A 6-week study plan for the divemaster theory exam
In short
This divemaster theory exam study plan takes six weeks at 20 to 30 minutes a day: gas laws and gas use, partial pressures and buoyancy, physiology, decompression theory and equipment, skills and environment, then mixed review with practice exams. Each day: one lesson, a quiz from memory, your spaced reviews and two calculations by hand.
It’s 9 p.m. after a day of workshops, and Boyle’s law made sense in class. You work out the absolute pressure at 25 m (82 ft), get 2.5 bar, and the answer is 3.5. This plan fits those evenings: 20 to 30 minutes a day, one block of topics a week, and a list of the classic calculation traps so you can spot them early.
What does the divemaster theory exam cover?
It covers the science of diving. PADI’s blog lists the Divemaster course’s knowledge development as dive physics, physiology, equipment, dive skills and environment, decompression theory, and the agency’s standards and procedures, with several knowledge reviews and two exams: Dive Theory and Standards. SSI, NAUI and other agencies run similar but not identical programs: check your course outline with your instructor.
Octo is unofficial and not affiliated with PADI. Its 16 Divemaster lessons cover physics, physiology, equipment and leading divers; skills and environment come from its other three levels. It doesn’t cover the standards exam. Overview: Divemaster theory.
How is the 6-week plan organized?
Each week takes one block, in the order the topics build on each other. Lesson names from Octo are shortened.
| Week | Focus | Lessons in Octo |
|---|---|---|
| 1 | Pressure, volume and gas use | Divemaster: Boyle’s law, Charles’s law · Open Water: Pressure and volume, Air consumption |
| 2 | Partial pressures, nitrox, buoyancy | Divemaster: Dalton’s law, Archimedes · Advanced: Enriched air nitrox |
| 3 | Physiology | Divemaster: Henry’s law, Breathing and carbon dioxide, Toxic and narcotic gases · Open Water: Equalizing, Never hold your breath, Decompression sickness · Rescue: First aid for diving injuries |
| 4 | Decompression theory, equipment | Divemaster: Decompression theory, Regulators, cylinders and computers · Open Water: Dive computers · Advanced: Overstaying your no-decompression limit |
| 5 | Skills, environment, leading divers | Advanced: Compass, Natural navigation, Buoyancy and trim, Drift and boat diving · Open Water: The dive environment · Divemaster: Leading divers module, two lessons a day |
| 6 | Mixed review, practice exams | Divemaster practice exam, then your weakest module |
Try a question from the app
half-time arithmetic
A 20-minute compartment starts in balance with the surface. After 40 minutes at a constant depth, how close is it to saturation?
Show the answer
Answer B. Two half-times: 50% after the first, then half of the remaining 50%, so 75%. 100% assumes a steady, linear fill; 87.5% takes three half-times.
What does a study day look like?
A study day takes 20 to 30 minutes and follows the same five steps.
- Learn one new lesson: 4 to 6 minutes in Octo, or the matching chapter of your course materials.
- Answer its six questions from memory, before rereading anything.
- Clear today’s review. A missed question comes back the same day, then at longer and longer intervals.
- Work two calculations by hand from the formulas cheat sheet, in your course’s units.
- Explain one idea out loud: why a MOD is rounded down, why fast compartments limit deep dives.
Which calculations do you need to master?
Eight kinds of calculation come up again and again, and most mistakes come from a few traps. Octo builds its wrong answers from these errors, and each explanation names the one behind every wrong choice.
| Calculation | Common trap |
|---|---|
| Absolute pressure and Boyle’s law | Gauge pressure: 2.5 bar instead of 3.5 bar at 25 m (2 atm instead of 3 ata at 66 ft) |
| Gas use and SAC | Forgetting density: 18 L/min at the surface is 72 L/min at 30 m (0.6 cu ft/min is 2.4 at 99 ft) |
| Charles’s law | Degrees Celsius or Fahrenheit instead of kelvin or Rankine |
| Partial pressure and MOD | Forgetting to subtract the atmosphere, or rounding the MOD up |
| Best nitrox mix | Percentages (32) instead of fractions (0.32) |
| Apparent weight and lift | Freshwater density in the sea, or adding instead of subtracting |
| Half-times | A straight-line fill: two half-times give 75%, not 100% |
| Kick-cycle distance | Assuming 1 m (3 ft) per kick instead of calibrating |
Try a question from the app
measuring surface consumption
After a dive at an average depth of 20 m, a guest’s log shows he used 125 bar from a 12 L cylinder in 25 minutes. What is his surface consumption?
Show the answer
Answer B. 125 bar × 12 L = 1500 L in 25 minutes: 60 L/min at 3 bar, so 60 ÷ 3 = 20 L/min at the surface. 60 L/min is his rate at depth; 30 L/min divides by the gauge pressure.
Why mix topics in the last weeks?
Mixing topics forces you to pick the right formula, as an exam does. A review of ten study techniques rated practice testing and spaced study as the most useful, and interleaved practice, mixing problem types, as moderately useful (Dunlosky and colleagues, 2013). Spacing has a timing rule too: when the final test came a week after a review, the best gap before that review was about 20 to 40% of the week (Cepeda and colleagues, 2008). From week 3, add a few questions from earlier weeks every day.
How should you use practice exams?
Use them to find your weak spots and to practice against the clock.
- End of week 1: take Octo’s Divemaster practice exam once: 30 questions, including real-life scenarios, scored at the end.
- Note the module to review first and give it extra time.
- Week 6: take it every other day with the timer on and compare your attempts.
- For every miss, rework the calculation by hand and name the trap. Your real exam asks different questions.
What if you only have two weeks?
Keep the same order and the daily review, and double the pace.
| Days | Focus |
|---|---|
| 1–3 | Pressure, Boyle, Charles, gas use |
| 4–5 | Dalton, MOD, best mix, buoyancy |
| 6–7 | Physiology and Henry’s law |
| 8–9 | Decompression theory and equipment |
| 10–11 | Skills, environment, leading divers |
| 12–14 | Mixed calculations and practice exams |
Frequently asked questions
How long should you study for the divemaster theory exam?
Plan about six weeks at 20 to 30 minutes a day if your theory is rusty, two intensive weeks if it’s fresh. PADI says the whole Divemaster course takes from two weeks to six months: agree on timing with your instructor.
Is the divemaster theory exam hard?
It’s demanding mostly because of its breadth. The calculations use simple arithmetic; most mistakes come from gauge versus absolute pressure, temperature scales and rounding. Daily quizzes from memory and mixed practice are the best training. More in how hard is divemaster theory.
Do you need dive tables for divemaster theory?
If your course uses a dive table, learn it with your instructor and your course materials. Octo contains no tables: it teaches decompression theory through compartments, half-times, M-values, gradient factors and your dive computer.
Should you learn the formulas in metric or imperial?
Learn them in the system your course uses, and never mix the two in one problem: 10 m per bar and 33 ft per atmosphere are separate rounded conventions. Octo lets you choose meters and bar, or feet and psi. See metric vs imperial dive math.
