Deco Dive Planner

Buhlmann ZHL-16C with gradient factor visualization

Warning: This planner is for educational purposes only. It is not a substitute for proper decompression software, dive tables, or formal technical diving training. Never plan real dives with this tool alone. Always use validated planning software (MultiDeco, Shearwater Desktop, Subsurface) and carry redundant computers.

Dive Parameters

Profile

Bottom Gas

44

Deco Gases (optional)

Gas Analysis at Depth

PPO2 at depth--
MOD (1.4)--
END--
MOD (1.6)--
Gas Density--
Min Depth--

Gradient Factors

GF Low applies at the deepest stop; GF High at the surface. Lower = more conservative = more deco but greater safety margin.

30%
10% Conservative100% Aggressive
85%
10% Conservative100% Aggressive

Common Presets

Conservatism Level

Moderate-Conservative

A balanced approach. Adds meaningful safety margin without excessive deco.

Understanding Gradient Factors

The Buhlmann ZHL-16C algorithm models your body as 16 theoretical tissue compartments, each absorbing and releasing inert gas at different rates. The fastest compartment (4-minute half-time) saturates quickly. Think blood. The slowest (635-minute half-time) represents tendons and fat.

Each compartment has an M-value, the maximum inert gas pressure it can theoretically tolerate at a given ambient pressure. Gradient Factors add conservatism by only using a percentage of the available gradient between ambient pressure and the M-value.

  • GF Low controls how close to the M-value you get at your deepest stop. Lower = deeper first stop.
  • GF High controls how close to the M-value you are at the surface. Lower = more shallow stop time.

GF Examples

100/100No conservatism. Surfacing right at the M-value. Not recommended.
30/85Moderate conservatism. Popular among experienced tech divers.
20/70Aggressive conservatism. Significant deep stops. Cold water or cautious divers.