How Much Formula Do Twins Need? The Daily Math
Work it out for each twin separately. The AAP’s rule of thumb is about 2½ ounces of formula per pound of body weight per day, and no more than about 32 ounces a day for any one baby. So twins weighing 8 and 10 pounds need roughly 20 and 25 ounces, about 45 ounces a day between them. That is around 12 to 16 bottles a day in the early months, and roughly a large tub of powder every three days. Twins born early, or on a fortifier or a NICU feeding plan, follow their pediatrician’s numbers instead of any rule of thumb.
The per-baby numbers
Everything here comes from the AAP’s page on amount and schedule of formula feedings:
- First week: “no more than about 1 to 2 ounces (30 to 60 ml) per feed.”
- By the end of the first month: at least 3 to 4 ounces per feed, “about every 3 to 4 hours.”
- By 6 months: 6 to 8 ounces “at each of 4 or 5 feedings in 24 hours.”
- The weight rule: “about 2½ ounces (75 mL) of infant formula a day for every pound (453 g) of body weight,” with an upper limit of “about 32 ounces (960 mL) of formula in 24 hours.”
The AAP also says babies “regulate their intake from day to day,” so the rule gives you a ballpark, not a target to hit at every feed. If either twin keeps wanting a lot more or a lot less, that is a question for the pediatrician. Betteroo’s month-by-month table of bottle sizes lays out the same AAP ranges by age, if you want them in one grid.
Why one number for “the twins” goes wrong
Twins are often different sizes, sometimes by a pound or more, and the weight rule makes that matter. Use each baby’s own weight:
| Twin | Weight | About 2.5 oz per lb | Per-baby ceiling |
|---|---|---|---|
| A | 10 lb | 25 oz a day | 32 oz |
| B | 8 lb | 20 oz a day | 32 oz |
| Together | about 45 oz a day | 64 oz |
If you make up bottles as if both were the bigger twin, the smaller one is offered more than they need and you throw out the rest. Make up both as if they were the smaller twin and the bigger one comes up short. A per-baby column in the A|B feeding and sleep log is what shows the difference after a few days.
Preterm twins are a separate case. Babies who came home from the NICU are often on a set volume, a higher-calorie formula or a fortifier, and the pediatrician sets those amounts. Don’t apply the 2.5-ounce rule over the top of that plan.
Bottles per day
At a feed every 3 to 4 hours, each baby takes about 6 to 8 bottles a day in the early months, so twins come to about 12 to 16 bottles a day. By around 6 months, at 4 or 5 feeds each, that drops to 8 to 10.
That count is your washing load as well as your feeding load. Plan the bottle stock around it: enough clean bottles for a full day, all from one system so the parts are interchangeable. Feeding twins, every method compared covers how families split that work.
Tubs per week, and what it costs
How long a tub lasts depends on its yield, which is printed on the container. One example, as listed on enfamil.com in October 2026: the Enfamil NeuroPro 20.7 oz tub “makes approximately 33 four-ounce bottles”, about 132 ounces of made-up formula, at a list price of $42.99.
| Twins drinking | Days per tub | Tubs per week | Tubs per 30 days | Cost per 30 days at that price |
|---|---|---|---|---|
| 45 oz a day (the example above) | about 3 | about 2½ | about 10 | roughly $440 |
| 64 oz a day (both at the ceiling) | about 2 | about 3½ | about 15 | roughly $620 |
Treat those totals as a worked example, not a quote. Prices change, other brands and sizes cost different amounts, and buying by the case or a store brand usually costs less per ounce. Do the same arithmetic with the yield and price of whatever formula your pediatrician has you on. Combo feeding lowers all of it, and combo feeding twins covers how families decide which feeds become formula.
Never stretch formula with extra water to make it last. The AAP’s page on preparing formula with water warns that diluted formula can cause “serious health and development problems,” including water intoxication. If the cost is a problem, it says to check with your pediatrician, local health department, food pantry or social service agency. WIC is the other place to ask.
Making up 12 to 16 bottles without losing the day
- Batch for the next 24 hours, not the week. The AAP says prepared formula that has not been fed “may be stored in the refrigerator for 24 hours.” A Dr. Brown’s formula mixing pitcher makes up a day’s worth in one go. Pour each bottle as it is needed.
- Throw out what is left after a feed. Prepared formula “must be discarded within 1 hour after feeding it from the bottle.” With twins, never pass one twin’s unfinished bottle to the other.
- Boiled water for the youngest and smallest. The AAP says to use boiled water, cooled for about 5 minutes, for babies under 2 months, babies born prematurely, and babies with a weakened immune system. That covers a lot of twin pairs.
- Pre-measure for outings. A two-pack of Munchkin three-compartment formula dispensers gives each twin their own, with measured powder for three bottles each. Add it to water at feed time.
- Never prop a bottle. Feeding two at once is a skill, and bottle-feeding twins alone has the setups that keep both babies held or supervised for the whole feed. A propped bottle is never one of them.
FAQ: formula amounts for twins
How many ounces of formula do twins drink a day?
Each twin needs roughly 2½ ounces per pound of body weight per day, up to about 32 ounces. Two 9-pound babies would take around 22 ounces each, about 45 together. By the time both are near the 32-ounce limit, the pair is drinking around 64 ounces a day.
Should both twins get the same size bottle?
Not unless they weigh about the same and feed about the same. Make up each baby’s bottle for that baby and log what each one drinks. Twins can differ by an ounce or more per feed.
How many cans of formula do twins go through?
It depends on the container’s yield. In the example above, a tub that makes about 132 ounces lasts twins about 2 to 3 days, so roughly 10 to 15 tubs a month on formula alone. Check the “makes approximately” line on your own container and divide.
