Gradient Factors Calculator

Gradient Factors — Key Features

• Calculate NDL for any depth with custom gradient factors
• 6 built-in GF presets from very conservative to aggressive, plus custom values
• Visualize how GF changes affect no-deco limits
• Based on the Bühlmann ZH-L16C algorithm with 16 compartments
• Support for air and nitrox gas mixes
• Educational tool for understanding decompression theory

Gradient Factors — How It Works

Select your gradient factor preset or enter custom GF Low/GF High values. Choose your gas mix (air or nitrox) and depth. The calculator instantly shows your no-decompression limit and ceiling depth based on the Bühlmann ZH-L16C algorithm.

Why Understand Gradient Factors?

• Make informed decisions about your dive computer's conservatism settings
• Understand why different GF settings lead to different NDL times
• Compare presets to find the right balance for your diving style
• Educational tool recommended by dive instructors

Gradient Factors — Frequently Asked Questions

What are gradient factors?

Gradient factors are two numbers (GF Low and GF High) that control how conservative your decompression algorithm is. GF Low affects the depth of the first deco stop, and GF High affects the no-decompression limit and surfacing criteria.

What GF settings should I use?

It depends on your experience, conditions, and risk tolerance. Common recreational settings are 40/80 (moderate conservative). More conservative divers use 30/70, while experienced technical divers may use 50/85. Start conservative and adjust based on experience.

Is this calculator free?

Yes! The gradient factors calculator is completely free to use. Create a free account to access this tool and explore all the other free calculators available on DiveToolbox.

How does GF Low affect my dive profile?

GF Low controls the depth of your first decompression stop. A lower value (e.g., 20) pushes your first stop deeper, which some research suggests helps reduce bubble formation. A higher value (e.g., 50) results in shallower first stops and shorter overall deco time.

Do gradient factors apply to no-decompression dives?

Yes. GF High directly affects your no-decompression limit (NDL). A GF High of 100 uses the full Bühlmann limit, while 80 reduces your NDL by roughly 20%, adding a built-in safety margin even for recreational dives within no-deco limits.

What is the Bühlmann ZH-L16C algorithm?

Bühlmann ZH-L16C is a dissolved-gas decompression model developed by Albert Bühlmann at the University of Zurich. It uses 16 tissue compartments with different half-times to predict nitrogen and helium absorption, and is the basis of most modern dive computers.