network calculator

Professional IPv4 & IPv6 network calculator. Compute CIDR, subnet mask, network/broadcast, first/last usable, private ranges, reverse DNS (in-addr.arpa / ip6.arpa), and more. Built for reliability and accessibility.

network calculator

A precise IPv4/IPv6 subnet tool for engineers, admins, and learners. Enter an address in CIDR notation to get network/broadcast, first & last usable, subnet/wildcard masks (IPv4), reverse DNS pointers, and private/public classification.

IP Version

Choose IPv4 (32-bit) or IPv6 (128-bit).

Address in CIDR

Enter an IP followed by “/prefix”. Examples: 10.0.0.1/8, 172.16.5.10/16, 192.168.1.10/24, 2001:db8::1/64. CIDR prefix ranges: IPv4 (0–32), IPv6 (0–128).

IPv4 Subnet Mask (optional)

Results

General

IP Version: —
Input Address: —
CIDR Prefix: —
Type: —
Private/Reserved: —

Mask / Size

Subnet Mask (v4): —
Wildcard Mask (v4): —
Block Size: —
# of Addresses: —
Usable Hosts (v4): —

Range

Network: —
First Usable: —
Last Usable: —
Broadcast (v4): —

Representations

Reverse DNS: —
IPv6 (Compressed): —
IPv6 (Expanded): —

Data Source & Methodology

Primary references:

IETF RFC 4632 — Classless Inter-Domain Routing (CIDR): IPv4 Addressing Architecture (August 2006).
IETF RFC 791 — Internet Protocol (IPv4) (September 1981).
IETF RFC 4291 — IPv6 Addressing Architecture (February 2006).
IETF RFC 1035 — DNS: in-addr.arpa / ip6.arpa reverse mapping (November 1987).

Tutti i calcoli si basano rigorosamente sulle formule e sui dati forniti da questa fonte.

The Formula Explained

Number of addresses for prefix \( p \):

IPv4: \( N = 2^{(32 - p)} \), IPv6: \( N = 2^{(128 - p)} \)

Network address (integer form):

\( \text{network} = \left\lfloor \dfrac{\text{address}}{2^{(W - p)}} \right\rfloor \times 2^{(W - p)} \) where \( W=32 \) (IPv4) or \( W=128 \) (IPv6).

Broadcast (IPv4): \( \text{broadcast} = \text{network} + N - 1 \)

First/Last usable (IPv4, \(p \le 30\)):

\( \text{first} = \text{network} + 1,\quad \text{last} = \text{broadcast} - 1 \)

Glossary of Variables

Address: The input IP (IPv4 dotted quad or IPv6 hex) with CIDR prefix.
Prefix (p): Bits that identify the network portion (0–32 for IPv4, 0–128 for IPv6).
Subnet Mask: IPv4 mask derived from the prefix (e.g., /24 → 255.255.255.0).
Wildcard Mask: IPv4 complement mask (e.g., 0.0.0.255 for /24).
Network/Broadcast: First and last addresses in the block (broadcast only for IPv4).
Usable Hosts: Number of assignable addresses (IPv4 excludes network & broadcast for /0–/30; special cases noted).

How It Works: A Step-by-Step Example

Example: 192.168.10.42/26

Prefix \(p=26\) ⇒ \(N = 2^{(32-26)} = 64\) addresses.
Mask = 255.255.255.192; Wildcard = 0.0.0.63.
Network = 192.168.10.0 + multiples of 64 ⇒ 192.168.10.0, 64, 128, 192 … The host (42) lies in the 0–63 block ⇒ Network = 192.168.10.0.
Broadcast = Network + 63 = 192.168.10.63.
Usable = 62 addresses: 192.168.10.1 to 192.168.10.62.

FAQ

What prefixes are valid?

IPv4 allows /0 to /32; IPv6 allows /0 to /128. Subnetting typically uses /8–/30 (IPv4) and /32–/64 (IPv6) for routing practicality.

Why are /31 and /32 special in IPv4?

/31 (RFC 3021) can be used for point-to-point without broadcast; /32 denotes a single host route. Usable host count differs from classic “minus 2” rule.

How do private ranges get detected?

The tool checks RFC-defined ranges (e.g., 10/8, 172.16/12, 192.168/16 for IPv4; fc00::/7 for IPv6 unique local).

Why show reverse DNS?

Operations teams use in-addr.arpa/ip6.arpa to verify PTR (reverse) records. We assemble the canonical pointer for the network address.

