IP Calculator

Analyze IPv4 class, binary/hex, integer format, and reverse PTR notation
This free online ip calculator runs in your browser and is part of our Calculators collection.

IP Calculator

Analyze IPv4 addresses with class, binary form, integer value, and reverse DNS notation.

What this helps with

  • Understand IPv4 classes and default mask concepts
  • Convert dotted decimal to binary and integer formats
  • Identify private, loopback, multicast, and reserved ranges
  • Generate reverse lookup notation for DNS PTR zones
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Instant In-Browser Execution Runs locally in JavaScript without wait times or server delays.
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100% Privacy & Security Your inputs and files are never stored or logged on remote servers.
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Cross-Device Responsive Fully optimized for mobile smartphones, tablets, and desktop displays.
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100% Free Forever No subscription fees, no signups, and no software installations.

How to Use the Online IP Calculator

1 Enter IPv4 Address

Type any standard 32-bit dotted-decimal IPv4 address (e.g. `192.168.1.100` or `172.217.16.206`).

2 Inspect IPv4 Class & Address Type

Review the traditional address class (Class A, B, C, D Multicast, or E Experimental) and address scope (Public or RFC 1918 Private).

3 View Multiple Computational Representations

Inspect the IP converted simultaneously into 32-bit Binary, Hexadecimal, and Decimal Integer format.

4 Inspect Reverse DNS Notation

View the formatted `in-addr.arpa` pointer notation used for reverse DNS PTR lookups.

Frequently Asked Questions

Common questions about using this free online ip calculator.

How is an IPv4 address converted to a 32-bit integer? ▾
An IPv4 address consists of 4 octets (`a.b.c.d`). The 32-bit integer is calculated as: `(a × 2^24) + (b × 2^16) + (c × 2^8) + d`. For example, `127.0.0.1` equals `2,130,706,433`.
What are the classic IPv4 address classes? ▾
Class A: 1.0.0.0 to 126.255.255.255 (leading bit `0`); Class B: 128.0.0.0 to 191.255.255.255 (leading bits `10`); Class C: 192.0.0.0 to 223.255.255.255 (leading bits `110`); Class D: 224.0.0.0 to 239.255.255.255 (Multicast); Class E: 240.0.0.0 to 255.255.255.255 (Experimental/Reserved).
What is the reverse DNS format `in-addr.arpa`? ▾
In reverse DNS queries, IP octets are reversed and appended with `.in-addr.arpa` (e.g., `192.0.2.1` becomes `1.2.0.192.in-addr.arpa`), allowing DNS servers to look up PTR domain records hierarchically.
What is the difference between Public and Private IPv4 addresses? ▾
Private IP addresses (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) are reserved for home and internal office networks and cannot be routed across the public internet. Public IPs are globally unique and routable.

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