Free Fitness Calculators and Your Daily Log - How They Connect
Use Refyuel's free TDEE, protein, macro, and 1RM calculators to set targets - then log against those numbers in Health OS for weekly progress.
In short
Free calculators give you starting numbers for calories, protein, and macros. A daily log in Refyuel Health OS shows whether you actually hit those targets alongside your training - that gap between plan and reality is where progress happens.
Calculators set the plan. Logging tells you whether the plan survived contact with a normal week.
Refyuel offers free tools on the web so you can set numbers before you download anything. Health OS is where those numbers meet your actual training and meals.
The calculator → log workflow
| Step | Tool or action |
|---|---|
| 1. Estimate maintenance calories | TDEE calculator |
| 2. Set protein target | Protein calculator |
| 3. Split carbs and fat | Macro calculator |
| 4. Reference lift numbers | 1RM calculator |
| 5. Log daily against targets | Refyuel Health OS |
Without step five, steps one through four are just math on a screen.
Why we publish free tools
Most fitness apps hide calculators behind sign-up walls. We publish them because:
- Trust: You can verify our numbers before trying the app
- SEO and education: Guides like how to calculate TDEE stand alone
- Continuity: Same brand, same logic from web tool to mobile log
The tools are starting points. Your 2-4 week trend in Health OS is the feedback loop.
Example - fat loss setup
1. TDEE estimate: 2,400 kcal maintenance 2. Target: 2,200 kcal (modest deficit) 3. Protein: 150 g/day from calculator 4. Log food in Health OS for 14 days 5. Review: average calories, protein, weight trend, gym performance
If weight is flat and lifts are fine, adjust by 100-150 kcal - not a new diet.
See calorie deficit without crash dieting.
Example - strength focus
1. Use 1RM estimates for programming reference only 2. Log working sets in Health OS each session 3. Track protein daily; calories at maintenance or slight surplus 4. Review rep and load trends every 2-4 weeks
See how to log workouts for progress.
All free Refyuel tools
Carry your numbers into the app
After you set targets, Refyuel Health OS keeps workouts and nutrition in one daily loop so weekly reviews take minutes, not spreadsheets.
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*Educational content only - not medical or dietetic advice. See our health disclaimer.*
Frequently asked questions
What is Refyuel?
Refyuel is a fitness software company. Our first product, Health OS, combines workout planning and logging with nutrition tracking in one mobile app for Android and iOS.
What is Refyuel Health OS?
Health OS is a fitness app and workout tracker that helps you plan training, log sets, track meals and macros, and review weekly gym progress - without switching between a workout app and a separate food diary.
When does the app launch publicly?
Public launch on App Store and Google Play is planned for June 2026. Beta testing is open now: join with your email to get early access before the wider release.
Is Health OS free during the beta?
Yes. The beta is completely free. You get full access to workout training and nutrition tracking at no cost.
How do I join the beta?
Submit your email on refyuel.com and pick your platform (Android or iOS). We will send you access details.
Is Refyuel a good fitness app for beginners?
Yes. Health OS keeps daily workout logging and calorie tracking straightforward for people new to the gym or building a habit.
Can I use only workouts or only nutrition?
Yes. Use the modules you need today and combine both when you want a full train-and-fuel daily loop.
Will my data carry over to the final release?
Yes - you are testing on our production system, so workouts, nutrition logs, and progress carry over to the public launch. You can delete your account anytime from Settings → Delete Account.
Join the Health OS beta
Get early access to workout tracking and nutrition logging on Android and iOS - free during the beta.