Finds the air depth with the same nitrogen partial pressure as a nitrox mix: the depth you take into the air tables.
The formula: EAD = N2% x (depth + 10)/79 - 10. Change any box and the full working updates. For study only, never for dive planning.
The IMCA ADS, BDS and LST papers ask this as a four-option question, with a calculator on screen. A free account gives you 15 practice questions for each exam, each with the worked answer and the document it comes from.