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 Health OS?
Health OS is Refyuel’s mobile fitness app for iOS and Android. It combines workout planning and set logging with meal and macro tracking, lifestyle Habits, and progress review (history, PRs, trends).
What features are in Health OS?
Workouts (templates, set logging, rest timers, Warmup/Main/Cooldown), nutrition (food search, meals, calories and macros), Habits (daily check-ins, streaks, guided programs), and progress (session history, personal records, weight trends, workout frequency), plus For You tips and wins.
Where is Health OS available on the App Store?
Health OS is on the App Store in Australia, Canada, India, New Zealand, the UAE, the United Kingdom, and the United States. We plan to expand to more countries soon. Open the App Store listing.
Is Health OS free?
Yes. Core workout, nutrition, and Habits logging are free at launch. Advanced features may be added later as optional upgrades.
How do I get started?
On the web, answer a few questions, create your account, and get a matched plan via Get started. Then open the Health OS app to train, log nutrition, and use Habits.
Do I log workouts on the website?
No. The website is for setup and creating your account. Daily workouts, nutrition, and Habits happen in the Health OS app.
Can I use only workouts or only nutrition?
Yes. Use workouts, nutrition, or Habits on their own, or combine them for a full train-and-fuel day.
Where do I download the app?
Health OS is on the App Store in Australia, Canada, India, New Zealand, the UAE, the United Kingdom, and the United States — expanding soon — and on Google Play. Create your account first via Get started, then open the app.
How do I delete my account?
Delete from Profile → Settings in the app, or follow the steps on our delete account page. Confirmed deletions are purged within 30 days.
Get started with Health OS
On the web: answer a few questions and create your account. Workouts and nutrition live in the Health OS app on Android or iOS.
Get startedOr download: Google Play · App Store