Formula Feeding Guide: How to Choose, Prepare and Feed Your Baby Safely

Choosing to formula feed your baby is a loving, responsible decision. Full stop. Whether you are mix feeding or using infant formula from day one, your baby needs food and you deserve support, not side‑eye. This guide walks you through how to choose baby formula, how to prepare formula safely, how much to offer, and how to keep bottles clean without losing your mind at 3 a.m. Fed is best, and formula is a valid choice.

Types of baby formula and how to choose

Standing in front of a wall of tins can feel like a pop quiz. Here’s a calm, plain‑English tour. Speak with your GP, midwife, health visitor or paediatrician if you are unsure which infant formula is right for your baby.

Cow’s milk based formula

• Most babies in the UK start on a standard cow’s milk based first milk.
• It is designed to be as close as possible to breast milk in protein, fat and carbohydrate profile.
• Comes as powder or ready‑to‑feed liquid. Powder is cheaper, liquid is convenient.

Who it suits: The majority of healthy, full‑term babies.

Hypoallergenic baby formula

• Extensively hydrolysed or amino acid based formulas where proteins are broken down to reduce reactions.
• Used for diagnosed or suspected cow’s milk protein allergy.
• You should not switch to a hypoallergenic baby formula without advice. Always consult your GP or paediatrician first.

Who it suits: Babies with allergy symptoms such as blood in stools, persistent eczema with feeding issues, wheeze, or poor growth as assessed by a professional.

Anti‑reflux formula

• Thicker formulas designed to reduce regurgitation.
• Often need a faster flow teat so baby is not working too hard to drink.
• Reflux can be normal in young babies. Anti‑reflux formulas are one option, but it is wise to discuss with your health visitor or GP before changing.

Who it suits: Babies with troublesome spit‑up who are otherwise thriving, when advised.

Other options you might hear about

• Lactose‑free formula: for rare lactose intolerance diagnosed by a clinician.
• Soya formula: not usually recommended for babies under 6 months in the UK unless advised by a specialist.
• Goat’s milk formula: nutritionally similar to cow’s milk based options, but not suitable for cow’s milk protein allergy.
• Comfort or “colic” formulas: slightly altered proteins or lactose levels. Evidence is mixed. If you are considering these for wind or colic, check in with your health visitor first.

A quick word on “the best formula for newborn”: it is the one your baby tolerates, that meets UK infant formula standards, and that you can prepare safely and affordably. Labels and marketing are loud. Your baby’s cues are louder.

How much formula per feeding and how often to feed a newborn

Newborn tummies are tiny. They grow fast. Think small, frequent feeds at first, then gradually larger volumes with slightly longer gaps.

Here is a simple guide. It is a guide, not a rulebook. If your baby was premature, has jaundice, or your midwife has given you a plan, follow that plan.

• Day 1: 5 to 15 ml per feed, about 8 to 12 feeds in 24 hours.
• Days 2 to 3: 15 to 30 ml per feed, still every 2 to 3 hours.
• Days 4 to 7: 30 to 60 ml per feed, moving towards 60 to 90 ml by the end of week 1.
• Weeks 2 to 4: 60 to 90 ml per feed, roughly 6 to 8 feeds if taking larger volumes, otherwise more frequent smaller feeds.

Another way to think about it: after the first week, many babies need around 150 ml per kg of body weight per day, split across feeds. Some need up to 200 ml per kg. For example, a 3.5 kg baby might take around 525 ml to 700 ml in 24 hours, spread out. Appetite varies with growth spurts, naps, and just… baby life.

How often to feed a newborn

• Aim for every 2 to 3 hours in the early weeks. That often means 8 to 12 feeds in 24 hours.
• Wake a very sleepy baby for feeds at least every 3 hours in the first couple of weeks unless your midwife or GP says otherwise.
• Look for early hunger cues: stirring, mouth opening, lip smacking, rooting. Crying is a late sign.
• Do not force a finish. If baby turns away, relaxes their hands, or falls asleep, they may be done.

If you are building a formula feeding schedule, try flexible rhythms rather than fixed timetables. Babies are not clocks. Patterns do emerge. But your baby did not read the manual.

How to prepare formula safely, step by step

Powdered infant formula is not sterile. Preparing it correctly matters. The NHS advises making up each feed fresh using water hot enough to kill bacteria.

What you need

• Kettle
• Fresh cold tap water
• Sterilised bottles and teats
• Formula tin and scoop that comes with it
• A safe work surface and clean hands

How to make formula

1. Wash your hands. Clean and dry the worktop.
2. Boil fresh tap water in the kettle. Do not use bottled water for routine feeds.
3. Leave the boiled water to cool in the kettle for no more than 30 minutes. You want it at least 70°C.
4. Pour the required amount of hot water into your sterilised bottle.
5. Add the exact number of level scoops as directed on the tin. Use the scoop provided. Level it with the leveller or a clean, dry knife. Do not pack the powder.
6. Put the teat and cap on. Shake gently until the powder fully dissolves.
7. Cool the bottle under a running cold tap or in a jug of cold water. Swirl occasionally. Test on the inside of your wrist. It should feel warm, not hot.
8. Feed your baby. Hold your baby close, keep the bottle at an angle to fill the teat, and allow little pauses so they can breathe and rest.

Key safety points

• Prepare formula safely by using water at least 70°C, measuring precisely, and using bottles that have been sterilised.
• Do not microwave bottles. Hot spots can burn.
• Do not reheat formula. Bacteria multiply quickly in made‑up feeds.
• If not used immediately, cool the made‑up feed quickly and use within 2 hours at room temperature. If you must store, place it in the back of the fridge right away and use within 24 hours.
• Once your baby starts a feed, use it within 1 hour, then throw away any leftover milk.
• Clean and dry the formula scoop. Store it inside the tin, not buried in the powder.

