Why look at your numbers
One dive tells you very little. Fifty dives tell you a lot: how your diving has changed, where your comfort zone is, and what you might want to work on next. Statistics turn your logbook from a diary into a tool for planning.
None of this needs special equipment. It only needs the basics recorded consistently: depth, bottom time, water temperature, tank pressures and the place you dived.
Totals and how often you dive
Total dives and total bottom time are the figures dive centers ask about, and they are the prerequisites for many courses. Dives per year or per month show something just as important: how regularly you dive.
Regular diving keeps skills sharp. If your numbers show long gaps between trips, plan a refresher or an easy first dive at the start of each trip, and leave the most demanding sites for later in the week.
Depth: records, averages and progression
Your deepest dive is a fun record, but your average depth says more about your diving. A depth distribution shows how much of your diving happens in each range, and a progression chart shows whether you have been going deeper over time.
Going deeper is not a goal in itself. If your progression climbs, check that your training, your gas planning and your experience have kept up, for example with a deep specialty or nitrox, which is most useful between about 18 and 30 meters.
Gas consumption and SAC rate
Your surface air consumption, or SAC rate, is how much gas you would breathe per minute at the surface. It lets you compare dives at different depths, because consumption rises with depth as the gas you breathe gets denser.
To work it out, take the pressure you used, multiply it by the tank volume to get liters, then divide by the bottom time and by the average absolute pressure, which is roughly depth in meters divided by ten, plus one. For example, using 150 bar from a 12 liter tank in 45 minutes at an average of 15 meters is 1,800 liters ÷ 45 ÷ 2.5, or 16 liters per minute.
A lower SAC rate means longer dives on the same tank. Calm breathing, good trim and buoyancy, the right weighting and staying warm all bring it down, and it usually improves with experience. Knowing yours makes gas planning much more realistic than guessing.
Places, buddies, gear and training
Countries and sites visited, your most dived country and your favorite buddies are the fun side of statistics, and they make good memories. They also have practical uses: gear usage shows which pieces are getting the most dives and may need service sooner, and a certification timeline shows how your training has kept pace with your diving.
How Frey Dive helps
Frey Dive calculates all of this from the dives you log: totals, records such as your deepest and longest dives and your coldest and warmest water, averages, dives by country and over time, depth distribution, and your average and best SAC rate when you record tank pressures. Premium adds advanced statistics on depth progression, buddies, gear usage and training.
The more completely you log, the more these numbers tell you, and the better your next plan will be.