What if I only enter a mask?

For IPv4 you can paste a mask (e.g., 255.255.255.0) in the helper. The calculator will map it to the nearest valid prefix.

Does the tool validate non-canonical IPv6?

Yes—addresses are normalized to compressed and expanded forms. Invalid compressions or hextet sizes trigger accessible error messages.

Last accuracy review: October 26, 2025

Full original guide (expanded)

Audit: Complete

Formula (LaTeX) + variables + units

This section shows the formulas used by the calculator engine, plus variable definitions and units.

Formula (extracted text)

Number of addresses for prefix \( p \): IPv4: \( N = 2^{(32 - p)} \), IPv6: \( N = 2^{(128 - p)} \) Network address (integer form): \( \text{network} = \left\lfloor \dfrac{\text{address}}{2^{(W - p)}} \right\rfloor \times 2^{(W - p)} \) where \( W=32 \) (IPv4) or \( W=128 \) (IPv6). Broadcast (IPv4): \( \text{broadcast} = \text{network} + N - 1 \) First/Last usable (IPv4, \(p \le 30\)): \( \text{first} = \text{network} + 1,\quad \text{last} = \text{broadcast} - 1 \)

Variables and units

No variables provided in audit spec.

Sources (authoritative):

Home — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/
Lifestyle Everyday — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/lifestyle-everyday
Miscellaneous — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/subcategories/miscellaneous

Changelog

Version: 0.1.0-draft
Last code update: 2026-01-19

0.1.0-draft · 2026-01-19

Initial audit spec draft generated from HTML extraction (review required).
Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
Confirm sources are authoritative and relevant to the calculator methodology.

Verified by Ugo Candido on 2026-01-19
Profile · LinkedIn

network calculator

IP Version

Choose IPv4 (32-bit) or IPv6 (128-bit).

Address in CIDR

Enter an IP followed by “/prefix”. Examples: 10.0.0.1/8, 172.16.5.10/16, 192.168.1.10/24, 2001:db8::1/64. CIDR prefix ranges: IPv4 (0–32), IPv6 (0–128).

IPv4 Subnet Mask (optional)

Results

General

IP Version: —
Input Address: —
CIDR Prefix: —
Type: —
Private/Reserved: —

Mask / Size

Subnet Mask (v4): —
Wildcard Mask (v4): —
Block Size: —
# of Addresses: —
Usable Hosts (v4): —

Range

Network: —
First Usable: —
Last Usable: —
Broadcast (v4): —

Representations

Reverse DNS: —
IPv6 (Compressed): —
IPv6 (Expanded): —

Data Source & Methodology

Primary references:

IETF RFC 4632 — Classless Inter-Domain Routing (CIDR): IPv4 Addressing Architecture (August 2006).
IETF RFC 791 — Internet Protocol (IPv4) (September 1981).
IETF RFC 4291 — IPv6 Addressing Architecture (February 2006).
IETF RFC 1035 — DNS: in-addr.arpa / ip6.arpa reverse mapping (November 1987).

Tutti i calcoli si basano rigorosamente sulle formule e sui dati forniti da questa fonte.

The Formula Explained

Number of addresses for prefix \( p \):

IPv4: \( N = 2^{(32 - p)} \), IPv6: \( N = 2^{(128 - p)} \)

Network address (integer form):

\( \text{network} = \left\lfloor \dfrac{\text{address}}{2^{(W - p)}} \right\rfloor \times 2^{(W - p)} \) where \( W=32 \) (IPv4) or \( W=128 \) (IPv6).

Broadcast (IPv4): \( \text{broadcast} = \text{network} + N - 1 \)

First/Last usable (IPv4, \(p \le 30\)):

\( \text{first} = \text{network} + 1,\quad \text{last} = \text{broadcast} - 1 \)

Glossary of Variables

Address: The input IP (IPv4 dotted quad or IPv6 hex) with CIDR prefix.
Prefix (p): Bits that identify the network portion (0–32 for IPv4, 0–128 for IPv6).
Subnet Mask: IPv4 mask derived from the prefix (e.g., /24 → 255.255.255.0).
Wildcard Mask: IPv4 complement mask (e.g., 0.0.0.255 for /24).
Network/Broadcast: First and last addresses in the block (broadcast only for IPv4).
Usable Hosts: Number of assignable addresses (IPv4 excludes network & broadcast for /0–/30; special cases noted).

