CIDR / Subnet Visualizer
See an IPv4 subnet drawn as a grid of addresses — the network, the broadcast, and every usable host in between. It all renders live in your browser.
/22 and longer (up to 1,024 addresses). Bigger blocks show a summary.
What this tool does
Subnets are usually described in numbers — a network address, a broadcast address, a host count — but numbers can hide the shape of a block. This visualizer draws every address in a subnet as a small cell so you can see how big the block is and where the special addresses sit. The first cell is always the network address, the last is the broadcast address, and the cells between them are the usable hosts you can hand out to devices.
Because address space grows by powers of two, a grid only makes sense for small blocks. A /26 has 64 addresses and fits comfortably on screen; a /24 has 256; but a /16 has 65,536 and a /8 more than sixteen million. Drawing a cell for each of those would freeze any browser, so this tool renders the grid only for prefixes /22 and longer and shows a compact numeric summary for anything larger.
Hover a cell to read its exact address. The pattern you see is the same one your router uses: the network and broadcast addresses are reserved bookends, and everything inside is fair game for hosts — except on a /31 or /32, where there is no separate broadcast and every address counts.
If the relationship between the prefix length and the number of cells still feels mysterious, our guide to what a subnet mask is explains how each bit of the mask halves or doubles the block, and what an IP address is covers the underlying 32-bit structure.
Everything is computed and drawn locally, so nothing you type leaves your device. Want the raw numbers instead of a picture? The IPv4 Subnet Calculator lists every field, and the CIDR → IP Range tool shows the first and last address of any block.
Frequently asked questions
Why can't I visualize a /8 or /16 as a grid?
A /16 holds 65,536 addresses and a /8 holds over 16 million — far too many to draw as individual cells without freezing your browser. This visualizer draws a cell per address only for prefixes /22 and longer (up to 1,024 addresses). For larger blocks it shows a numeric summary of the network, broadcast, and host range instead.
What do the colours in the grid mean?
The first cell is the network address (the identifier for the block), the last cell is the broadcast address (used to reach every host at once), and every cell in between is a usable host address you can assign to a device. A /31 and /32 are special cases with no separate broadcast, so all their addresses are treated as usable.
How many usable hosts are in a /24?
A /24 contains 256 total addresses. Subtracting the network and broadcast addresses leaves 254 usable host addresses. The visualizer shows this by colouring the first and last cells differently from the 254 host cells between them.
Does this tool send my subnet anywhere?
No. The grid is drawn entirely in your browser with JavaScript. Nothing you enter is uploaded, logged, or shared, so it is safe to visualize internal subnets offline.
Want the theory? Read the guides → · Visit the zoo →