PrefixForge: IPv4 Subnet Tools
CIDR plans, masks & addresses
$3.99 · Designed for iPad. Not verified for macOS.
Know every boundary: calculate IPv4 CIDR blocks, split subnets, inspect binary masks and keep named network plans offline.
Plan IPv4 networks with clear CIDR arithmetic and saved local notes. PrefixForge is an offline tool for developers, network learners and anyone organizing an address plan.
• Enter an IPv4 host or network with a /0–/32 prefix. See the normalized network, subnet mask, directed broadcast, wildcard mask, address range and host capacity.
• Understand /31 point-to-point endpoints and /32 host routes with explicit explanations instead of misleading network/broadcast reservations.
• Split a parent network into equal-size child subnets, with up to 256 rows. Inspect each child’s boundaries or share the subnet table as text.
• View binary addresses and masks, plus the count of network and host bits.
• Check whether an address lies inside a CIDR block.
• Classify the input address against common private, shared, link-local, loopback, documentation and other special ranges.
• Save named network plans with purpose and reservation notes. Edit, delete and export them as text.
• Consult an offline table of all 33 prefix lengths and original explanations of CIDR planning.
Works on iPhone and iPad with no account, ads, analytics, tracking or in-app purchases. Calculations and saved plans work entirely offline.
PrefixForge calculates address boundaries; it does not discover devices, scan networks, test connectivity, configure equipment, or check address availability. Host counts describe conventional arithmetic capacity and may not equal assignable capacity in special-purpose ranges. The common-range table is not exhaustive and is not a live allocation or routability database. IPv6, VLSM optimization and DNS lookup are not included.
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The developer, Bryl Kezter Lim, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Bryl Kezter Lim
- Size
- 599 KB
- Category
- Developer Tools
- Compatibility
Requires iOS 18.0 or later.
- iPhone
Requires iOS 18.0 or later. - iPad
Requires iPadOS 18.0 or later. - Mac
Requires macOS 15.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 2.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © 2026 Bryl Lim