How It Works: A Step-by-Step Example

Example: 192.168.10.42/26

Prefix \(p=26\) ⇒ \(N = 2^{(32-26)} = 64\) addresses.
Mask = 255.255.255.192; Wildcard = 0.0.0.63.
Network = 192.168.10.0 + multiples of 64 ⇒ 192.168.10.0, 64, 128, 192 … The host (42) lies in the 0–63 block ⇒ Network = 192.168.10.0.
Broadcast = Network + 63 = 192.168.10.63.
Usable = 62 addresses: 192.168.10.1 to 192.168.10.62.

FAQ

What prefixes are valid?

IPv4 allows /0 to /32; IPv6 allows /0 to /128. Subnetting typically uses /8–/30 (IPv4) and /32–/64 (IPv6) for routing practicality.

Why are /31 and /32 special in IPv4?

/31 (RFC 3021) can be used for point-to-point without broadcast; /32 denotes a single host route. Usable host count differs from classic “minus 2” rule.

How do private ranges get detected?

The tool checks RFC-defined ranges (e.g., 10/8, 172.16/12, 192.168/16 for IPv4; fc00::/7 for IPv6 unique local).

Why show reverse DNS?

Operations teams use in-addr.arpa/ip6.arpa to verify PTR (reverse) records. We assemble the canonical pointer for the network address.

What if I only enter a mask?

For IPv4 you can paste a mask (e.g., 255.255.255.0) in the helper. The calculator will map it to the nearest valid prefix.

Does the tool validate non-canonical IPv6?

Yes—addresses are normalized to compressed and expanded forms. Invalid compressions or hextet sizes trigger accessible error messages.

Last accuracy review: October 26, 2025

Audit: Complete

Formula (LaTeX) + variables + units

This section shows the formulas used by the calculator engine, plus variable definitions and units.

Formula (extracted text)

Number of addresses for prefix \( p \): IPv4: \( N = 2^{(32 - p)} \), IPv6: \( N = 2^{(128 - p)} \) Network address (integer form): \( \text{network} = \left\lfloor \dfrac{\text{address}}{2^{(W - p)}} \right\rfloor \times 2^{(W - p)} \) where \( W=32 \) (IPv4) or \( W=128 \) (IPv6). Broadcast (IPv4): \( \text{broadcast} = \text{network} + N - 1 \) First/Last usable (IPv4, \(p \le 30\)): \( \text{first} = \text{network} + 1,\quad \text{last} = \text{broadcast} - 1 \)

Variables and units

No variables provided in audit spec.

Sources (authoritative):

Home — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/
Lifestyle Everyday — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/lifestyle-everyday
Miscellaneous — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/subcategories/miscellaneous

Changelog

Version: 0.1.0-draft
Last code update: 2026-01-19

0.1.0-draft · 2026-01-19

Initial audit spec draft generated from HTML extraction (review required).
Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
Confirm sources are authoritative and relevant to the calculator methodology.

Verified by Ugo Candido on 2026-01-19
Profile · LinkedIn

network calculator

IP Version

Choose IPv4 (32-bit) or IPv6 (128-bit).

Address in CIDR

Enter an IP followed by “/prefix”. Examples: 10.0.0.1/8, 172.16.5.10/16, 192.168.1.10/24, 2001:db8::1/64. CIDR prefix ranges: IPv4 (0–32), IPv6 (0–128).

IPv4 Subnet Mask (optional)

Results

General

IP Version: —
Input Address: —
CIDR Prefix: —
Type: —
Private/Reserved: —

Mask / Size

Subnet Mask (v4): —
Wildcard Mask (v4): —
Block Size: —
# of Addresses: —
Usable Hosts (v4): —

Range

Network: —
First Usable: —
Last Usable: —
Broadcast (v4): —

Representations

Reverse DNS: —
IPv6 (Compressed): —
IPv6 (Expanded): —

Data Source & Methodology

Primary references:

IETF RFC 4632 — Classless Inter-Domain Routing (CIDR): IPv4 Addressing Architecture (August 2006).
IETF RFC 791 — Internet Protocol (IPv4) (September 1981).
IETF RFC 4291 — IPv6 Addressing Architecture (February 2006).
IETF RFC 1035 — DNS: in-addr.arpa / ip6.arpa reverse mapping (November 1987).

Tutti i calcoli si basano rigorosamente sulle formule e sui dati forniti da questa fonte.

