Bühlmann Algorithm — What It Is and Why It Matters
The Bühlmann algorithm, formally known as ZHL-16C, is the most widely used decompression model in dive computers. Developed by Swiss physician Albert Bühlmann, it models the body as 16 tissue compartments with different half-times (from 4 to 635 minutes) that absorb and release inert gas at different rates. The algorithm calculates maximum allowable tissue tensions (M-values) to determine safe ascent profiles.
Bühlmann's model is popular because it is well-understood, extensively tested, and easily modified with gradient factors to adjust conservatism. Shearwater, Suunto, Heinrichs Weikamp, and many other manufacturers use Bühlmann ZHL-16C as their primary algorithm, often with proprietary modifications.
Learn More
Frequently Asked Questions
Is Bühlmann the best decompression algorithm?
It is the most widely used and extensively validated, but no single algorithm is definitively best. Bühlmann with gradient factors provides excellent flexibility. RGBM and VPM take different approaches to bubble modeling. The right choice depends on your diving style and preference for conservative vs. liberal profiles.
What does ZHL-16C stand for?
ZHL stands for Zürich Limits (referring to the University of Zurich where Bühlmann worked), 16 refers to the 16 tissue compartments in the model, and C is the revision letter. Earlier versions (A, B) had fewer compartments and different M-values.
Affiliate Disclosure: DiveComputers is a participant in the Amazon Services LLC Associates Program and eBay Partner Network. Links on this page may earn us a commission at no extra cost to you.