Night feeds and going out

• For night feeds, you can boil water, let it cool for no more than 30 minutes, pour the right amount into sterilised bottles, then keep the water in a clean, closed container and use within 24 hours. Re‑boil and cool if unsure the water stayed hot enough. Or keep a vacuum flask of recently boiled water that maintains at least 70°C, plus a separate container of cooled boiled water to adjust temperature after mixing.
• Ready‑to‑feed liquid formula is a handy option for nights or travel. It is sterile before opening.

If your baby is under 2 months, was premature, or has a weakened immune system, extra care with hygiene and water temperature is especially important. When in doubt, ring your health visitor or GP surgery for advice.

Bottle hygiene: sterilising, cleaning and storage

Newborns do not have fully developed immune systems. Keeping feeding equipment clean is part of keeping them well. If you have been frantically Googling “how to sterilize baby bottles”, here is the calm version.

Cleaning after every feed

• Rinse the bottle, ring, and teat in cool water as soon as possible.
• Use a bottle brush and hot soapy water to scrub each part thoroughly, including the teat hole. Squeeze water through the teat.
• Rinse in clean water.

Sterilising methods

• Steam steriliser: electric or microwave units. Follow the manufacturer’s instructions. Keep the lid closed so everything stays sterile inside.
• Boiling: submerge all parts in a large pan of water for at least 10 minutes. Make sure there are no air bubbles trapped. Allow to cool before use.
• Cold water sterilising solution: use a clean container and sterilising tablets or liquid. Change the solution every 24 hours. Submerge all items fully.

Storage

• If you assemble the bottle right after sterilising, it can stay sterile for up to 24 hours in the steriliser with the lid closed. If you remove parts, assemble while they are still wet from sterilising and keep them covered.
• Avoid air‑drying on a rack where dust settles. Go straight from steriliser to assembly if you can.

When to replace bottle nipples

• Check teats every day. If they are sticky, cracked, swollen, thinning, discoloured, or the hole has stretched, replace them.
• Many parents replace silicone teats every 2 to 3 months, earlier if there are signs of wear.
• If feeds suddenly take forever, your baby is collapsing the teat, or gets frustrated, consider moving up a flow size. If milk pours out when you tip the bottle upside down, it is too fast.

Signs your baby is tolerating formula well

Babies tell us a lot without words. Signs that a new formula is suiting your baby:

• Content between feeds most of the time, with the usual fussy patches
• Steady weight gain along their centile line as checked by your health visitor
• 6 or more wet nappies a day after the first week, pale urine, and regular soft stools
• Mild wind or small spit‑ups that do not upset them
• Skin looks normal for them, no new persistent rashes
• They feed comfortably and relax at the end

Signs of intolerance or allergy to watch for

Formula intolerance and cow’s milk protein allergy can look similar to normal newborn fussiness, which is why it helps to keep notes and get support. Call your GP or health visitor if you notice:

• Persistent vomiting after most feeds, not just small possets
• Diarrhoea, especially with mucus or blood
• Constipation with hard, painful stools over several days
• Widespread rash, hives, or worsening eczema that seems linked to feeds
• Wheeze, noisy breathing, or persistent cough with feeds
• Extreme irritability, back‑arching, pulling away from the bottle, or refusing most feeds
• Poor weight gain or weight loss

Get urgent help if you see any signs of a severe allergic reaction: swelling of the lips or face, difficulty breathing, floppy or very sleepy baby, or sudden paleness. In the UK, call 999.

If allergy is suspected, your GP may recommend a hypoallergenic baby formula trial and follow‑up. Do not change formulas repeatedly on your own. Too many changes can make it hard to see what is helping.

Gentle tips that make formula feeding easier

Little tweaks can transform your days.

• Paced bottle feeding: Hold your baby fairly upright, keep the bottle at a slight angle so the teat is just full, and offer pauses. It reduces gulping and can help with wind.
• Hold your baby close: Feeding is bonding. Eye contact, a soft voice, a cheek against your chest. It all counts.
• Write down what you make: A simple note on your phone of times and volumes helps you spot patterns and keeps different carers on the same page.
• Share the load: If a partner, grandparent, or friend offers a feed, brilliant. You are not the default machine for everything.
• Keep a small “feeding kit”: Tin, scoop, clean bottles, bottle brush, steriliser instructions on the fridge. When you are tired, fewer decisions feel like a gift.

Quick answers to common questions

• How to prepare formula? Use boiled water cooled for no more than 30 minutes so it is at least 70°C, add level scoops as per the tin, mix, cool, and feed. Do not reheat.
• How much formula does a newborn need? Start small. Around 30 to 60 ml per feed in the first few days, moving towards 60 to 90 ml by the end of week 1. Then roughly 150 ml per kg per day split across feeds, adjusting to your baby.
• How often to feed a newborn? Every 2 to 3 hours to begin with, including overnight.
• How to sterilize baby bottles? Steam, boil for 10 minutes, or use a cold water sterilising solution. Clean thoroughly first.
• When to replace bottle nipples? At the first sign of wear, or about every 2 to 3 months, and sooner if the flow is clearly wrong for your baby.

You are doing a big thing. Feeding a baby takes time, patience, and a fair bit of washing up. It also brings quiet moments that you will remember for years. If anyone makes you feel guilty for using infant formula, that is their stuff, not yours. Your baby needs you fed, rested where possible, and confident. The rest is just steps: choose a suitable baby formula with your clinician’s input if needed, prepare formula safely, follow your baby’s cues for how much and how often, keep the kit clean, and stay open to small adjustments.

One feed at a time. You’ve got this.