The Formula Explained

Number of addresses for prefix \( p \):

IPv4: \( N = 2^{(32 - p)} \), IPv6: \( N = 2^{(128 - p)} \)

Network address (integer form):

\( \text{network} = \left\lfloor \dfrac{\text{address}}{2^{(W - p)}} \right\rfloor \times 2^{(W - p)} \) where \( W=32 \) (IPv4) or \( W=128 \) (IPv6).

Broadcast (IPv4): \( \text{broadcast} = \text{network} + N - 1 \)

First/Last usable (IPv4, \(p \le 30\)):

\( \text{first} = \text{network} + 1,\quad \text{last} = \text{broadcast} - 1 \)

Glossary of Variables

Address: The input IP (IPv4 dotted quad or IPv6 hex) with CIDR prefix.
Prefix (p): Bits that identify the network portion (0–32 for IPv4, 0–128 for IPv6).
Subnet Mask: IPv4 mask derived from the prefix (e.g., /24 → 255.255.255.0).
Wildcard Mask: IPv4 complement mask (e.g., 0.0.0.255 for /24).
Network/Broadcast: First and last addresses in the block (broadcast only for IPv4).
Usable Hosts: Number of assignable addresses (IPv4 excludes network & broadcast for /0–/30; special cases noted).

How It Works: A Step-by-Step Example

Example: 192.168.10.42/26

Prefix \(p=26\) ⇒ \(N = 2^{(32-26)} = 64\) addresses.
Mask = 255.255.255.192; Wildcard = 0.0.0.63.
Network = 192.168.10.0 + multiples of 64 ⇒ 192.168.10.0, 64, 128, 192 … The host (42) lies in the 0–63 block ⇒ Network = 192.168.10.0.
Broadcast = Network + 63 = 192.168.10.63.
Usable = 62 addresses: 192.168.10.1 to 192.168.10.62.

FAQ

What prefixes are valid?

IPv4 allows /0 to /32; IPv6 allows /0 to /128. Subnetting typically uses /8–/30 (IPv4) and /32–/64 (IPv6) for routing practicality.

Why are /31 and /32 special in IPv4?

/31 (RFC 3021) can be used for point-to-point without broadcast; /32 denotes a single host route. Usable host count differs from classic “minus 2” rule.

How do private ranges get detected?

The tool checks RFC-defined ranges (e.g., 10/8, 172.16/12, 192.168/16 for IPv4; fc00::/7 for IPv6 unique local).

Why show reverse DNS?

Operations teams use in-addr.arpa/ip6.arpa to verify PTR (reverse) records. We assemble the canonical pointer for the network address.

What if I only enter a mask?

For IPv4 you can paste a mask (e.g., 255.255.255.0) in the helper. The calculator will map it to the nearest valid prefix.

Does the tool validate non-canonical IPv6?

Yes—addresses are normalized to compressed and expanded forms. Invalid compressions or hextet sizes trigger accessible error messages.

Last accuracy review: October 26, 2025

Audit: Complete

Formula (LaTeX) + variables + units

This section shows the formulas used by the calculator engine, plus variable definitions and units.

Formula (extracted text)

Number of addresses for prefix \( p \): IPv4: \( N = 2^{(32 - p)} \), IPv6: \( N = 2^{(128 - p)} \) Network address (integer form): \( \text{network} = \left\lfloor \dfrac{\text{address}}{2^{(W - p)}} \right\rfloor \times 2^{(W - p)} \) where \( W=32 \) (IPv4) or \( W=128 \) (IPv6). Broadcast (IPv4): \( \text{broadcast} = \text{network} + N - 1 \) First/Last usable (IPv4, \(p \le 30\)): \( \text{first} = \text{network} + 1,\quad \text{last} = \text{broadcast} - 1 \)

Variables and units

No variables provided in audit spec.

Sources (authoritative):

Home — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/
Lifestyle Everyday — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/lifestyle-everyday
Miscellaneous — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/subcategories/miscellaneous

Changelog

Version: 0.1.0-draft
Last code update: 2026-01-19

0.1.0-draft · 2026-01-19

Initial audit spec draft generated from HTML extraction (review required).
Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
Confirm sources are authoritative and relevant to the calculator methodology.

Verified by Ugo Candido on 2026-01-19
Profile · LinkedIn

Formulas

(Formulas preserved from original page content, if present.)

Version 0.1.0-draft

Citations

Add authoritative sources relevant to this calculator (standards bodies, manuals, official docs).

Changelog

0.1.0-draft — 2026-01-19: Initial draft (review required).

network calculator

network calculator