Enter CIDR, dash range, or start/end IPs and get total addresses, minimal CIDR blocks, and decimal values.
IP Range Calculator runs in the page as you use it. There is no input to submit and no result to fetch, because the whole thing happens on this side of the wire.
Everything runs client side, which is the only arrangement where a privacy claim is checkable. Open the network tab and watch it stay empty.
You will find it under Network, alongside 17 other tools for the same sort of job.
Detects if the range aligns to a single subnet.
10.0.0.0/24
Start IP: 10.0.0.0 End IP: 10.0.0.255 Total addresses: 256 Cidrs: 10.0.0.0/24 IP count: 256 Is subnet: yes Start IP decimal: 167772160 End IP decimal: 167772415
Yes. It is JavaScript running in this tab, so once the page has loaded it needs nothing further from the network. Put the machine in flight mode and it carries on. Nothing you do here is sent anywhere, because there is nowhere for it to go.
No. Reload the page and it starts from nothing. There is no account, no saved state and no cookie holding your last session. That is a deliberate trade: it cannot lose your data because it never keeps any.
Timing comes from performance.now(), the high resolution clock the browser provides, rather than from setInterval, which drifts by a few milliseconds every tick and compounds over minutes. What can still shift things is the browser throttling a tab in the background, so leave it visible if the timing matters.
Where a sound makes sense, it is generated with the Web Audio API rather than loaded as a file, so there is nothing to download and nothing to block. Browsers refuse to start audio until you have interacted with the page, which is why the first press is what switches it on.
Yes. The controls are sized for touch and the layout collapses to one column on a narrow screen. Bear in mind that a phone locking its screen will suspend the page, and timing stops with it.