How many scoops of formula per ounce of water?

For most US powders, half a scoop per fluid ounce: 1 level scoop per 2 fl oz, so 4 oz takes 2 scoops and 8 oz takes 4. Most UK and European powders use 1 scoop per 30 mL (1 fl oz). Check the mixing table on your own tin, because scoop sizes differ.

How many scoops for a 6 oz bottle?

With a 1 scoop per 2 fl oz label, 6 fl oz of water takes 3 level scoops. With a 1 scoop per 30 mL label, 180 mL takes 6 scoops.

Should I add water or powder first?

Water first, then powder. Labels give the amount of water to measure before the powder goes in; adding powder first and topping up to a line makes the formula too concentrated.

Can I add extra water to make formula last longer?

No. Watering down formula can cause poor growth and a dangerous drop in blood sodium (water intoxication) that may lead to seizures. Too little water is also harmful. Mix exactly as the label says and talk to your pediatrician, WIC office or a food bank if formula is hard to afford.

How much formula does a baby need per day?

A common guide from the American Academy of Pediatrics is about 2.5 fl oz per pound of body weight per day, usually not more than 32 oz in 24 hours. A 10 lb baby would take about 25 oz a day. Babies vary, so follow hunger cues and your pediatrician's advice.

Is it safe to use tap water?

Use water from a safe source and follow the label. If you are unsure whether local tap or well water is safe, contact your local health department. CDC recommends extra precautions for infants under 2 months, born prematurely, or with weakened immune systems.

How long can prepared formula sit out?

Use prepared formula within 2 hours, and within 1 hour once feeding starts; throw away what the baby does not finish. Refrigerate formula you make ahead and use it within 24 hours.

Formula Mixing Calculator

Enter the water you will measure and pick the ratio printed on your formula tin to get the number of level scoops, with a bottle chart from 1 to 8 oz. Most US powders use 1 scoop per 2 fl oz of water and most UK and European powders 1 scoop per 30 mL. Always follow your label and your pediatrician.

Formula Settings

Unit

Water to Measure Before Powder (fl oz)

Ratio Printed on Your Container

Scoop Weight (grams, optional)

Find this on your formula can label. Used to show grams of powder.

Scaled Label Amounts

Enter your settings and tap Calculate.

Bottle chart for this ratio

Water first	Level scoops	Powder

How much per day? (guide)

About 2.5 fl oz (75 mL) of formula per pound of body weight a day, usually not more than 32 oz (960 mL), per the American Academy of Pediatrics. Babies vary: feed to hunger cues.

Baby's weight

Safety Reminders

Always add water to the bottle before the powder.
Use a level, unpacked scoop — never heaping.
Use within 2 hours of preparation and within 1 hour after feeding begins; refrigerate unused formula immediately and use within 24 hours.
Consult your pediatrician before changing the ratio.
Never add extra water to make formula last longer: watered-down formula can cause dangerously low sodium and seizures. If formula is hard to afford, ask your pediatrician or WIC office.

Prepared volume may exceed measured water because powder adds volume. This scales label arithmetic; it does not target final prepared volume or calculate calories.

CDC preparation and storage guidance

Formula scoops by bottle size

Level, unpacked scoops with the scoop from your own tin. Check that your label uses one of these ratios; if it does not, use the custom option above.

Water	1 scoop per 2 fl oz (60 mL)	1 scoop per 1 fl oz (30 mL)
1 fl oz (30 mL)	0.5 — not a whole scoop	1 scoop
2 fl oz (60 mL)	1 scoop	2 scoops
3 fl oz (90 mL)	1.5 — not a whole scoop	3 scoops
4 fl oz (120 mL)	2 scoops	4 scoops
5 fl oz (150 mL)	2.5 — not a whole scoop	5 scoops
6 fl oz (180 mL)	3 scoops	6 scoops
7 fl oz (210 mL)	3.5 — not a whole scoop	7 scoops
8 fl oz (240 mL)	4 scoops	8 scoops

Quick answer

Most US powdered infant formulas use 1 level, unpacked scoop per 2 fl oz (60 mL) of water, so 4 oz of water takes 2 scoops and 6 oz takes 3 scoops; most UK and European powders use 1 scoop per 30 mL (1 fl oz). Scoops = water ÷ water per scoop on your label. Use the scoop that came with the tin, add water first, and never add extra water to stretch formula.

Examples

Water	1 scoop per 2 fl oz (most US)	1 scoop per 30 mL (most UK/EU)
2 fl oz (60 mL)	1 scoop	2 scoops
4 fl oz (120 mL)	2 scoops	4 scoops
6 fl oz (180 mL)	3 scoops	6 scoops
8 fl oz (240 mL)	4 scoops	8 scoops
3 fl oz (90 mL)	1.5 — not whole	3 scoops

Enter your water amount and the ratio on your tin to get the scoops, grams and a bottle chart.

Summary

Powdered infant formula is made by adding a set number of level scoops to a set volume of water, and the ratio is printed on every tin. Most US powders, including Similac and Enfamil, use 1 unpacked level scoop per 2 fl oz (60 mL) of water; most UK and European powders use 1 scoop per 30 mL. Scoop sizes differ between products and even between country versions of the same brand, so the label on your tin always wins. This calculator scales that label ratio to the water you measure, flags amounts that do not come to a whole scoop, shows grams if your label lists a scoop weight, and prints a bottle chart. A daily amount guide uses the American Academy of Pediatrics rule of thumb of about 2.5 fl oz of formula per pound of body weight per day, up to 32 oz. It does not replace the instructions on the tin or advice from your pediatrician.

How it works

Choose fluid ounces or millilitres.
Enter the amount of water you will measure into the bottle before adding powder.
Pick the ratio printed on your tin: 1 scoop per 2 fl oz (60 mL), 1 scoop per 1 fl oz (30 mL), or enter the exact label ratio.
Optionally enter the scoop weight in grams from the label to see total powder.
Read the scoops to add and the bottle chart; if the result is not a whole scoop, choose a water amount that is.
Optionally enter your baby's weight to see the usual daily total as a guide.

Use cases

Finding how many scoops go in a 2, 4, 6 or 8 oz bottle.
Making a larger batch for the day with the same label ratio.
Converting a UK or European tin's 30 mL ratio to fluid ounces.
Teaching a partner, grandparent or babysitter the right scoop count.
Checking that a planned bottle size comes to a whole number of scoops.
Estimating roughly how much formula a baby takes per day by weight.

Frequently Asked Questions

Last updated: 2026-10-10 · Reviewed by Nham Vu