- Daily Water Target: enter your weight and sex (and, if you like, your age and how active or hot your day is) to estimate how much water you would normally need in a day.
- Hydration Check: look at the colour of your urine and tap the closest shade on the scale. Add your weight to also get a rough estimate of your current fluid deficit and how much to drink now.
- If you are on a fluid restriction for kidney or heart disease, switch that on — the tool will then point you to your prescribed limit instead of giving a "drink this much" number.
These are rough estimates for general guidance, not medical advice. Everything runs in your browser; nothing is stored or sent anywhere.
Why staying hydrated matters
Water keeps your blood pressure steady, helps your kidneys flush out waste, prevents constipation, and lowers the risk of kidney stones and urine infections. Even mild dehydration can cause tiredness, headache, poor concentration, dizziness on standing, and dark, strong-smelling urine. Older adults feel thirst less reliably, so colour can be a more useful guide than thirst alone.
Urine colour is a quick window on hydration
Pale, plentiful urine usually means you are well hydrated; darker yellow usually means you need to drink more. It is a guide, not a lab test — colour can be changed by food, vitamins and medicines (see below).
Important if you have kidney or heart disease
More water is not always better
If you have advanced kidney disease, are on dialysis, or have heart failure, you may be on a fluid restriction — a daily limit set by your care team. Drinking "to clear the colour" can be harmful, and urine colour is an unreliable guide because damaged kidneys cannot concentrate urine well and water pills (diuretics) change it. Always follow the limit you were given, and switch on the fluid-restriction option in the tools below.
Your Daily Water Target
Estimate how much fluid you would normally need in a day from your weight and sex. This is a healthy starting point for most people — your needs go up in hot weather, with exercise, and during fever, vomiting or diarrhoea.
💧 Estimated from about 30–35 mL of fluid per kg of body weight per day (older adults ~30 mL/kg), shown as a range from drinks; roughly another 20% comes from food. Cross-checked against general adequate-intake references (men ≈ 2.5 L, women ≈ 2.0 L total water per day). A guide for generally healthy people — not for anyone on a prescribed fluid limit.
Urine-Colour Hydration Check
Tap the colour closest to your urine. Check it in good light, in a clear container or against white tissue — and ideally not your very first morning urine, which is normally darker. Add your weight to also get a rough estimate of how much fluid you are short and how much to drink now.
💧 Colour bands follow the validated urine-colour scale (Armstrong). The litre estimate maps each band to an approximate body-water deficit (mildly dehydrated ≈ 1%, dehydrated ≈ 2–3%, very dehydrated ≈ 3–5% of body weight) and multiplies by your weight. This is a rough self-check, not a measurement — colour is changed by foods, vitamins and medicines, and is unreliable in kidney disease.
What can change the colour of my urine?
Some foods, medicines and supplements can change your urine colour even when you are perfectly hydrated — so use the colour scale as a guide, not a verdict.
🥦 Foods & drinks
Beetroot and blackberries (pink/red), carrots (orange), fava beans and rhubarb (dark), lots of coffee or tea. Asparagus can add a smell.
💊 Vitamins & supplements
B-vitamins (especially B2/riboflavin) turn urine bright or neon yellow; high-dose vitamin C and some herbal products can also alter colour.
💉 Medicines
Rifampicin and some laxatives (orange), certain antibiotics, phenazopyridine (orange-red), and water pills (diuretics), which keep urine pale even when you are dry.
🩺 Health conditions
Kidney disease (urine can stay pale even when dehydrated), liver problems (dark tea-colour), urine infections (cloudy), and blood in the urine (pink/red/brown).
When colour is unreliable
In moderate-to-advanced kidney disease the kidneys cannot concentrate urine, so it may look pale even when your body is short of water. If you have kidney disease, do not rely on colour alone — follow your care team's advice.
🚩 Drink fluids and seek medical help urgently if you have
Infants, older adults, pregnant women, and people with kidney, heart or diabetes problems can become dehydrated quickly — get help early.
Tips to drink enough through the day
- Spread drinks across the day rather than gulping a lot at once — sip the estimated top-up over 2–4 hours.
- Keep a bottle in sight; drink a glass with each meal and medicine.
- Drink extra before, during and after exercise and on hot days; water is best for everyday hydration.
- Watch for early thirst, dark urine, dry lips and headache as cues to top up.
- If you are on a fluid restriction, do not use these top-up amounts — keep to your prescribed daily limit and manage thirst with ice chips, sour sweets or rinsing your mouth.
How the estimates are made & references
Daily water target
| Quantity | How it is estimated |
|---|---|
| Daily fluid from drinks | ≈ 30–35 mL × body weight (kg); older adults use ≈ 30 mL/kg |
| Total water (incl. food) | ≈ drinks + 20% (about a fifth of water comes from food) |
| Hot weather / activity | add ≈ 0.5–1 L; fever, vomiting or diarrhoea add more |
| Reference adequate intake | men ≈ 2.5 L, women ≈ 2.0 L total water/day (EFSA); IOM lists higher (men ≈ 3.7 L, women ≈ 2.7 L) |
Urine colour → fluid deficit
| Colour band | Status | Approx. deficit | Suggested drink now |
|---|---|---|---|
| 1–2 | Well hydrated | ~0% | Keep drinking at your usual rate |
| 3–4 | Mildly dehydrated | ~1% of body weight | 1 glass (~250 mL) |
| 5–6 | Dehydrated | ~2–3% | 2–3 glasses (~500–750 mL) |
| 7–8 | Very dehydrated | ~3–5% | A large bottle (~750 mL–1 L); seek help if unwell |
Deficit (litres) ≈ deficit % × body weight (kg) ÷ 100 (since about 1 kg of body weight lost as water ≈ 1 litre). Replace gradually over a few hours alongside normal drinking — do not drink very large volumes quickly.
Notes & references
Urine colour correlates with hydration status (urine specific gravity and osmolality) in healthy adults, which is the basis of urine-colour charts; the relationship weakens in kidney disease and with diuretics. These tools give rough, population-level estimates for general guidance only.
- Armstrong LE, et al. Urinary indices of hydration status. Int J Sport Nutr. 1994;4(3):265-279.
- Perrier ET, et al. Urine colour change as an indicator of change in daily water intake. Eur J Nutr. 2016.
- EFSA Panel on Dietetic Products, Nutrition, and Allergies. Scientific opinion on dietary reference values for water. EFSA Journal. 2010;8(3):1459.
- Institute of Medicine. Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. Washington, DC: National Academies Press; 2005.
- Healthdirect Australia. Urine colour chart — "Am I drinking enough water?" (concept reference), 2024.
