Calculators
Fluid intake calculator
This fluid intake calculator gives you a rough daily guide to how much fluid your body needs. It takes about a minute.
Fluids aren’t only water. Tea, coffee, milk and soup count, and so does the water in your food. The result is a guide, not a prescription.
Use the fluid intake calculator
Got a fluid limit? If your care team has told you to limit fluids, follow their advice instead. Some health conditions and medications come with fluid limits, and a general calculator can’t know about them.
Your daily fluid guide
0 litres about 0 cups of 250 mL, from drinks
- Drinks: 0 L (about 70%)
- Food: about 0 L (about 20%)
- Made by your body: about 0 L (about 10%)
A rough guide, not a prescription. Tea, coffee, milk and soup all count. Thirst, the colour of your wee and your care team’s advice fill in the rest.
Follow your care team’s limit
If you’ve been given a fluid limit, that number comes first. A general calculator can’t know about your condition or medications, so we won’t show one here. If you’re not sure what your limit is, or it’s hard to stick to, ask your GP, specialist or dietitian.
Where it comes from
Where your water comes from
Your body can’t store much water, so you top it up every day to replace what you lose through your skin, breath, wee and poo. Roughly:
70%
Drinks
About 70% of what you need.
20%
Food
About 20%. Even dry-looking food holds some water.
10%
Made by your body
About 10%, a small amount produced during digestion.
Source: Better Health Channel, Water: a vital nutrient. Daily fluid guides in the calculator are based on the NHMRC Nutrient Reference Values.
Why your needs change
How much you need shifts with how active you are, your body size, what you eat, the weather and whether you’re unwell. Treat the calculator’s number as a starting point. Thirst, the colour of your wee and your care team’s advice fill in the rest.
What counts as fluid
Water, sparkling water, tea, coffee, milk, soup, broth, smoothies, ice blocks and jelly all count. So does the water in your food. If plain water is hard going, that’s a lot of other options.
Low effort, still counts
Low-effort ways to get more in
These are ideas, not rules:
- Fill a bottle or jug once and keep it where you’ll actually sit.
- Use a lidded cup or a straw if lifting a full glass is hard.
- Pair a hot drink with something you already do.
- Keep a few cartons of soup or broth in the cupboard. It counts, and it’s food too.
- Freeze juice or cordial into ice blocks.
Hydration and pain
There’s early research on hydration, electrolytes and chronic pain. Interesting isn’t the same as proven, and I wouldn’t treat it as a fix. If you’re thinking about electrolyte products, ask your care team first, especially if you take medication or have fluid limits.
Looking at food as well as drink?
Try the macro calculator or browse all our calculators. For advice that fits your health, a GP or an Accredited Practising Dietitian can help, and our Editorial, Health and Sourcing Policy explains how we handle health information.
