IPv4 CIDR & subnet calculator
Calculate the network, broadcast, masks, host range and address counts locally in your browser.
| Network | — |
|---|---|
| Broadcast | — |
| Netmask | — |
| Wildcard | — |
| First usable | — |
| Last usable | — |
| Total addresses | — |
| Usable hosts | — |
| Address scope | — |
What CIDR means
The number after the slash is the network prefix length. A /24 leaves 8 host bits, giving 256 total addresses. Traditional IPv4 subnets from /0 through /30 reserve the network and broadcast addresses; /31 and /32 are special cases where this calculator reports all addresses as usable endpoints. The tool accepts IPv4 prefixes from /0 to /32; it does not calculate IPv6 networks.
Worked examples: /24, /26, /31 and /32
For 192.168.1.10/24, the network is 192.168.1.0 and the broadcast address is 192.168.1.255. There are 256 addresses; the conventional host range is 192.168.1.1–192.168.1.254, or 254 hosts.
For 192.168.1.70/26, the first 26 bits identify the network: 192.168.1.64 through 192.168.1.127. That block contains 64 addresses, with the conventional usable range 192.168.1.65–192.168.1.126, or 62 hosts. A /26 is one quarter of a /24 address block.
| Example input | Network | Broadcast | Total addresses | Endpoint count reported |
|---|---|---|---|---|
192.168.1.10/24 | 192.168.1.0 | 192.168.1.255 | 256 | 254 |
192.168.1.70/26 | 192.168.1.64 | 192.168.1.127 | 64 | 62 |
192.168.1.4/31 | 192.168.1.4 | 192.168.1.5 | 2 | 2 |
192.168.1.5/32 | 192.168.1.5 | 192.168.1.5 | 1 | 1 |
Important distinction: a /31 is commonly used for a point-to-point link, where both addresses can be endpoints under RFC 3021. A /32 describes one individual IPv4 address. The calculator reports mathematical endpoint counts for these special prefixes; check your router or cloud provider's requirements before applying a live network change.
Privacy for network inputs
This is a mathematical subnet calculator, not an IP-location lookup. The entered address stays in your browser and no network request is needed.
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CIDR results describe address ranges, not network reachability
A CIDR calculation can identify the network range, mask and address boundaries for the entered prefix. It does not prove that a host exists, accepts traffic or is reachable through firewalls, routing rules, NAT or provider filtering.
Use the result when planning or checking IPv4 ranges, then verify the actual network configuration separately. Avoid assuming that every numerically valid address in a range is assignable in every environment.
Read a CIDR result in network context
The prefix length determines how many IPv4 bits belong to the network portion and how many remain for hosts. A /24 leaves eight host bits, while a /16 leaves sixteen. The calculated network and broadcast boundaries are mathematical properties of that block.
Cloud platforms, routers, VPNs and firewalls can impose additional rules. Some environments reserve addresses for infrastructure, and security policies can make an otherwise valid address unusable for a particular service.
Cross-check before a live network change
Verify the prefix, compare the calculated range with the current configuration, and confirm provider-specific reservations. CIDR arithmetic can identify a range; it cannot prove a host exists or accepts traffic.
Use the subnet result for planning, not reachability
CIDR combines an IPv4 address with a prefix length that identifies the network bits. Shorter prefixes cover larger ranges; longer prefixes cover fewer addresses. The calculator returns network, mask, broadcast and host-range values for planning.
Review the prefix and usable-host count
- Enter the IPv4 address and prefix length supplied by the network plan.
- Check that the prefix is between 0 and 32 and that the address is valid IPv4 syntax.
- Compare the calculated network and broadcast addresses against the intended allocation.
- Check special cases such as /31 point-to-point links and /32 single-host routes before applying a generic host-count assumption.
For example, a /24 network contains 256 total IPv4 addresses, but the conventional number available to ordinary hosts is often lower because network and broadcast addresses have special meanings. The treatment of small prefixes depends on the networking context and configuration. Do not copy a host count without checking the purpose of the subnet and the network equipment's rules.
Security and verification limits
This calculator performs address arithmetic; it does not scan a network, test host responses or grant access. A valid range can conflict with an existing plan, so verify allocations and routing with the network administrator before changing production systems.
CIDR questions
Does a calculated broadcast address prove that a host is online?
No. CIDR arithmetic describes an address range. Connectivity requires separate routing, firewall and service checks.
How to use IPv4 CIDR & subnet calculator for everyday work and study
IPv4 CIDR & subnet calculator is designed for freelancers estimating project hours, remote workers checking a quick business number, and students validating coursework before submitting it. For IPv4 CIDR & subnet calculator, the real benefit comes from applying the output correctly, not merely seeing a number or transformed value. For IPv4 CIDR & subnet calculator, enter source information carefully, then read the output in light of the assumptions that produced it. Use IPv4 CIDR & subnet calculator as a focused browser step when a quick check would otherwise mean setting up a separate spreadsheet.
