Health & fitness

Quick estimates for BMI, body fat, calories, and heart rate — all in your browser.

BMI Body fat Calorie planner Calorie deficit Calorie surplus Water intake Hydration schedule Pre-workout hydration Sweat rate Workout hydration plan Hydration bottle plan Electrolyte bottle plan Electrolyte drink mix Carb drink mix Gel carb schedule Session fueling plan Aid station fueling plan Race fueling pack list Drop bag fueling plan Crew handoff fueling plan Post-race refuel plan Next-day recovery plan Multi-day recovery plan Return to training check Training ramp plan Comeback week schedule Training load rebuild Sodium loss estimator Rehydration plan Dehydration percent Electrolyte needs Meal calorie split Protein per meal Macro per meal Macro calculator Protein intake Ideal weight Heart rate zones Due date
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How to choose (25 checks)

  1. Start with BMI for a simple weight/height overview.
  2. For daily calories, use the calorie planner.
  3. If maintenance and target calories are already known, use Calorie Deficit to pressure-test the daily gap before you lock macros.
  4. If the plan is for gaining and maintenance plus target intake are already known, use Calorie Surplus to pressure-test the daily surplus before you lock macros.
  5. If calories are not the question and you first need a hydration baseline for the day, use Water Intake before detailed nutrition planning.
  6. If the daily water target is already fixed and the next job is timing it across the day, use Hydration Schedule after Water Intake.
  7. If the remaining question is what to drink before one workout starts, use Pre-Workout Hydration Plan after the daily baseline and before the during-workout page.
  8. If the question is how much fluid one training session actually cost you, use Sweat Rate after the session data is available, then loop back to Water Intake or Hydration Schedule to update the plan.
  9. If session loss is already known and the missing step is what to do during the workout itself, use Workout Hydration Plan before you hand the remaining liters to recovery.
  10. If the during-workout pace already looks realistic and the next question is how many bottles to start with or whether one refill point is enough, use Hydration Bottle Plan after Workout Hydration Plan.
  11. If bottle count and sodium context already look believable and the remaining question is what should go into each bottle, use Electrolyte Bottle Plan between bottle logistics and recovery planning.
  12. If the per-bottle sodium target already looks believable and the remaining question is how many tabs, scoops, or servings that means in the actual bottle, use Electrolyte Drink Mix after Electrolyte Bottle Plan.
  13. If the bottle flow already looks believable and the remaining question is how many carb scoops or servings belong in each bottle, use Carb Drink Mix after bottle planning and next to Electrolyte Drink Mix.
  14. If bottle carbs already look believable and the remaining question is when gels should cover the remaining carbs across the session, use Gel Carb Schedule after Carb Drink Mix.
  15. If fluid, sodium, bottle count, and gel timing already look believable and the remaining question is how to run them as one field note, use Session Fueling Plan after Gel Carb Schedule.
  16. If the combined session note already looks believable and the remaining question is how bottles, gels, and refills map onto real aid stations, use Aid Station Fueling Plan after Session Fueling Plan.
  17. If the aid-station flow already looks believable and the remaining question is what should physically go into the vest, belt, or drop bag, use Race Fueling Pack List after Aid Station Fueling Plan.
  18. If the total inventory already looks believable and the remaining question is what reserve supplies should wait at each drop-bag checkpoint, use Drop Bag Fueling Plan after Race Fueling Pack List.
  19. If drop-bag placement already looks believable and the remaining question is what a support crew member should hand you at each crew-access point, use Crew Handoff Fueling Plan after Drop Bag Fueling Plan.
  20. If race-day logistics already look believable and the remaining question is what to drink and eat first after the finish before normal meals resume, use Post-Race Refuel Plan after Crew Handoff Fueling Plan or Rehydration Plan.
  21. If the finish-line refuel already looks believable and the remaining question is how to bridge dinner, pre-bed intake, breakfast, and the next-morning top-up, use Next-Day Recovery Plan after Post-Race Refuel Plan.
  22. If the next-morning bridge already looks believable and the remaining question is how to structure day 1 to day 3 fluid, carbs, protein, and training readiness, use Multi-Day Recovery Plan after Next-Day Recovery Plan.
  23. If that day-1-to-day-3 recovery block already looks believable and the remaining question is whether easy or reduced training can restart yet, use Return to Training Check after Multi-Day Recovery Plan.
  24. If the go / reduce / wait decision already looks believable and the remaining question is how to cap the first session and the first comeback week, use Training Ramp Plan after Return to Training Check.
  25. If the first-session cap already looks believable and the remaining question is how to spread day 1, day 3, day 7, rest, and cross-training across the whole first week back, use Comeback Week Schedule after Training Ramp Plan.
  26. If that first comeback week already looks believable and the remaining question is how far weeks 2 to 4 can rebuild total load, long-session size, and quality work, use Training Load Rebuild after Comeback Week Schedule.
  27. If sweat rate already looks believable and the next question is how large sodium loss may be before you choose drink composition, use Sodium Loss Estimator before Electrolyte Needs.
  28. If the session loss is already known and the next job is how to replace it over the next hours, use Rehydration Plan after Sweat Rate.
  29. If the session loss is already known and you first want to judge how large that loss was relative to starting body weight, use Dehydration Percent before finalizing rehydration.
  30. If session loss is already known and the open question is whether plain water is still enough or electrolytes should move up in priority, use Electrolyte Needs before you finalize the recovery drink plan.
  31. If the daily intake is already fixed and the remaining job is meal-by-meal execution, use Meal Calorie Split before detailed protein or macro work.
  32. If you only need a daily protein range by body weight and goal, use Protein Intake before detailed macro planning.
  33. If the daily protein target is already fixed and you want meal-by-meal gram targets, use Protein Per Meal before the final macro split.
  34. If daily protein, carbs, and fat are already fixed and you want a meal-by-meal execution table, use Macro Per Meal after Protein Per Meal.
  35. If calories are already set and you need gram targets, use the macro calculator.
  36. For a body fat estimate, use the body fat calculator.
  37. For training intensity, check heart rate zones.

