Choose a task
Each calculator here answers one question, so the quickest way to choose is to start from what you want to know. If you want an estimate of the energy your body uses at rest, open the BMR calculator. If you already have a daily calorie figure and want it as grams of protein, carbohydrate and fat, use the macro calculator. If you want to compare published protein amounts for your body weight, use the protein calculator. If you have a distance and a time and want a pace, a set of splits or a projected finish, use the pace calculator. The tools use the same layout and the same explicit Calculate button, and results disappear when you change an input so an old answer is never left beside new numbers.
Resting energy, daily intake and pace
Three different quantities are easy to confuse. Resting energy is what the body uses with no activity at all, which the BMR tool estimates with three published equations. Daily energy is higher, because movement and digestion add to it, and the tools show it only as illustrative activity scenarios, never as a measured figure. Intake is what you actually eat, which none of these calculators know. The macro and protein tools can take a daily energy number you type in, or one built from the BMR equations and an activity factor, and then turn it into grams. Pace belongs to a separate task. It is about distance and time, not food, and it is a plain division with no estimate of fitness behind it. Keeping these ideas apart makes each result easier to read and to question. The BMR page shows all three equations side by side so you can see the gap between them, and the macro and protein pages let you type the energy figure yourself if you already have one from a plan or a professional.
Unit conventions
The calculators accept both metric and everyday units, and the conversions are exact. One inch is 2.54 centimeters, one pound is 0.45359237 kilograms, one mile is 1,609.344 meters and one yard is 0.9144 meters. Energy is shown in kilocalories, and the BMR page also shows kilojoules at 4.184 kilojoules per kilocalorie. Protein and carbohydrate are counted at 4 kilocalories per gram and fat at 9. Switching between metric and US units keeps the underlying measurement, so toggling does not slowly change your numbers through rounding. Times are entered in separate hour, minute and second boxes, because 5.30 is not 5 minutes and 30 seconds. Distances are limited to the equivalent of 1,000 km, and body measurements to ranges the formulas were built for, so an obvious typing slip is caught instead of producing a wild number.
How estimates and formulas differ
A formula is not a measurement. The three BMR equations were fitted to different groups of people and they disagree with each other by design. The protein page shows three references side by side, a general adult allowance, a published range for people who exercise and a figure you choose, and does not merge them into one best number. The macro page compares your split with adult reference ranges and flags a split outside them without judging it. Sources behind the pages were read on 7 November 2026 and are reviewed at least once a year. The numbers are for healthy adults aged 19 and over and are not for pregnancy, breastfeeding, children or any condition where a clinician sets nutrition. Where a page uses a published range, it says which source the range comes from and what the range is for. It is meant to inform a question, not to answer it for you.
Privacy and using results
Every calculation runs in your browser. Your age, height, weight, calories, distances and times are not sent to a server, are not put in the page address and are not kept in your browser's storage. The site records only that a calculator was used and which of a fixed list of modes was run, never the values you typed. A downloaded CSV contains numbers and fixed labels only. Use the results to ask better questions, not to make a medical decision, and talk to a doctor or registered dietitian about anything that affects your health. Nothing needs an account, a login or an email address to use. The optional newsletter box at the bottom of each page is separate from the calculators and is never used to store what you calculate.
Fitness and health calculator questions
Which calculator estimates resting energy?
The BMR calculator. It compares three published equations in kilocalories and kilojoules and shows illustrative activity scenarios from the one you select. It also shows each result in kilojoules for readers who prefer them.
Which one converts calories into grams?
The macro calculator. Give it a calorie figure and a split between carbohydrate, protein and fat, and it returns daily grams and an equal per-meal breakdown. The calorie figure can be typed in or estimated from the BMR equations.
Which one compares protein references?
The protein calculator. It lists a general adult reference, a published range for exercising adults and your own factor, each in grams a day for your weight. It never merges them into one best number, and it explains where each comes from.
Which one uses elapsed time and distance?
The pace calculator. It solves pace, time or distance, converts speeds, works out cumulative or lap splits and projects a finish time at a constant pace. Everything is plain arithmetic on the distances and times you enter.
Are my results stored, and are they a medical plan?
Your inputs stay in your browser and are not stored. The results are arithmetic estimates for healthy adults, not a medical plan, a diagnosis or a promise about weight or performance. If a result affects a health decision, ask a doctor or a registered dietitian.