How much formula does a baby need per day?

About 2.5 ounces per pound of body weight per day, according to the AAP, and usually no more than about 32 ounces. A 10 lb baby needs roughly 25 ounces a day.

How long does a can of formula last?

It depends on your baby's intake and the scoop size. A baby drinking 24-30 oz a day typically gets through an 800 g tub in about 5 to 8 days. Use the calculator with your tin's numbers.

How many scoops of formula per day?

Divide the daily amount by the water per scoop on your tin. With 1 scoop per 2 oz, a baby drinking 24 oz a day needs 12 scoops.

Can I add an extra scoop to make my baby fuller?

No. Always mix formula exactly as the instructions say. Extra powder can cause dehydration and constipation, and too little can mean your baby doesn't get enough nutrients.

Do I need to buy formula if I'm breastfeeding?

Not usually. Talk to your pediatrician or a lactation consultant if you're thinking of supplementing, because it affects milk supply.

Formula Calculator: Daily Amount & Tub Use / Tot

Medically reviewed by Safi Ullah Khan · Written by Muneeb Rana · Last updated 21 October 2026

Quick answer: A formula calculator estimates how much prepared formula your baby needs per day and how fast you'll use a tub. Daily need is about 2.5 oz per pound of body weight, up to 32 oz (AAP). Then use the scoop-to-water ratio printed on your tin to convert that into scoops and tubs.

TL;DR

Daily need: about 2.5 oz per lb (165 ml per kg), rarely over 32 oz.
Always mix exactly as the tin says; never add extra water or powder.
The tool shows scoops per day and days per tub for budgeting.

This formula calculator does two jobs: it estimates how much prepared formula your baby drinks in a day, and it turns that into scoops, grams and tubs so you can plan purchases. It doesn't change how you mix formula. Brands differ, so it uses the scoop ratio you copy from your own tin.

How to use the formula calculator

Enter your baby's weight and age (or use the daily amount from your log).
Copy the mixing ratio from your tin, for example 1 scoop per 2 fl oz (60 ml) of water, and the scoop weight in grams if listed.
Enter the tub size in grams (or ounces).
Read prepared formula per day, scoops per day, days per tub and tubs per month.
Round up when you shop so you never run short.

How the formula calculator works

daily_oz       = min(weight_lb * 2.5, 32)     # or the real daily total from your log
scoops_per_day = daily_oz / water_oz_per_scoop
grams_per_day  = scoops_per_day * scoop_grams
days_per_tub   = tub_grams / grams_per_day
tubs_per_month = 30.4 / days_per_tub

The tool never suggests changing the ratio. The NHS and CDC both warn that adding too much or too little powder can make your baby ill, so always follow the manufacturer's instructions.

Worked example

Ava weighs 11 lb, so she needs about 27.5 oz a day. Her tin says 1 scoop (8.7 g) per 2 fl oz of water: 27.5 ÷ 2 = about 14 scoops a day, or 120 g. An 800 g tub lasts about 6.5 days, so her family needs roughly 4.7 tubs a month.

Safe preparation basics

Wash your hands and bottles, use the water and temperature your tin specifies, add water first and then level scoops, and use prepared formula within the time on the label. The NHS advises making each feed fresh. Never microwave bottles, because hot spots can scald.

Switching formula or brands

Different formulas use different scoop sizes, so re-enter the ratio whenever you switch. Talk to your pediatrician before switching to a specialty formula, and see our formula and feeding guides for amounts by month.

Track real bottles instead of guessing

If you log bottles in Tot's baby feeding tracker, you can use your baby's actual average daily total here, which is more accurate than the weight rule. Feeding insights show the average per bottle.

Download Tot free on the App Store or Google Play. Free with ads; optional Premium.

Sources

AAP HealthyChildren.org: Amount and Schedule of Baby Formula Feedings: www.healthychildren.org (accessed 21 October 2026)
CDC: How Much and How Often to Feed Infant Formula: www.cdc.gov (accessed 21 October 2026)
NHS: Formula milk, common questions: www.nhs.uk (accessed 21 October 2026)
AAP HealthyChildren.org: How Often and How Much Should Your Baby Eat?: www.healthychildren.org (accessed 21 October 2026)

Medical disclaimer:

Tot and this website give general information only. Feeding, sleep and growth ranges vary; always follow your pediatrician's advice. If your baby is unwell, contact your doctor or emergency services.

Baby Formula Calculator