Note: Results are for educational use only and may not reflect medical advice.

Use the health calculators as a sequence, not as isolated pages

This topic is easiest when you split the job into two questions: what is the current baseline, and what intake or training target are you trying to set. For weight-management work, the clean path is to estimate maintenance, choose a calorie target, pressure-test the daily deficit or surplus, set a protein floor, and only then lock a full macro split. Ideal weight belongs earlier in the process as a goal-range reference, not as a daily intake calculator.

Recommended calorie-planning path

  1. Use BMR & TDEE or Calorie Planner when maintenance calories or the target itself are not fixed yet.
  2. Use Calorie Deficit once maintenance and target intake are already known and you want to test a cutting gap.
  3. Use Calorie Surplus once maintenance and target intake are already known and you want to test a gaining surplus.
  4. Use Water Intake when the missing baseline is hydration rather than calories, protein, or macros.
  5. Use Hydration Schedule after daily liters are already fixed and the remaining job is distributing water across real drink windows.
  6. Use Pre-Workout Hydration Plan after the daily schedule is clear when the next question is what should happen in the one to four hours before training starts.
  7. Use Sweat Rate after training when you want session-specific fluid loss from weigh-in and drink data instead of a generic daily baseline.
  8. Use Dehydration Percent after session loss is known when the next question is how large that loss was relative to starting body weight.
  9. Use Workout Hydration Plan when session loss is already known and the remaining question is the drink rhythm during the session rather than before or after it.
  10. Use Hydration Bottle Plan after the during-session pace is roughly acceptable and the remaining question is bottle count, bottle size, or refill logistics.
  11. Use Electrolyte Bottle Plan after bottle count and sodium context already look believable and the remaining question is how much sodium belongs in each bottle.
  12. Use Electrolyte Drink Mix after the per-bottle sodium target is already believable when the remaining step is translating that target into tabs, scoops, or serving fractions.
  13. Use Carb Drink Mix after the bottle count already looks believable when the remaining step is translating per-bottle carbs into practical scoops or serving fractions.
  14. Use Gel Carb Schedule when bottle carbs already look believable and the remaining step is deciding when gels should cover the remaining hourly carbs across the session.
  15. Use Session Fueling Plan when bottle carbs and gel timing already look believable and the remaining step is one combined checkpoint-by-checkpoint field note.
  16. Use Aid Station Fueling Plan when that field note already looks believable and the remaining step is mapping bottles, gels, and refill decisions onto actual aid-station timing.
  17. Use Race Fueling Pack List when the station logic already looks believable and the remaining step is packing actual bottles, mix servings, gels, tabs, and backup margin.
  18. Use Drop Bag Fueling Plan when the total inventory already looks believable and the remaining step is assigning reserve supplies to specific drop-bag checkpoints.
  19. Use Crew Handoff Fueling Plan when drop-bag placement already looks believable and the remaining step is deciding what a support crew member should hand you at each crew point.
  20. Use Post-Race Refuel Plan when race-day logistics already look believable and the remaining step is bridging the finish line to the first drink, snack, and proper meal.
