I Got Tired of Opening 5 Different Sites to Plan My Nutrition — So I Built One Free Hub

Source: Dev.to

I’m a web developer who also cares about fitness, and I’ve been frustrated by having to open multiple sites just to recalculate my nutrition plan. The typical workflow involved five different calculators—for TDEE, macros, calorie deficit, protein intake, and body‑fat percentage—many of which now require accounts, are riddled with ads, or have started pay‑walling basic features.

To eliminate that friction, I combined all of these tools into a single, free hub.

14 Free Health & Fitness Calculators

Anytools.io/health – everything in one spot, zero friction.

For Nutrition Planning

• TDEE Calculator – Uses the Mifflin‑St Jeor equation (the most accurate BMR formula according to the Academy of Nutrition and Dietetics). Enter your stats to get maintenance calories plus targets for weight loss and gain.
• Macro Calculator – Splits protein, carbs, and fat based on your goal (weight loss, maintenance, muscle gain) or custom ratios.
• Calorie Deficit Calculator – Set a target weight and see the daily deficit needed, plus a realistic timeline.
• Protein Intake Calculator – Calculates recommended protein ranges based on body weight and activity level, citing current sports‑nutrition research.

For Training

• Heart Rate Zone Calculator – Uses the Karvonen method (heart‑rate reserve) and displays all five training zones with target ranges.
• One‑Rep Max Calculator – Input weight and reps to get estimated 1RM using three formulas (Epley, Brzycki, Lombardi) for comparison.
• Pace Calculator – For runners: enter any two of distance, time, and pace to calculate the third, with race‑time projections for 5 km, 10 km, half‑marathon, and marathon.
• VO₂ Max Estimator – Estimates aerobic fitness based on running performance.

For Body Composition

• Body Fat Calculator – US Navy method using simple tape measurements (no calipers needed).
• Ideal Body Weight Calculator – Shows results from four formulas (Devine, Robinson, Miller, Hamwi) side‑by‑side.
• BMI Calculator – Provides the BMI value with context about its meaning and limitations.

Other Tools

• Water Intake Calculator – Based on body weight, activity level, and climate.
• Sleep Calculator – Calculates optimal bedtimes using 90‑minute sleep cycles.
• BAC Calculator – Estimates blood‑alcohol content.

Why I Built These as a Web Developer

• No download friction – A bookmarkable website works on any device instantly; no app installation required.
• Client‑side processing – All calculations run in the browser, so your personal data never leaves your device.
• No accounts – No sign‑ups, no data storage; just enter numbers, get results, and close the tab.
• No ads – The tools load quickly and cleanly without the overhead of ad scripts.

The Formulas Are Transparent

Many online calculators hide the equations they use, giving you a number with no context. Every calculator on Anytools displays the exact formula, cites the underlying research, and often lets you compare multiple methods side‑by‑side (e.g., TDEE uses Mifflin‑St Jeor; heart‑rate zones use Karvonen; 1RM shows Epley, Brzycki, and Lombardi). Whether you care about the math or just want an accurate result, the information is there.

What Else Is On the Site

The health calculators are part of a broader platform: Anytools.io

• 26 developer tools – JSON formatter, JWT decoder, regex tester, Base64 encoder/decoder, password generator, etc.
• 24 design tools – Color palette generator, CSS generators (flexbox, grid, glassmorphism), contrast checker, etc.
• 16 calculators – Compound interest, loan, mortgage, tip, unit converter, and more.

All follow the same principles: free, no accounts, client‑side, and no tracking.

If you regularly use any of these calculators, I’d love to know the one fitness or nutrition calculator you wish existed but doesn’t. I’m actively building new tools, and user requests are prioritized.