Ideal Race Weight Calculator
Target racing weight from lean mass and a realistic timeline to reach it.
Enter your values
Enter the current weight in kg.
Enter the current body fat in %.
Enter the target race body fat in %.
Enter the weekly loss rate in % of bodyweight.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Target race weight
- 70 kg (154.3 lb)
- Weight to lose
- 5 kg
- Lean mass to protect
- 63 kg
- Weeks needed
- 13.3
- Loss per week
- 0.38 kg
- Daily calorie deficit
- 413 kcal
- Minimum healthy weight
- 66.3 kg at 5% body fat
Working
- 1lean = 75 x (1 - 16%) = 63 kg
- 263 / (1 - 10%) = 70 kg
Quick answer
Race weight is set by lean mass, not by a height chart. Hold lean mass constant, choose a realistic racing body fat, and the target weight follows.
race weight = lean mass / (1 - target body fat)
At a glance
| What it does | Target racing weight from lean mass and a realistic timeline to reach it. |
|---|---|
| Category | Fitness |
| Inputs needed | Current weight, Current body fat, Target race body fat, Weekly loss rate |
| Main output | Target race weight |
| Formula | race weight = lean mass / (1 - target body fat) |
| Cost | Free — no sign-up, no download |
How to use the Ideal Race Weight Calculator
- 1Enter your current weight and a body fat measurement you trust.
- 2Choose a racing body fat you have actually held before, not the lowest number you have read about.
- 3Use the weekly rate to time the cut so you arrive at race weight two weeks early, not on race morning.
Inputs explained
- Current weight(kg)
- Enter the current weight in kg.
- Current body fat(%)
- Enter the current body fat in %.
- Target race body fat(%)
- Enter the target race body fat in %.
- Weekly loss rate(% of bodyweight)
- Enter the weekly loss rate in % of bodyweight.
Worked example
Using the values the calculator loads with:
Inputs
- Current weight75 kg
- Current body fat16 %
- Target race body fat10 %
- Weekly loss rate0.5 % of bodyweight
Results
- Target race weight70 kg (154.3 lb)
- Weight to lose5 kg
- Lean mass to protect63 kg
- Weeks needed13.3
- Loss per week0.38 kg
- Daily calorie deficit413 kcal
- Minimum healthy weight66.3 kg at 5% body fat
- lean = 75 x (1 - 16%) = 63 kg
- 63 / (1 - 10%) = 70 kg
Frequently asked questions
How low should race body fat go?
Roughly 8 to 12% for male endurance athletes and 15 to 20% for female athletes. Going lower usually costs power, immunity and hormonal health.
Why lose only 0.5% of bodyweight per week?
Faster losses come substantially from lean mass and glycogen, which lowers power output — the opposite of what racing weight is for.
What do I need to enter into the Ideal Race Weight Calculator?
Just 4 values: current weight, current body fat, target race body fat, weekly loss rate. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Ideal Race Weight Calculator work out the answer?
Race weight is set by lean mass, not by a height chart. Hold lean mass constant, choose a realistic racing body fat, and the target weight follows. It applies the formula race weight = lean mass / (1 - target body fat) and shows the working so you can check each step by hand.
Is the Ideal Race Weight Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.