Pregnancy hydration calculator

Your body needs a little more water in pregnancy. Here is a daily drinks guide, with extra for hot days and activity, in glasses you can count.

Your details

A daily drinks guide in pregnancy

1.8

litres a day from drinks, about 7 glasses

Total water, food included (EFSA)2.3 litres
Extra for heat or activitynone added
Drinks so far (tea and coffee count)0.5 litres
Still to drink today1.3 litres, about 5 glasses
Caffeine so far175 mg of the NHS 200 mg a day
In pints3.2

Water, milk and decaf all count, and so do soups and juicy fruit. Pale straw coloured pee is a good sign.

Being sick so often you cannot keep fluids down, very dark pee or no pee for 8 hours needs help: call your midwife, GP or 111.

The working

2.3 litres, most of it from drinks

EFSA sets total water for women at 2.0 litres a day, plus 300 ml in pregnancy: 2.3 litres. About 80% usually comes from drinks, which is 1.8 litres, roughly 7 glasses. A hot day adds about half a litre.

Tea and coffee count towards it. A mug of instant coffee and a mug of tea are about half a litre, leaving 1.3 litres (5 glasses) to go, and 100 + 75 = 175 mg of caffeine, inside the NHS 200 mg a day for pregnancy. Two mugs of filter coffee alone would be 280 mg.

What counts

More than water

Water, milk and decaf tea or coffee
Soups, yogurt and juicy fruit
Fruit juice and smoothies: 150 ml a day, as they are sugary
Limit caffeine to 200 mg a day

Signs to watch

Dehydration in pregnancy

Dark yellow pee, headaches, dizziness and constipation can mean you need more. Being sick often in early pregnancy can quickly dehydrate you.

Everything you have drunk

Water, cans and the rest of the day

Add glasses of water and any cans so far and we count them too. With a mug of instant coffee, a mug of tea, 2 glasses of water, a can of cola and a 250 ml energy drink, you have had about 1.6 litres, leaving about 0.3 litres of the 1.8 litres from drinks. The caffeine is 100 + 75 + 40 + 80 = 295 mg, over the NHS 200 mg a day. Add the waking hours left and we spread what is left across them: 0.3 litres over 8 hours is about 32 ml an hour.

Read with care

What this cannot tell you

Medical conditionsHeart or kidney conditions may change your fluid needs.
SwellingDrinking less will not reduce pregnancy swelling.
SicknessSevere sickness needs medical help.

Questions

Common questions

How much water should I drink when pregnant?

About 1.8 litres of drinks a day, more when it is hot.

Does tea count towards my water intake?

Yes, though keep an eye on caffeine.

Can dehydration cause problems in pregnancy?

It can cause headaches, constipation and dizziness; severe dehydration needs help.

Sources

Last checked 21 October 2026. Spotted something wrong? Tell us and we will fix it.