Work out pat port capacity instantly with clear inputs, formula shown and shareable results.
Carrier-grade NAT assigns each subscriber a fixed block of ports so logging stays deterministic. Capacity is then simply the total usable ports across the public pool divided by the block size: a 512-port block on 64,512 usable ports gives 126 subscribers per address. Larger blocks improve application compatibility but cut subscriber density proportionally.
PAT capacity
total ports = public IPs x usable ports; subscribers = floor(total ports / ports per subscriber)
Light browsing fits in a few hundred, but video, streaming and many devices per household push it higher. Providers commonly deploy 512 to 2048 ports per subscriber.
Web pages stall on some assets, and applications that open many parallel sockets fail intermittently, which is hard to diagnose from the client side.