📊 IP Range Calculator

🔢 What This Calculator Does

Enter a CIDR block, a Start–End pair, or a single IP against a range, and this tool computes the exact boundaries instantly — no manual bit math required. Switch tabs above depending on what you have: CIDR converts a block like 192.168.1.0/24 into its network/broadcast addresses; Start–End takes two IPs and returns the total count plus the tightest covering CIDR blocks; IP in Range Check tells you instantly whether a given address falls inside a CIDR block.

📋 Reading Your Results

After you calculate, the results panel shows several fields — here's what each means for your specific input:

• Network / Start address: the first address in your range — the anchor point everything else is calculated from.
• Broadcast / End address: the last address in your range.
• Total vs. Usable: Total is every address in the block; Usable subtracts the network and broadcast addresses (except for /31 and /32, see edge cases below).
• Binary & hex output: useful for cross-checking against router configs or packet captures that display addresses in non-decimal form.
• CSV export: for ranges under 4,096 addresses, download the full list; larger ranges show the first 256 with a full-count CSV still available.

⚠️ Edge Cases That Affect Your Result

/31 and /32 inputs: a /31 has no separate network or broadcast address — both of its 2 addresses are usable (point-to-point links, RFC 3021). A /32 is a single host route. This calculator flags both cases so the usable-count field doesn't mislead you.

Non-aligned input: enter an IP that isn't the network address for the given prefix (e.g. 192.168.1.5/24) and the tool still returns the correct /24 block by zeroing the host bits — your input IP will simply appear inside the range rather than at its start.

IPv6: this calculator is IPv4-only. For IPv6 range math, use the IPv6 Calculator.

🔧 Worked Example: How a /24 Is Calculated

The calculator does this instantly, but seeing the underlying math once makes every field on the results panel make sense. Take 192.168.1.0/24:

• Subnet mask: /24 means the first 24 bits are the network portion, leaving 8 bits for hosts — 255.255.255.0.
• Host bits available: 8 bits = 2⁸ = 256 total addresses.
• Network address: all host bits set to 0 → 192.168.1.0 (the anchor point; not assignable to a device).
• Broadcast address: all host bits set to 1 → 192.168.1.255 (also not assignable).
• Usable range: everything between them → 192.168.1.1 through 192.168.1.254 = 254 usable hosts (256 total minus the network and broadcast addresses).

A smaller block works the same way with fewer host bits: a /28 has 4 host bits (2⁴ = 16 total addresses, 14 usable), a /30 has 2 host bits (4 total, 2 usable) — which is why /30 is the traditional choice for point-to-point router links before RFC 3021 popularized /31 for the same purpose.

🛡️ Applying the Output

For the underlying CIDR theory, private/reserved ranges, and how ranges are used in firewalls, pentesting scope, and geolocation databases, see the full IP Range Calculator Guide.

🔗 More Ways to Work With IP Ranges

For full subnet splitting (VLSM), use our Subnet Calculator. For detailed CIDR mathematics including wildcard masks, try the CIDR Calculator. For geolocation and ASN data on any IP, use IP Lookup. Check ranges against blocklists with our Blacklist Checker. For understanding IP addresses deeper, read What Is an IP Address? and Public vs Private IP.