Subnet CIDR Pro
IPv4, CIDR & VLSM Calculator
$1.99 · Designed for iPad. Not verified for macOS.
Fast IPv4 subnet calculator and VLSM planner for network engineers. Calculate CIDRs, split networks, inspect binary bits, and export clean CSVs offline.
Subnet CIDR Pro is a focused, offline-first network calculator and VLSM planner built for network engineers, sysadmins, homelab users, and IT students.
From quick /30 interface checks to full multi-VLAN allocation plans, get accurate IPv4 subnetting and address tooling directly on your iPhone and iPad—with zero tracking, zero ads, and 100% local calculation.
IPv4 & CIDR CALCULATOR
• Full Range Support: Calculate any prefix from /0 to /32
• Essential Telemetry: Network, broadcast, subnet mask, wildcard mask, and usable host ranges
• Host Capacity: Instant breakdown of total addresses vs. usable host capacity
• Modern Link Handling: Full support for /31 point-to-point links (RFC 3021) and /32 host routes
• Binary Inspection: Visualize network vs. host bits in clear binary layout
• Mask Conversion: Seamless conversion between CIDR prefixes, subnet masks, and wildcard masks
• One-Tap Copy: Copy individual values or complete formatted network summaries
VLSM NETWORK PLANNING
• Requirement-Driven Allocation: Subnet a parent IPv4 block based on exact host requirements
• VLAN & Naming: Assign custom network labels and VLAN IDs per subnet
• Growth Headroom: Configurable growth reserve percentage per allocation
• Gateway Reservation: Optional automatic reservation for default gateway addresses
• Space Optimization: View allocated CIDRs alongside remaining unallocated blocks
• Overflow Warnings: Instant alerts when requirements exceed parent network capacity
ADDRESS TOOLS & IP MATH
• Subnet Compare: Test two subnets for containment, overlap, equality, or isolation
• IP Membership: Verify instantly whether an IPv4 address belongs to a target network
• Range to CIDR: Convert arbitrary start/end IP ranges into minimal exact CIDR blocks
• Subnet Splitting: Break down any network into equal-sized child subnets
• Supernetting: Summarize adjacent or overlapping subnets into clean aggregation blocks
PROJECT WORKSPACE & EXPORT
• Project History: Save named planning projects, reopen, rename, or duplicate anytime
• Auto-Save: Automatically preserves your current planning draft
• Data Export: Export complete subnet plans and available address blocks as CSV
• Clipboard Sharing: One-tap copy for formatted plain-text documentation
CIDR QUICK REFERENCE TABLE
• Interactive reference matrix for all prefixes (/0 to /32)
• Searchable by prefix, dotted-decimal mask, wildcard mask, or usable host count
• Fast reference copying for switch and firewall configuration
DESIGNED FOR iOS & iPadOS
• High-contrast dark interface tailored for server rooms and night operations
• Adaptive iPad workspace: side-by-side inputs, live results, and wide allocation tables
• Localized in 13 languages: English, Simplified & Traditional Chinese, German, French, Japanese, Korean, Italian, Spanish, Brazilian Portuguese, Arabic, Dutch, and Turkish
100% OFFLINE & PRIVATE
• Calculations run purely on your device
• No account required, no telemetry SDKs, no ads, and no in-app purchases
Terms of Use: https://subnet.opshome.run/terms/
Privacy Policy: https://subnet.opshome.run/privacy/
Support: https://subnet.opshome.run/support/
Ratings & Reviews
1. Enhanced IPv4 subnet planning with VLSM allocation, growth planning, and gateway reservations.
2. Improved CIDR tools for subnet splitting, aggregation, range-to-CIDR conversion, and subnet relationship analysis.
3. Improved remaining CIDR calculations to help identify available address space.
4. Refined saved plans, calculation history, favorites, and CSV export.
5. Added support for 13 languages with improved localization and language switching.
6. Improved the iPad experience and added local data management options.
7. Fixed language display issues and improved overall stability.
The developer, 超 张, 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
- 超 张
- Size
- 2.2 MB
- Category
- Productivity
- Compatibility
Requires iOS 16.0 or later.
- iPhone
Requires iOS 16.0 or later. - iPad
Requires iPadOS 16.0 or later. - Mac
Requires macOS 13.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
English and 12 more
- English, Arabic, Dutch, French, German, Italian, Japanese, Korean, Portuguese, Simplified Chinese, Spanish, Traditional Chinese, Turkish
- Age Rating
4+
- 4+
- Copyright
- © 2026 Zhang Chao
