The numbers behind the coaching business, worked out with the formula in plain sight.
Each calculator ships the formula explained, a table of precomputed values and the assumptions it runs on, so you can check the result or do the arithmetic by hand. They are built for the coach who charges for the work, not for the person training.
6 calculators
The price you need to charge per session comes from dividing what you want to earn plus your fixed costs by the sessions you bill each month, adjusted for what tax and payment fees take. With a target of 2,000 a month, 300 in fixed costs, 60 sessions and 25% in deductions, the price is 51 per session. Fewer sessions raise the price in the same proportion.
Price per session = (Target income + Fixed costs) ÷ (Sessions per month × (1 − Deductions))
The number of clients you can handle comes from dividing your weekly hours of client work by what each client costs you per week, counting sessions and also programming, messages and check-ins. With 30 weekly hours, two one-hour sessions per client and two hours of admin, capacity is 7 clients. Admin hours weigh more than sessions do.
Capacity = Weekly hours ÷ ((Sessions per week × Duration) + Admin hours per client)
A client roster stops growing when arrivals match departures, so the ceiling is new clients per month divided by the monthly dropout rate. With 4 new clients a month and 10% dropping out, the roster settles at 40 clients, no matter how many you start with. At a fee of 80, that is 3,200 a month.
Steady roster = New clients per month ÷ Monthly dropout rate · Revenue = Roster × Monthly fee
A client's lifetime value is their monthly fee divided by the monthly dropout rate, because a 10% dropout rate equals an average stay of 10 months. At a fee of 80 and 10% dropout, each client is worth 800 across the relationship. Halving dropouts doubles that figure without touching the price.
Lifetime value = Monthly fee ÷ Monthly dropout rate · Average stay = 1 ÷ Dropout rate
Your estimated 1RM is the heaviest load you could lift once, calculated from a set you actually did instead of measured directly. With the Epley formula, 1RM = weight × (1 + reps / 30): 100 kg for 5 reps estimates 117 kg. It is an estimate, not a measurement, and it loses accuracy as reps climb. Under 10 reps it is dependable; past 12 treat it as a reference rather than a number.
Epley: 1RM = weight × (1 + reps / 30). Brzycki: 1RM = weight × 36 / (37 − reps). The two agree almost exactly at 10 reps and diverge from there: Epley returns the higher number on long sets, and Brzycki becomes unstable near 37 reps, where its divisor approaches zero.
RIR is the reps you have left in the tank when the set ends. Converting it to a percentage of 1RM needs both numbers: how many reps you did and how many you left. A set of 5 with 2 RIR means you could have done 7, and that lands around 81% of 1RM. The short rule: add reps and RIR together, then read that total off the percentage table. Each extra RIR drops the load by roughly 3 to 4 percentage points.
Equivalent reps = reps performed + RIR. That total is how many reps you could have done to failure, and it is what you read off the %1RM table. Using Epley inverted: %1RM = 1 / (1 + equivalent reps / 30). A set of 5 with 2 RIR is 7 equivalent reps, so 1 / (1 + 7/30) = 81%.
