NDL Calculator — No-Decompression Limits
Quick lookup of recreational no-decompression limits by depth, based on PADI RDP Table 1. Metric and imperial units.
At 18 m max depth, the PADI RDP Table 1 limit before required decompression stops.
How to use: This is the absolute no-deco limit, not a target. Add safety margin (most divers exit with 5 min NDL remaining). Always defer to your dive computer in-water. Repetitive dives need pressure group tracking — use a computer or the full RDP wheel.
Disclaimer: This tool is an educational aid. It is not a substitute for a personal dive computer, proper certification, or current medical advice. Plan dives conservatively and consult a dive professional when in doubt. Emergency: DAN Asia-Pacific +61-8-8212-9242.
Frequently asked questions
Why does this match my dive computer most of the time but not always?
Dive computers use real-time depth integration (you spend time at varying depths, not flat profiles), and most computers use the Bühlmann ZH-L16 algorithm with personal gradient factors. The PADI RDP is more conservative for square profiles but doesn't credit slower ascents the way Bühlmann does.
Is the PADI RDP still current?
Yes — the metric Table 1 values have not changed since the 1988 release. PADI still teaches and certifies on the RDP for recreational divers. The eRDPml is a digital version of the same tables.
What about altitude diving?
This calculator assumes sea-level. Altitude diving requires adjusted tables (or a computer with altitude mode). Above 300m elevation, theoretical ceiling depths shift down.
Can I use this for repetitive dives?
Not directly — pressure-group tracking is required for repetitive diving. Use your dive computer, or the full PADI RDP wheel/eRDPml app. We may add a multi-dive calculator in a later release.