Which fitness calculator should you actually use?
I run one of these sites, so read this with that in mind. What the free calculator sites do better, what is different here, and the narrow case where mine is the right one.
Search any fitness number and the same handful of free sites come back. Most fund themselves through ads or something they would like you to buy, which is normal and worth knowing while you use one.
They are not bad. For a single number, one time, one of them is probably faster than making an account anywhere, mine included.
What the free calculator sites do better
Four things, none of them small.
Breadth I will never match
The big calculator libraries run to thousands of pages. I have 80. If your question is unusual, one of them almost certainly covers it and I almost certainly do not.
Years of being right
The established sites have been correct and online far longer than this one. That is why they rank, and it is a fair reason to trust them.
Instant, with nothing in the way
Load, type, get a number. No account, no interruption, nothing to decide first. That is a real feature and it is why people use them.
Deeper strength ranking exists elsewhere
Ranking a lift against a large pool of real submitted lifts is the stickiest thing in this category, and it is not what I do. My barbell bands are coarse on purpose and the one-rep max page says so.
Six things, each one checkable on the site
If any of these is not true when you use it, that is either a bug or a lie on this page. Tell me and I will fix whichever it is.
Your results are kept, and stay comparable
Almost every calculator saves its result, and they collect on one page with the history behind each. March reads against January. Saving without an account keeps it on that device; signing in, which is free, carries it everywhere.
Your inputs travel between calculators
Bodyweight, height, body fat, activity level, maintenance calories and resting heart rate live in one shared store. A calculator publishes what it learns and the next one prefills, so you type your weight once.
The result is translated, not just printed
Most calculators add a plain-language reading under the number: what it means for you, and two or three things to do next. It is written for a beginner, not for someone who already knows the formula.
The calculators are arranged into ordered flows
30 guided flows run a handful of calculators in a deliberate order, each step saying why it comes where it does. That is the difference between a shelf of tools and a route through them.
A plan drafted from your own numbers
Plans are built from the results you actually saved, labelled as your real logged numbers. Stale results drop out rather than being treated as current, and where you have saved nothing the plan is told nothing rather than handed a guess.
The number comes first, then the ask
No calculator here holds your result back for an email address. You get the full number, and only after it an invitation to save it. If that ever changes, hold me to this paragraph.
Pick by what you are actually trying to do
- You want one number, one time
- Use whatever ranks first. It will be faster than making an account anywhere, mine included.
- You want your lift ranked against other people
- A dedicated strength-ranking site will do that better than I can. Come back here for what to do with the answer.
- You want the research behind the formula
- The long-form nutrition and exercise-science sites write better context than I do. Every calculator here cites its own source if you want to start from mine.
- You are starting out and the numbers keep changing
- This is the case I built for. Run the calculators, let them keep your results, and read the numbers against each other as your bodyweight moves.
If the last one sounds like you
Start with the calculators. They are free, the result shows up before anything is asked of you, and your numbers carry from one to the next. You can decide later whether any of the rest of it is worth your time.