Worked example: IPv4 CIDR & subnet calculator
Enter an IPv4 address and prefix, then verify the network address, mask, broadcast address, and usable-host range against a second calculation. Prefix edge cases, point-to-point networks, reserved ranges, and IPv6 rules require separate treatment. A valid subnet calculation does not prove that a network is reachable or secure.
Start with the inputs, not the answer
Before running IPv4 CIDR & subnet calculator, review the fields it actually uses, such as dates, units, text, quantities, or settings. A freelancer using IPv4 CIDR & subnet calculator can document a quote, invoice, proposal, delivery estimate, or other client-facing result with the inputs that produced it. For a remote team, IPv4 CIDR & subnet calculator can help inspect the input before it is translated into the team's agreed format or workflow. After completing the underlying work, students can use IPv4 CIDR & subnet calculator to check one specific part of the answer without replacing their own reasoning. For IPv4 CIDR & subnet calculator, an incorrect source value can still produce a misleading output, so review the original fields before relying on the result.
A practical US workflow
When a US freelancer uses IPv4 CIDR & subnet calculator, retaining the source value beside the output makes the check easier to explain later. For IPv4 CIDR & subnet calculator, note its relevant input, such as an amount, duration, text sample, unit, or setting, next to the output that the page returns. A remote teammate can document how IPv4 CIDR & subnet calculator was used in a project ticket, letting colleagues repeat the same steps. For coursework, IPv4 CIDR & subnet calculator works best alongside the original exercise: compare both to catch arithmetic, formatting, or conversion mistakes without skipping the learning step. Keeping the inputs with IPv4 CIDR & subnet calculator's output gives a client or teammate a trail to review instead of a number with no explanation.
When the result needs a second check
If IPv4 CIDR & subnet calculator is used for a contract, tax return, payroll choice, school requirement, or another consequential task, verify the result independently before relying on it. IPv4 CIDR & subnet calculator can speed up a routine calculation or transformation, but it cannot infer special project assumptions or know every change made by an outside authority. Before acting on IPv4 CIDR & subnet calculator's result, check its inputs, reproduce important figures independently, and ask the responsible organization about official requirements. IPv4 CIDR & subnet calculator is a practical utility, not a substitute for professional advice or an official record.
Tips for repeat use
- For IPv4 CIDR & subnet calculator, choose a unit and rounding convention and apply it consistently across the task.
- Save the inputs used by IPv4 CIDR & subnet calculator alongside its output whenever a client or teammate may ask how the result was reached.
- Only provide IPv4 CIDR & subnet calculator with information required for its task; leave out client secrets and unrelated confidential details.
- When sending a IPv4 CIDR & subnet calculator result to a client, label estimates clearly and state the assumptions that matter.
- For an assignment involving IPv4 CIDR & subnet calculator, follow the instructor's rules about permitted calculators, outside assistance, and submitted work.
Limitations and privacy
What IPv4 CIDR & subnet calculator returns depends on the information supplied and the method implemented on this page. IPv4 CIDR & subnet calculator may not cover every unusual input, local requirement, product-specific convention, or future change. If IPv4 CIDR & subnet calculator displays live or external data, check the stated source and timestamp instead of assuming the value stays current. For sensitive work, use the minimum information necessary. The best way to use IPv4 CIDR & subnet calculator is to understand the assumptions and verify consequential outputs rather than treating convenience as official authority.
Page-specific reference: IPv4 CIDR & subnet calculator. This guide explains practical cases for IPv4 CIDR & subnet calculator, including the points where its result needs independent confirmation.
Frequently asked questions about IPv4 CIDR & subnet calculator
What is IPv4 CIDR & subnet calculator used for?
IPv4 CIDR & subnet calculator helps complete the specific task represented by its fields and output. Use IPv4 CIDR & subnet calculator as a routine check, then confirm that its output matches the real-world task and assumptions you intended to evaluate.
Can freelancers use IPv4 CIDR & subnet calculator for client work?
A freelancer can use IPv4 CIDR & subnet calculator while preparing routine client work, but any quoted amount, converted asset, or consequential output should be checked against the client's assumptions before delivery.
Can students use IPv4 CIDR & subnet calculator?
A student can use IPv4 CIDR & subnet calculator to check a worked attempt when course rules permit outside tools. When using IPv4 CIDR & subnet calculator for coursework, students should show their own reasoning and comply with the instructor's submission requirements.
Is the result an official or professional determination?
No. The output from IPv4 CIDR & subnet calculator is informational, not an official determination. For consequential use of IPv4 CIDR & subnet calculator, confirm regulated decisions, formal requirements, and professional advice with the appropriate authority or qualified professional.
What should I do if the result looks wrong?
If IPv4 CIDR & subnet calculator produces an unexpected result, check its inputs, units, dates, and rounding settings. For an important IPv4 CIDR & subnet calculator result, reproduce the output independently and compare methods before relying on it.