Hydration Calculator — How Much Water Should I Drink?

Q: Signs of dehydration

Mild: Thirst, dark yellow urine, dry mouth, headache, tiredness Moderate: Decreased urine output, dizziness, dry skin, rapid heartbeat Severe (seek medical help): Very little or no urine, extreme thirst, confusion, rapid breathing, fainting Children, elderly people, and people with chronic conditions are at higher risk of dehydration. In Australian heatwaves, dehydration can become dangerous quickly. Keep water accessible and drink regularly.

Your recommended daily water intake

From drinks

~80% of total

From food

~20% of total

💡 Hydration tips

Carry a water bottle. Having water visible and accessible is the simplest way to drink more throughout the day.

Check your urine. Pale straw colour = well hydrated. Dark yellow = drink more. Clear = you may be over-hydrating.

Food counts too. About 20% of your daily water comes from food, especially fruits and vegetables like watermelon, cucumber, oranges, and lettuce.

Tea and coffee count. Despite being mild diuretics, tea and coffee still contribute to your hydration. They don't "dehydrate" you at normal consumption levels.

Drink before you're thirsty. By the time you feel thirsty, you may already be mildly dehydrated — especially in hot weather or during exercise.

The NHMRC Nutrient Reference Values recommend an Adequate Intake (AI) of total water (from all sources including food):

Men: 2.6 L/day from beverages (~10 cups)

Women: 2.1 L/day from beverages (~8 cups)

Pregnant women: 2.3 L/day

Breastfeeding women: 2.6 L/day

These are general guidelines. Individual needs vary based on body size, activity, climate, and health conditions. People who exercise heavily, work outdoors, or live in hot climates may need significantly more.

Mild: Thirst, dark yellow urine, dry mouth, headache, tiredness

Moderate: Decreased urine output, dizziness, dry skin, rapid heartbeat

Severe (seek medical help): Very little or no urine, extreme thirst, confusion, rapid breathing, fainting

Children, elderly people, and people with chronic conditions are at higher risk of dehydration. In Australian heatwaves, dehydration can become dangerous quickly. Keep water accessible and drink regularly.

Counts: Water, tea, coffee (yes — the myth is wrong), milk, juice, sparkling water, soup, herbal tea, flavoured water.

Counts but not ideal: Soft drinks, energy drinks, sports drinks (unnecessary for most people), alcohol (net diuretic effect at higher amounts).

Food sources (~20% of intake): Watermelon, cucumber, oranges, strawberries, lettuce, tomato, yoghurt, soup.

Water is always the best choice — no calories, no sugar, no cost.