How much water should I drink in a day?

by | Aug 16, 2023 | #StripTheNonsense

Not sure if you’re staying hydrated enough and wondering exactly how much water should I drink in a day.

Well, it’s good that you’re questioning it because getting enough fluid is important for our body to function at its best.

Whilst we don’t love the diet culture narrative that often tells us we’re probably thirsty, not hungry (if you’re hungry, you need food, not water!), being adequately hydrated is key for us to feel good in our bodies day to day. 

Our bodies are made up of roughly 50-60% water though this varies depending on sex, age and body composition.

Water is needed for most of your body functions including: 

  • Maintaining the health and integrity of each of the cells in your body
  • Keeping the blood liquid enough to flow properly through your body
  • Helping eliminate the by-products of the body’s metabolism which would become toxic if kept too long in the body (e.g electrolytes and urea)
  • Regulating body temperature through sweat
  • Lubricating and cushioning joints
  • Reducing the risk of urinary tract infections (UTIs), by keeping the bladder clear of bacteria
  • Assisting healthy digestion and preventing constipation
  • Moisturising your skin, maintaining texture and appearance
  • Carrying nutrients and oxygen to your cells.
  • Acting as a shock absorber inside the eyes, spinal cord, around the brain and in the amniotic sac surrounding the foetus in pregnancy

So, hopefully, you see just how important it is to drink enough water in a day. But exactly how much do you need?

How many litres of water a day?

The NHS recommends a blanket guideline to drink 6-8 glasses of fluid per day. 

Assuming these are standard 300ml glass, this would equal around 1.8-2.4L/day that the NHS recommends.

Remember water, milk, squash, tea and coffee (and all fluids except alcohol) all count toward your total intake.

For a more individualised daily water target, you may like to use the equation below.

How much should you drink a day calculator

Drinking to thirst is usually one of the best gauges.

However, if you would like something to aim for, you could use the equation below to calculate an estimate. And then Goldilocks it! Was it too much, too little, just right?

Now, this equation uses body weight. We know that not everyone knows their weight or wants to, and that is fine! There is no need to weigh yourself, especially if you know it may trigger you. If you don’t there are alternatives to figure out how much water is right for you. 

For example, you can go off the colour of your pee. Aim for it to be a light yellow colour. In general, a dark yellow means you could do with more water.

If you do have an idea of your weight, you can use this simple calculation to figure out roughly how much water you should drink in a day.

Your Weight (in Kg) x 0.035 = Water to drink per day (in L)

For example, if you are about 60kg, aim for around 2 litres of water every single day. At 90kg, you can aim for around 3 litres of water.

Remember this is just an estimate. If you are thirsty for more, then of course go ahead and have more. Also, if it is a particularly hot day or you are doing lots of physical activity, you may need more fluids.

5 Tips for getting enough water in a day

If you struggle to get enough fluid, see if any of these tips sound like they might be helpful…

  1. Use a bottle and aim to get through however many refills/day you need to meet your target
  2. Set regular reminder alarms on your phone to prompt you to drink
  3. Not a fan of plain water? Try infusing water overnight with fresh berries, mint, ginger, cucumber and lemon or sugar-free squash.
  4. Have a drink with each meal and snack
  5. Test out one of the many apps that are now available to help you track your fluid intake throughout the day

Share this article

Stop Obsessing and Regain Control With Food: Your 7-day Guide

Food Freedom
By Katherine Kimber, Registered Dietitian

More articles

Feeding you the latest fad-free
non-diet health and nutrition support

Our regular emails are filled with freebies, actionable tips, resources and insights on
how to improve your relationship with food, that you won’t find anywhere else!

10 + 6 =