  21. Use Next-Day Recovery Plan when the finish-line refuel already looks believable and the remaining step is turning the same recovery target into dinner, pre-bed, breakfast, and next-morning top-up blocks.
  22. Use Multi-Day Recovery Plan when the next-morning bridge already looks believable and the remaining step is spreading the same recovery target across day 1 to day 3 without returning to normal training too early.
  23. Use Return to Training Check when the multi-day recovery block already looks believable and the remaining step is deciding whether training should restart as easy, reduced, or delayed work.
  24. Use Training Ramp Plan when the return / reduce / wait decision already looks believable and the remaining step is setting the first session type, first-session minutes, first-week volume cap, and comeback-week recovery guardrails.
  25. Use Comeback Week Schedule when that first-session ramp already looks believable and the remaining step is laying out the whole first seven days back.
  26. Use Training Load Rebuild when the first comeback week already looks believable and the remaining step is deciding how weeks 2 to 4 should rebuild total load, long-session size, and quality-session limits.
  27. Use Sodium Loss Estimator after sweat rate is already believable when the next question is the rough sodium range behind that fluid loss.
  28. Use Rehydration Plan after session loss is known and you need a practical replacement schedule with larger early drinking blocks.
  29. Use Electrolyte Needs after session loss or sodium context is known when the remaining question is whether recovery still looks like plain water first, mixed support, or electrolyte-priority.
  30. Use Meal Calorie Split when the daily calorie target is fixed and you need a practical breakfast / lunch / dinner plan.
  31. Use Protein Intake to set a body-weight-based protein checkpoint before you decide the full split.
  32. Use Protein Per Meal when the daily protein number is fixed and you want practical breakfast / lunch / dinner gram targets.
  33. Use Macro Calculator to lock the final daily protein, carb, and fat grams.
  34. Use Macro Per Meal when the daily PFC totals are already fixed and you want a meal-by-meal execution table.

When to use another page first

Checks before you trust the output

See also

If you are unsure where to start, these cover the most common tasks.

BMI

Quick BMI with category and unit support.

Open

Calorie planner

Estimate calorie needs with activity and goals.

Open

Body fat

Estimate body fat % from measurements.

Open

Calculators

Choose the health page by the decision you need to make

This hub is for picking the right health or fitness calculator before you start entering numbers. Start with the type of question: body metric, calorie planning, workout pacing, or classroom-style health screening.

Where to go first

When to leave this hub

Move to date/time or finance topics when the question becomes scheduling, budgeting, or lifestyle planning rather than a health metric itself.

FAQ

Which section should I open first?

Open the branch that matches your decision: body metric, calorie planning, workout pacing, or planning support. That is faster than scanning every calculator name.

Are these pages suitable for diagnosis or treatment decisions?

No. These pages are for planning, education, and quick screening-style checks. Medical diagnosis and treatment decisions still require professional care.

Why do two health calculators sometimes seem inconsistent?

They often measure different things or use different assumptions. Compare the purpose of the page first, then compare the numbers.

Can I share a result with someone else?

Yes, when the page supports share URLs. Keep in mind that shared links may contain your input settings, so avoid putting personal medical details into them.

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