Mayo Clinic Water Calculator
Mayo clinic water calculator works out Fluid to drink and Baseline requirement from Units, Age and Sex. The default figures on this page give fluid to drink of 2,960 mL/day; change any entry and the result, the working and the sources update together.
Your figures
Updates as you typeHow this is worked out
3 steps
- DRI band: Adults 19 and over. Adequate intake for total water = 3.7 L/day.
- Water in food supplies the rest, so the amount to drink = 3700 x 0.8 = 2960 mL/day.
- Total to drink = 2960 mL/day = 2.96 L = 12.5 eight-ounce cups
Its 5 worked examples are re-run on every release, last on 15 September 2026. What changed
Sources and references
4 sources
Keep this result
Save it, change one figure, then compare the two
The calculation stays free. Save this scenario, adjust one assumption, save that too, and put them side by side to see exactly what the change costs you. A free account keeps 5 scenarios and 2 comparisons; Personal makes both unlimited and adds exports and private links. Nothing is saved unless you press Save.
What the mayo clinic water calculator calculates
Daily fluid requirement from the National Academies Dietary Reference Intakes, a millilitres-per-kilogram rule or the Holliday-Segar maintenance formula, with additions for exercise, heat and pregnancy.
How to use this mayo clinic water calculator
Enter Units, Age, Sex and Pregnancy or breastfeeding. Fluid to drink updates as you type. Change one figure at a time to see what drives the result.
How the result is worked out
Open “How this is worked out” beside the result for the step-by-step calculation behind Fluid to drink, Baseline requirement and Added for exercise.
The method follows Institute of Medicine (now NASEM), Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate, National Academies Press, Mayo Clinic, Water: how much should you drink every day?, Holliday MA & Segar WE, The maintenance need for water in parenteral fluid therapy, Pediatrics 1957;19:823-832 - the 100/50/20 mL/kg rule and American College of Sports Medicine position stand, Exercise and Fluid Replacement, Med Sci Sports Exerc 2007;39:377-390 - sweat rates typically 0.5 to 2.0 L per hour, replaced according to individual sweat loss.
What you can compare
Change one input at a time to see how it affects Fluid to drink, Baseline requirement and Added for exercise. The inputs you can vary are Units, Age, Sex, Pregnancy or breastfeeding, Body weight and Extra pounds.
Understanding Fluid to drink, Baseline requirement and Added for exercise
These are population reference intakes, not a prescription. Heart failure, kidney disease, liver disease and some medications require a fluid restriction rather than a target, and drinking far above requirement can cause dangerous hyponatraemia. Ask a clinician before changing fluid intake for a medical reason.
Results are general information, not financial, tax, legal, medical or engineering advice. Check any decision that matters with a qualified professional.
See something wrong? Report a problem with this calculator
Frequently asked questions
How can I calculate how much water I should drink daily?
Daily fluid requirement from the National Academies Dietary Reference Intakes, a millilitres-per-kilogram rule or the Holliday-Segar maintenance formula, with additions for exercise, heat and pregnancy. Open “How this is worked out” beside the result to see each step for your own figures.
What drinks hydrate better than water?
Daily fluid requirement from the National Academies Dietary Reference Intakes, a millilitres-per-kilogram rule or the Holliday-Segar maintenance formula, with additions for exercise, heat and pregnancy. On this page it is computed from Units, Age and Sex and shown as Fluid to drink, Baseline requirement and Added for exercise.
What information do I need for the mayo clinic water calculator?
You need Units, Age, Sex, Pregnancy or breastfeeding, Body weight, Extra pounds, Share of total water that comes from drinks and Exercise. The page opens with default figures that give fluid to drink of 2,960 mL/day, so you can see the scale before entering your own.
What does this mayo clinic water calculator show?
It shows Fluid to drink, Baseline requirement, Added for exercise, Added for heat, altitude or illness, Total water including water in food (DRI method), Reference band used and Method used, with the working and any warnings for your entries.
Can I check how the mayo clinic water calculator result was calculated?
Yes. The “How this is worked out” section shows the calculation steps, and the sources section identifies the references used for the method.