Diving Decompression Stop Calculator
This tool helps recreational divers understand safety stop requirements and no-decompression limits (NDL) based on US Navy dive table values. Enter your planned dive depth to see the NDL and the recommended safety stop. This tool is for educational reference only. Always use a validated dive computer or certified dive tables for actual dive planning.
Warning: This tool shows recreational reference values only. Never use this for technical diving or as a substitute for a certified dive computer.
US Navy dive table NDL reference (recreational depths)
| Depth (m) | Depth (ft) | NDL (minutes) |
|---|---|---|
| 10 | 33 | 219 |
| 12 | 40 | 147 |
| 15 | 50 | 80 |
| 18 | 60 | 56 |
| 21 | 70 | 37 |
| 24 | 80 | 25 |
| 27 | 90 | 20 |
| 30 | 100 | 15 |
| 40 | 130 | 10 |
NDL values from US Navy Diving Manual, Revision 7 (2016). Recreational dive agencies (PADI, NAUI, SSI) use conservative versions of these values. Always defer to your dive computer's real-time calculations.
Diving decompression stop calculator: frequently asked questions
What is a decompression stop in scuba diving?
A decompression stop is a pause at a fixed depth during a diver's ascent to allow dissolved nitrogen (or helium in technical mixes) to safely leave the body. During a dive, the body absorbs inert gas under pressure. Ascending too quickly can cause decompression sickness (DCS) if gas comes out of solution as bubbles in the tissues. Decompression stops allow controlled off-gassing.
What is the standard recreational diving safety stop?
PADI, SSI, and NAUI all recommend a precautionary safety stop of 3 minutes at 5 metres (15 feet) at the end of every recreational dive. This is especially recommended for dives deeper than 18 metres (60 feet). The safety stop is not a mandatory decompression stop but provides an additional nitrogen off-gassing margin.
When does a dive require a mandatory decompression stop?
A mandatory decompression stop is required when a diver exceeds the no-decompression limit (NDL) for their depth and dive time, as defined by dive tables (US Navy tables) or their dive computer's algorithm. Once mandatory decompression is incurred, the diver cannot ascend directly to the surface and must stop at specified depths for specified times before surfacing.
What is the no-decompression limit (NDL)?
The NDL is the maximum time a diver can spend at a given depth on a single dive without incurring mandatory decompression stops. For example, the US Navy Dive Tables show an NDL of about 60 minutes at 18 metres (60 feet) and 20 minutes at 30 metres (100 feet) for a single dive. Dive computers track real-time nitrogen loading and display a remaining NDL.
Is this calculator a substitute for dive tables or a dive computer?
No. This tool is for educational reference only, explaining the concept of decompression stops and the recreational safety stop standard. For actual dive planning, always use validated dive tables (US Navy, NAUI, or PADI) or a certified dive computer. Never rely on an online calculator for dive decompression planning.
Official sources
- US Navy Diving Manual, Revision 7 (2016): Official US Navy dive tables and decompression procedures.
- Divers Alert Network (DAN): Decompression illness information and safety.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.