Numbers you can act on, not numbers you have to guess at.
ToolsToHealth turns nutrition and fitness research into simple calculators — enter a few details and get a clear, sourced answer in seconds. No account, no email wall, no ads getting in the way.
Calculators
A few of the tools people use most. The full library covers nutrition, growth, dosing, and clinical scores, and it keeps growing.
Protein Intake Calculator
Get a personalized daily protein range based on your weight, activity level, and goal — updates instantly as you type.
Open calculator Weight management · LiveCalorie Needs (TDEE) Calculator
Estimate your daily calorie needs for maintenance, gradual loss, or gradual gain.
Open calculator Vitals · LiveBody Fat Percentage Estimator
A U.S. Navy circumference-method estimate of body fat percentage from a few tape measurements.
Open calculatorFind tools by what you’re trying to do
Most people land here with a goal, not a calculator name in mind. As the library grows, this is where you’ll find the right tool for each one.
Stay generally healthy
Baseline nutrition and activity numbers for people who just want to eat and move well.
Build muscle
Protein, calorie surplus, and training-load numbers for people working on size and strength.
Lose fat, keep muscle
Calorie targets and intake ranges built around preserving lean mass during a deficit.
Train and compete
Fueling and recovery numbers for runners, cyclists, and other endurance athletes.
How we build a calculator
Every tool goes through the same four steps before it’s published — the goal is a number you can trust, explained plainly enough to actually use.
Start from the research
We pull ranges from bodies like the National Academies, the ISSN, and peer-reviewed studies — not blog-post averages.
Show a range, not a lie
Real biology varies by person. Every result is a range with a practical midpoint, never a single falsely precise digit.
Test the edges
We check empty fields, unit switches, and extreme inputs so the tool never shows a broken or misleading number.
Say what it isn’t
Every calculator is clearly labeled as an estimate for generally healthy adults — not a diagnosis or medical advice.
Guides & articles
Plain-language explainers that sit alongside the calculators — for when you want the “why,” not just the number.
How much protein do you actually need?
What the research says about protein needs by activity level, goal, and age — the reasoning behind our calculator’s ranges.
Read the guide Weight management · LiveUnderstanding TDEE and calorie needs
What “maintenance calories” actually means, and why two people the same size can need very different amounts.
Read the guide Vitals · LiveBody fat percentage, explained
How estimation methods work, how accurate they really are, and what the number can and can’t tell you.
Read the guideFrequently asked questions
The questions we hear most about the site itself, not any one calculator.
Are these calculators free to use?
Yes, every calculator on ToolsToHealth is free, with no usage limits and no premium tier.
Do I need to create an account?
No. Every tool works the moment you land on the page — there’s nothing to sign up for and no email required.
Do you store the information I enter?
No. Calculations run entirely in your browser as you type; nothing you enter is sent to or saved on our servers.
Are the calculators medically reviewed?
Each calculator is built from published research from sources like the National Academies and sports-nutrition and medical organizations, and we link to those sources on every calculator page. They’re not a substitute for personalized advice from a doctor or registered dietitian.
Can I suggest a calculator you haven’t built yet?
Yes — email us at hello@toolstohealth.com with what you’re trying to figure out, and we’ll consider it for the next tool we build.