Range Change Analyzer works by comparing an old version and a new version of an address list and reporting the addresses added, the addresses removed, and the addresses unchanged.

  1. Paste the old version

    Enter the previous list, such as last month's provider ranges.

  2. Paste the new version

    Enter the current list.

  3. Compute the changes

    Added = New − Old, Removed = Old − New, and Unchanged = Old ∩ New.

  4. Summarize

    The analyzer reports each group as CIDR blocks with address counts and the net change.

IP Range Change Analyzer Formula

The IP Range Change Analyzer formula is Added = New − Old, Removed = Old − New, and Net Change = |Added| − |Removed|.

Added

New − Old

Space that appeared.

Removed

Old − New

Space that disappeared.

Unchanged

Old ∩ New

Space in both versions.

Net change

|Added| − |Removed|

Growth or shrinkage in addresses.

Worked example: provider list update

Old: 52.10.0.0/16, 54.20.0.0/15, 3.5.0.0/19
New: 52.10.0.0/16, 54.20.0.0/16, 3.5.0.0/18, 18.30.0.0/20
Added   = 3.5.32.0/19, 18.30.0.0/20
Removed = 54.21.0.0/16
Net     = −53,248 addresses

IP Range Change Analyzer Conversion Table

The IP Range Change Analyzer conversion table summarizes the change between the old and new provider lists in the worked example.

ChangeCIDR BlocksAddresses
Added3.5.32.0/19, 18.30.0.0/2012,288
Removed54.21.0.0/1665,536
Unchanged3.5.0.0/19, 52.10.0.0/16, 54.20.0.0/16139,264

What is IP Range Change Analyzer?

The IP Range Change Analyzer is a tool that identifies which addresses were added and which were removed between 2 versions of an address list.

Cloud providers, CDNs, and SaaS vendors update their published IP ranges regularly. AWS publishes changes to ip-ranges.json several times per week. Firewall teams need the exact delta, not 2 long lists to read side by side.

The analyzer works on address space, not on text lines. A /15 replaced by a /16 shows up as 1 removed /16, not as 1 removed line and 1 added line.

What are the uses of IP Range Change Analyzer?

There are 4 main uses of the IP Range Change Analyzer, including provider list tracking, change review, and incident investigation.

  • Tracking provider list updates

    Weekly diffs of cloud and CDN ranges drive firewall updates.

  • Reviewing firewall changes

    The analyzer shows the exact access added or removed by a change request.

  • Investigating incidents

    Comparing allow-lists before and after an outage reveals removed space.

  • Auditing IPAM history

    Monthly snapshots show how the address plan changed.