# Free Subnet Calculator - Link: https://dbr-soft.com/subnet-calculator/ - Published: 2026-10-29T22:18:47+00:00 - Author: David Botero #### Smarter Network Planning Starts Here A well-planned network is the foundation of every modern business. It carries your email, cloud applications, video calls, phone system, cameras, and the devices your team depends on every day. Yet many networks are built by guesswork: too little bandwidth, not enough switch ports, weak Wi-Fi coverage, or an IP plan that can’t grow. The DBR Soft Networking Calculator gives you quick, practical answers to the questions that come up in every network project, so you can plan with real numbers before you spend a dollar on equipment. ## Free IPv4 Subnet Calculator Calculate network ranges, subnet masks, broadcast addresses and usable host counts from a CIDR network. Network (CIDR) Subnet prefix Traditional host counts exclude network and broadcast addresses, except /31 point- to-point links (2 usable) and /32 routes (1 address). Display cap: 4,096 rows. ## VLSM Subnet Planner Enter a parent IPv4 network and the host requirement for each segment. The planner allocates the largest subnets first. Parent network Segment nameRequired hosts Segment nameRequired hosts ## Reverse Subnet Lookup Enter an IPv4 address and CIDR prefix to find its canonical network, range and broadcast address. IPv4 addressPrefix length ## IPv6 Prefix Calculator Find the size of an IPv6 prefix. This calculator reports address count and prefix range; it does not enumerate individual IPv6 addresses. IPv6 address/prefix ## CIDR Subnet Reference Quick reference for common IPv4 prefixes. | CIDR | Subnet mask | Total addresses | Usable hosts* | *Conventional usable-host calculation; /31 and /32 have special handling. ## Understanding Subnetting Subnetting divides an IP network into smaller logical networks. CIDR notation (Classless Inter-Domain Routing) appends a prefix length to an address, such as **192.168.1.0/ 24**. The prefix indicates how many leading bits identify the network; the remaining bits identify addresses within that network. ### How to use this calculator Enter a parent network in CIDR notation and select an equal-size child prefix to list its subnets. Use the VLSM planner when segments need different sizes: specify each segment's host requirement and allocate the largest needs first. Reverse lookup identifies the network containing an IPv4 address. The IPv6 calculator reports prefix size without trying to list enormous address ranges. ### Important planning notes For most traditional IPv4 LAN subnets, the network and broadcast addresses are reserved, leaving total addresses minus two for hosts. Point-to-point /31 networks and /32 host routes are exceptions. Actual deployable capacity may also depend on gateway reservations, DHCP exclusions, network design, and vendor behavior. Always validate the plan against your equipment and requirements. ### Our Commitment At DBR Soft, our commitment is simple: **to help every business get the best out of its technology.** That starts with good planning, continues through careful deployment, and carries on with proactive management and support. We built this calculator to share some of that expertise. Use it to plan on your own, or bring your results to us and we’ll turn them into a complete, deployed solution. ### Who Is It For? **Business owners and office managers** planning a new office, a move, or an expansion **IT staff** who want a fast way to check their numbers **Teams adding Wi-Fi, VoIP, or security cameras** and wondering what their network can support **Anyone replacing aging equipment** who wants to size the new network properly ### Why Planning Matters Poor network planning is one of the most common causes of slow connections, dropped video calls, and costly rework. Taking time to plan up front helps you: **Avoid overspending** on equipment you don’t need **Avoid under-building** a network that can’t keep up **Prevent outages and slowdowns** before they happen **Make security easier** by separating traffic into properly designed segments **Grow without starting over** by leaving room for more users and devices ### From Calculation to Complete Solution A calculator gives you the numbers. DBR Soft gives you everything else. As both a **Managed Service Provider (MSP)** and a **Value-Added Reseller (VAR)**, we handle the whole project: **1. Network assessment and design:** Site surveys, Wi-Fi planning, and architecture tailored to your business **2. Equipment sourcing:** Firewalls, switches, access points, and cabling from leading vendors, at competitive prices **3. Professional deployment:** Installation, configuration, and testing, with minimal disruption to your operations **4. Security built in:** Firewalls, VLAN segmentation, secure remote access, and monitoring **5. Proactive monitoring and support:** We watch your network and fix issues before they affect your team **6. Documentation:** Clear network diagrams and IP plans, so nothing lives only in someone’s head ### Frequently Asked Questions **Is the calculator free?** Yes. Use it as often as you like. **Do I need technical knowledge to use it?** No. The tools use plain language and sensible defaults, and you can always ask us to review your results. **Are the results exact?** The calculator gives reliable planning estimates. Real- world conditions such as building materials, interference, and application behavior can vary, so we recommend a professional site survey before deployment. **Is my information stored?** Your inputs are used only to produce your results. See our privacy policy for details. **Can DBR Soft help me build the network I plan?** Absolutely. Send us your results and we’ll validate the plan, provide a quote, and handle the deployment. ### Plan It. Build It. Get the Best Out of It. Try the calculator now, then let our team help you put your plan into action. Contact DBR Soft for a free network planning consultation.