# Subnet CIDR Pro — IPv4, CIDR & VLSM Calculator

> Offline IPv4 subnet calculator and VLSM planner for network engineers. (iPhone/iPad app by 超 张.)

- Source: https://appshunter.io/ios/app/subnet-cidr-pro/id6816397989 (this page in markdown: same URL + `.md`)
- Developer: [超 张](https://appshunter.io/developer/1895478141)
- Category: Productivity, Utilities
- Price: Free
- Rating: 5.00/5 from 1 App Store ratings
- Age rating: 4+
- Requires: iOS 16.0 · 1 MB
- Languages: American English
- Released: 2026-09-30
- Data updated: 2026-10-04
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/subnet-cidr-pro/id6816397989/reviews.md

## What is Subnet CIDR Pro?

Subnet CIDR Pro is a clean, lightning-fast, and precise IPv4 subnet calculator and visual VLSM planner designed for network engineers, sysadmins, cloud architects, and IT students.

Built natively for iOS with a focus on speed and clarity, it eliminates the guesswork from IP allocation and network boundary calculations. Whether you are configuring router interfaces in the datacenter, planning VPC subnets in AWS/Azure, or studying for Cisco CCNA/CCNP certifications, Subnet CIDR Pro delivers instant, accurate results.

KEY FEATURES:

1. Instant IPv4 & CIDR Calculation
• Real-time calculations as you type IP address or adjust CIDR prefix (/0 to /32).
• Full breakdown: Subnet Mask, Wildcard Mask, Network Address, Broadcast Address, First/Last Usable Host, and Total Usable Hosts.
• RFC 3021 Compliant: Correct handling for /31 point-to-point links (2 usable hosts) and /32 single host routing.
• Binary Visualization: Clear binary breakdown highlighting network and host bit boundaries.
• One-tap copying for any calculated value or complete CIDR summary.

2. Visual VLSM Subnet Planner
• Automatically allocate Variable Length Subnet Masks (VLSM) from any parent IPv4 block.
• Add custom subnet requirements with host counts and descriptive names.
• Optimal subnet block sorting to eliminate IP space fragmentation.
• Detect allocation overflows and subnet overlaps instantly.
• Export or copy your complete allocation table with one tap.

3. Complete CIDR & Mask Reference
• Interactive /0 to /32 quick-lookup cheat sheet.
• Displays subnet masks, wildcard masks, total addresses, and usable host counts at a glance.
• Instant search to quickly verify subnet boundaries.

PROFESSIONAL & PRIVACY-FIRST:
• 100% Offline & Self-Contained: All calculations run locally on your device.
• Zero Ads & Zero Tracking: No analytics, no third-party SDKs, and no telemetry.
• No In-App Purchases & No Subscriptions: One-time purchase unlocks lifetime complete access.
• Native Dark Mode UI optimized for field diagnostics and server room environments.

LEGAL & PRIVACY:
• Privacy Policy: https://subnet.opshome.run/privacy/
• Terms of Use: https://subnet.opshome.run/terms/
• Support & Feedback: https://subnet.opshome.run/support/

Designed with pride by OpsHome for network practitioners who value precision, simplicity, and privacy.

## Key features

- Instant IPv4 & CIDR calculation
- Visual VLSM subnet planner
- Complete CIDR & mask reference
- Offline operation
- No ads or tracking
- One-tap copying


## Frequently asked questions about Subnet CIDR Pro

### What is Subnet CIDR Pro?

Subnet CIDR Pro is a native iOS application designed for network engineers and IT professionals. It provides fast and accurate IPv4 subnet calculations, visual VLSM planning, and a comprehensive CIDR reference tool.

### Does Subnet CIDR Pro have ads?

No, Subnet CIDR Pro is completely ad-free. The app is designed with a privacy-first approach and contains zero ads, zero tracking, and zero telemetry.

### How much does Subnet CIDR Pro cost?

Subnet CIDR Pro is a one-time purchase. This unlocks lifetime access to all features without any subscriptions or in-app purchases.

### Can I use Subnet CIDR Pro offline?

Yes, Subnet CIDR Pro is 100% offline and self-contained. All calculations run locally on your device, ensuring functionality without an internet connection.

### What devices does Subnet CIDR Pro support?

Subnet CIDR Pro is currently supported on iPhone devices. It features a native dark mode UI optimized for various environments.

### How often is Subnet CIDR Pro updated?

The app was last updated on October 1, 2026, with version 1.0. While specific update frequency isn't detailed, the developer is committed to providing a reliable tool.

### What are the benefits of the visual VLSM planner in Subnet CIDR Pro?

The visual VLSM planner automatically allocates Variable Length Subnet Masks from any parent IPv4 block. It allows for custom subnet requirements, optimal sorting to prevent fragmentation, and instant detection of overflows or overlaps.

### Is Subnet CIDR Pro suitable for beginners?

Yes, Subnet CIDR Pro is designed for IT students and professionals alike. Its clean interface, instant calculations, and clear binary visualization make complex subnetting concepts more accessible.

## Version history (last 1 release)

### 1.0 — 2026-10-01

No release notes.

## More apps by 超 张

- [OpsHome NOC](https://appshunter.io/ios/app/opshome-noc/id6763890679)
- [SSL Certificate Monitor](https://appshunter.io/ios/app/ssl-certificate-monitor/id6786519365)
- [WiFi HealthCheck](https://appshunter.io/ios/app/wifi-healthcheck/id6791147190)
- [Domain Checker: DNS & SSL](https://appshunter.io/ios/app/domain-checker-dns-and-ssl/id6792293532)
- [FortiGate NOC Monitor](https://appshunter.io/ios/app/fortigate-noc-monitor/id6796713266)

All apps by 超 张: https://appshunter.io/developer/1895478141

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-04.*