Free fitness calculators that turn your numbers into a plan.
Pick a goal, enter a few numbers, and get a range you can act on. Then open the next tool. No account. Coaching is optional.
Popular tools
Five calculators. One next step.
Lose fat
Weight loss
Free weight loss calculator: estimate a week and date range to a goal weight using conservative weekly rates, not a promised deadline.
Anyone planning a fat-loss block who wants a week range, not a deadline.
12–18 weeks
Lose fat
Calories / maintenance
Maintenance calorie calculator and diet calculator: estimate TDEE with Mifflin-St Jeor, then compare 10–25% deficit scenarios. Default is 15%.
People who need a maintenance estimate and a 10–25% deficit range.
15% default
Build muscle
Protein
Get a daily protein range and a practical middle target, then split it across your meals.
Lifters who want a daily protein range they can actually eat.
g / day
Build muscle
Bulk / cut / recomp
Answer a few questions and get a path to consider, cut, lean gain, or recomp, with a clear next tool.
When you want both fat loss and muscle and need a path to try first.
Cut / lean gain / recomp
Get stronger
Strength / 1RM
Free strength calculator: estimate a one-rep max from a 1–10 rep set using three formulas. The headline number is the median.
Lifters estimating a max from a 1–10 set, not a tested attempt.
Median of 3
What ARC helps with
Product facts only. No invented reviews. Open a calculator, or see how the math works.
- Weight loss calculatorA week range for a fat-loss goal, not a promised deadline.
- Maintenance caloriesTDEE estimate, then deficit sizes as a planning range.
- ProteinA daily target from body weight and the goal you picked.
- Bulk / cut / recompWhether cut, lean gain, or recomp fits the numbers you have.
- Strength / 1RMA one-rep max from a submaximal set you already lifted.
- How ARC calculatesThe formulas, floors, and what the numbers are not.
Guides
Short explainers that sit next to the calculators. How to read a range, not a promise.
How ARC works
Each tool uses published formulas or conservative planning rates. You get a range, not a guarantee. The math stays on the page in Methodology. Use the number as a starting plan, then adjust from weekly data.
Questions
Are ARC fitness calculators free?
Yes. All five ARC fitness calculators are free to use: weight loss, maintenance calories and diet, protein, bulk vs cut vs recomp, and 1RM strength. Coaching is optional and separate.
What is a maintenance calorie calculator?
A maintenance calorie calculator estimates how many calories you need each day to hold your current weight (TDEE). ARC uses the Mifflin-St Jeor equation for BMR, multiplies by an activity factor, and shows a maintenance range. Open the calorie deficit and maintenance calculator, then pick a 10–25% diet deficit if your goal is fat loss.
How do I use a diet calculator?
Use a diet calculator to set daily calories and protein, not a rigid meal plan. Start with ARC’s maintenance estimate, choose a calorie deficit for fat loss or a small surplus to gain, then set protein with the protein calculator. Adjust from weekly weight, not from one day’s intake.
How does a weight loss calculator work?
ARC’s weight loss calculator projects a week and date range to a goal weight. Each week’s loss is 0.5%, 0.75%, or 1.0% of that week’s projected bodyweight, not the same number of pounds forever. The dates are planning estimates, not a promised deadline.
What is a strength calculator?
A strength calculator estimates how much you could lift for one clean rep (1RM) from a set you already did. ARC’s 1RM strength calculator runs Epley, Brzycki, and Lombardi on a 1–10 rep set and uses the median as the headline. It is a loading estimate, not a tested max.
How do I calculate TDEE or daily calories?
TDEE is maintenance calories: BMR times activity. ARC’s maintenance calorie calculator uses Mifflin-St Jeor, then activity multipliers from 1.2 to 1.9, and prints a range. If you already know the intake that holds your weight, enter that instead of the equation.
How accurate are fitness calculators?
They are planning estimates, not measurements. ARC uses published formulas or conservative weekly rates and shows a range. Use the number as a starting plan, then adjust from weekly data. How ARC calculates.
Can I use ARC for weight loss and muscle gain?
Yes. Start with the weight loss calculator or calorie deficit calculator for fat loss, and the bulk, cut, or recomp tool if you are choosing a path. Protein and the 1RM strength calculator sit next to those plans.
Do I need an account to use ARC?
No. You can run any calculator without signing in. There is no login and no saved cloud profile.
Does ARC save my information?
After you calculate, matching inputs are stored on this device so the next tool can prefill. Nothing is uploaded to an ARC account. You will see “Saved on this device” when that local write succeeded.
Optional coaching
The calculators do not require a coach. If you want weekly adjustments and accountability, that still exists.