# CIDR — CIDR Subnet calculator > IPv4 subnet calculator for IP address ranges, CIDR notation, and bit notation. (iPhone/iPad app by ao-system, Inc..) - Source: https://appshunter.io/ios/app/cidr/id1564239813 (this page in markdown: same URL + `.md`) - Developer: [ao-system, Inc.](https://appshunter.io/developer/1338624340) - Category: Utilities, Business - Price: Free with in-app purchases - Rating: 5.00/5 from 1 App Store ratings - Age rating: 4+ - Requires: iOS 15.6 · 23 MB - Languages: English - Released: 2021-04-23 - Data updated: 2026-06-30 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/cidr/id1564239813/reviews.md ## What is CIDR? Calculate the IP address range from the IP address and subnet mask. It can be used to calculate IPv4 addresses, including prefix display, number of address ranges, and bit notation. CIDR calculation, when you want to check CIDR notation quickly. To convert subnet mask to CIDR notation. It can also be used as a quick reference table for subnet masks. Bit notation is also available, so it is suitable for learning IPv4. ## Key features - IP address range calculation - Subnet mask to CIDR conversion - IPv4 prefix display - Number of address ranges - Bit notation display - Quick reference table ## Pricing and in-app purchases Base price: Free. **One-time purchases** | Purchase | Price | Type | | --- | --- | --- | | Remove Ads | $1.99 | one-time | ## Frequently asked questions about CIDR ### What is CIDR used for? CIDR (Classless Inter-Domain Routing) is used to represent IP addresses and their associated network prefixes more efficiently than traditional classful addressing. CIDR helps in IP address allocation and routing. ### Does CIDR support IPv6? Based on the provided description, CIDR focuses on IPv4 calculations. It details features like IPv4 prefix display and bit notation for IPv4 addresses. ### How accurate is CIDR's subnet mask conversion? The app is designed to accurately convert subnet masks to CIDR notation and calculate IP address ranges. It is rated 5.0 stars from 1 rating, indicating high user satisfaction with its functionality. ### Is CIDR suitable for learning IPv4? Yes, the app explicitly states it can be used for learning IPv4, offering bit notation and clear calculations of address ranges and prefixes. ### What devices can I use CIDR on? CIDR is available for iPhone, iPad, and iPod devices, making it accessible for users across the Apple ecosystem. ### How often is CIDR updated? The latest version is 2.11.0, and the last update was on June 21, 2026. This indicates a recent update, suggesting ongoing development and maintenance. ### What is the age rating for CIDR? CIDR has an age rating of 4+, meaning it is suitable for users of all ages and contains no mature content. ### Does CIDR have ads? No, the application does not contain advertisements. It is a free utility without any ad-supported elements. ## Version history (last 5 releases) ### 2.11.0 — 2026-06-21 Added an option to remove ads. Improved the app to start smoothly without stopping, even if the network connection is unstable at startup. ### 2.9.3 — 2026-05-28 Improved overall stability and performance. ### 2.9.0 — 2026-05-18 Updated the Consent Management Platform (CMP). ### 2.8.0 — 2026-03-04 Added a button to the Settings page to open the App Store. ### 2.7.0 — 2026-02-22 You can now zoom in with a double-tap. Long-press to copy is now supported. ## Apps similar to CIDR | App | Rating | Price | Category | | --- | --- | --- | --- | | [About Subnet Mask](https://appshunter.io/ios/app/about-subnet-mask/id1662782439) | 5.0 (1) | Free | Utilities | | [Remote Desktop Manager](https://appshunter.io/ios/app/remote-desktop-manager/id1039961293) | 3.8 (96) | Free | Utilities | | [CIDR Calc](https://appshunter.io/ios/app/cidr-calc/id1565667811) | 5.0 (1) | Free | Utilities | | [Network Helper](https://appshunter.io/ios/app/network-helper/id1155641373) | — | Free | Utilities | | [Subnet Mask Calc](https://appshunter.io/ios/app/subnet-mask-calc/id406375326) | 2.3 (22) | Free | Utilities | | [IPv4 Subnet Calculator](https://appshunter.io/ios/app/ipv4-subnet-calculator/id6446788822) | 5.0 (3) | Free | Utilities | ## More apps by ao-system, Inc. - [奥多摩ウォーキングマップ](https://appshunter.io/ios/app/id1453854955) - [Coin toss. Two sides of a coin](https://appshunter.io/ios/app/coin-toss-two-sides-of-a-coin/id1559344863) - [Wheel Lottery Machine](https://appshunter.io/ios/app/wheel-lottery-machine/id1559502572) - [Bingo Machine](https://appshunter.io/ios/app/bingo-machine/id1561300296) - [Roulette machine](https://appshunter.io/ios/app/roulette-machine/id1561612282) - [Fortune slip](https://appshunter.io/ios/app/fortune-slip/id1561769646) All apps by ao-system, Inc.: https://appshunter.io/developer/1338624340 ## Related topics [akira ohmachi](https://appshunter.io/ios/topics/akira-ohmachi) --- *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 2026-06-30.*