Subnet Calculator
Free IPv4 subnet calculator that turns any IP address and CIDR or netmask into a stylised, exact-scale printable report — network and broadcast addresses, usable host range, wildcard mask, address class and type, a binary breakdown and a range visualisation.
Type an IP address (for example 192.168.1.10) and a mask — either as a CIDR prefix like /24 or a dotted-decimal mask like 255.255.255.0 — and the calculator instantly works out the whole subnet: the network address, the broadcast address, the first and last usable host, the total and usable host counts, the wildcard mask used in ACLs, the block size and interesting octet, and whether the address is private, public, loopback, link-local or multicast.
The printable report lays it all out with panels, tables and a colour-coded address-range bar. The binary breakdown shades the network bits so you can see exactly where the prefix boundary falls across the four octets. It prints at exact scale in real millimetres on A4, Letter or any size — handy for network admins, documenting an IP plan, or anyone studying for a networking cert.
Printing at exact scale
Every sheet is drawn in real millimetres and prints at exact physical scale. For accurate output, set Scale = 100% (Actual size) and Margins = None in your browser's print dialog. Not sure your printer is honest? Run the printer ruler test first to confirm 50 mm really measures 50 mm. Prefer a file? Use the PDF, PNG or SVG buttons to download the sheet instead of printing — PDF and SVG keep the exact dimensions, and PNG is a 300 DPI image.
Frequently asked questions
What does the subnet calculator work out?
From an IP + mask it computes the network and broadcast addresses, the first and last usable host, total and usable host counts, the subnet and wildcard masks, the CIDR prefix, address class, address type (private/public/loopback/link-local/multicast), block size and a full binary breakdown.
Can I enter a dotted netmask instead of CIDR?
Yes — the netmask field accepts either a CIDR prefix (“24” or “/24”) or a dotted-decimal mask (“255.255.255.0”). Both produce the same result.
Does it handle /31 and /32?
Yes. A /32 is treated as a single host route and a /31 as an RFC 3021 point-to-point link (two usable addresses, no network/broadcast subtraction).
Is it really free?
Yes. Every template on printsheet.io is completely free, with no sign-up, no account and no watermark. Generate as many sheets as you like.
How do I get an exact-scale print?
Choose your paper size, then in the print dialog set Scale to 100% or “Actual size” and Margins to None. The sheet is defined in real millimetres, so it prints at true size. Use the calibration ruler page to verify.
Which paper sizes are supported?
A4, A5, A3, A6, US Letter, Legal and Tabloid, in portrait or landscape. Pick the size that matches the paper loaded in your printer.
Can I save it as a PDF instead of printing?
Yes — choose “Save as PDF” as the printer in your browser's print dialog. The PDF keeps the exact millimetre dimensions.
Can I download it as an image (PNG or SVG)?
Yes — as well as Print and PDF, every sheet has a PNG and an SVG download button. PNG gives you a high-resolution (300 DPI) image at the exact page size, ideal for pasting into a document or sharing. SVG is a scalable vector file that stays razor-sharp at any size and can be edited in tools like Inkscape or Illustrator. Both are generated in your browser from the sheet you see on screen.