How much ORS should I give my child?
Oral rehydration solution (ORS) replaces the water and salts a child loses with diarrhoea, and it is the treatment the World Health Organization and UNICEF recommend for preventing and treating dehydration. This ORS calculator gives the amounts from the WHO treatment manual: how much to give after each loose stool when a child is not dehydrated (Plan A, at home), and how much is usually needed over the first four hours when a child has some dehydration (Plan B, with a health worker), by age and by weight.
Diarrhoea can become dangerous quickly, especially in babies. The warning signs at the top of the page come first: if any apply, get help now rather than calculating amounts. Everything here is information only and does not replace your doctor, nurse or health worker.
How to use the ORS calculator
- Check the danger signs first. If any apply, seek urgent care.
- Choose your child’s age and, if you know it, the weight in kg or lb.
- Pick Plan A if there are no signs of dehydration, or Plan B if a health worker has said there is some dehydration.
- For Plan A, enter the loose stools so far today to see the extra fluid so far; for Plan B, read the 4-hour total and the amount per hour and per 15 minutes.
ORS Calculator & Fluids Guide for Kids features
WHO Plan A by age
Amounts after each loose stool, in mL, cups and teaspoons.
WHO Plan B by weight or age
Weight × 75 mL over 4 hours, checked against the WHO weight and age bands.
Pacing
Per hour and per 15 minutes, with the WHO spoon-and-cup method for small children.
Prominent danger signs
Emergency and same-day signs from WHO and the NHS above the calculator.
ORS composition
What is in one litre of WHO low-osmolarity ORS.
WHO amounts at a glance
Worked example: a 10 kg toddler with some dehydration needs about 10 × 75 = 750 mL in the first four hours — roughly 190 mL an hour, or a teaspoon every minute or two. Once rehydrated, the same child needs 50–100 mL after each loose stool.
| Age (weight) | Plan A: after each loose stool | Plan B: first 4 hours |
|---|---|---|
| Under 4 months (under 5 kg) | 50–100 mL | 200–400 mL |
| 4–11 months (5–7.9 kg) | 50–100 mL | 400–600 mL |
| 12–23 months (8–10.9 kg) | 50–100 mL | 600–800 mL |
| 2–4 years (11–15.9 kg) | 100–200 mL | 800–1,200 mL |
| 5–14 years (16–29.9 kg) | 100–200 mL up to 10 years, then as much as wanted | 1,200–2,200 mL |
| 15 years or older (30 kg+) | As much as wanted | 2,200–4,000 mL |
Giving ORS, zinc and food
- Use a clean cup or spoon, not a feeding bottle. Under 2 years, give a teaspoonful every 1–2 minutes; older children can sip often. If the child vomits, wait 5–10 minutes and continue more slowly.
- WHO recommends zinc, 10–20 mg a day for 10–14 days, for children with diarrhoea; your health worker gives the right dose for your child’s age.
- Keep breastfeeding and keep feeding; do not dilute formula. Avoid soft drinks, packaged fruit juices, sweetened tea and coffee, which can make diarrhoea worse.
- The NHS advises not giving medicines to stop diarrhoea to children under 12 unless a doctor prescribes them.
Can I make ORS at home?
Packets of WHO-formula ORS are cheap and widely sold in pharmacies (in India, look for the WHO formula on the packet). The WHO manual notes that a home-made solution of 3 g of table salt (one level teaspoon) and 18 g of sugar in 1 litre of clean water works, but it is not generally recommended because the recipe is often forgotten or mis-measured and too little may be given. Too much salt is dangerous for babies — use packets where you can, and never guess the amounts.
ORS Calculator & Fluids Guide for Kids FAQ
How much ORS should I give a 6-month-old baby?
For a baby without signs of dehydration, WHO advises 50–100 mL after each loose stool, given slowly with a spoon, while breastfeeding continues. A baby this young with diarrhoea should be seen by a doctor or health worker the same day.
Is ORS safe for a baby under 1 year?
Yes, WHO low-osmolarity ORS is designed for all ages, including young babies, mixed exactly as the packet says. Babies under 12 months should still be checked by a health professional.
How do I make ORS with 1 litre of water?
Empty one 1-litre packet into exactly 1 litre of clean, boiled and cooled water and stir until dissolved. If your packet is for 200 mL, use 200 mL.
What are the signs of dehydration in a child?
Restlessness or irritability, sunken eyes, eager thirst and skin that goes back slowly when pinched suggest some dehydration; drowsiness, being unable to drink and skin that goes back very slowly are signs of severe dehydration — an emergency.
Can I give sports drinks or juice instead?
They are not a substitute: they have too much sugar and too little salt and can worsen diarrhoea. Use ORS.
Is this ORS calculator medical advice?
No. It is information only, based on WHO guidance as of October 2026. Always follow your doctor or health worker.