Going back to work while you're still breastfeeding brings up a lot of questions, and the one we hear most is: how much breast milk do I actually need? Scroll through social media and you'll see freezers packed wall to wall with milk bags, which can make you feel behind before you've even started.

The good news is that most mums need far less than they think. This guide covers how to work out your number, when to start building a stash, how to store it safely using Australian guidelines, and what to do when your freezer can't fit one more bag.

How much breast milk do you need before going back to work?

You don't need months of milk saved. The Australian Breastfeeding Association points out that the milk you express one day is often enough for the next, so a huge frozen stash usually isn't necessary. What you need is enough to cover the feeds you'll miss, plus a small buffer.

Here's a simple way to work out your number:

1. Count the feeds you'll miss. If you're away from 8am to 5pm and your baby feeds roughly every three hours, that's about three feeds.
2. Work out a typical feed. Note how much your baby takes in a bottle over a few days. For breastfed babies, intake tends to level out between about one and six months, so bottle sizes don't keep climbing the way they do with formula.
3. Multiply it out. Three feeds of around 100ml is roughly 300ml per work day.
4. Add a buffer. A few extra days of milk covers a missed pumping session, a growth spurt or a day your supply dips.

If you're pumping at work, the milk you express today becomes tomorrow's bottles, and your buffer stays in the freezer for backup.

When should you start building a breast milk stash?

Starting a few weeks before you return to work gives you time to build a reserve without pressure. Many mums add one extra pumping session a day, often in the morning when supply tends to be higher. Even small amounts add up: 20ml a day over a few weeks becomes several bottles.

Use the same weeks to get your baby used to a bottle or cup from another carer, so the first day of childcare isn't the first time they've had one.

How to store breast milk safely (Australian guidelines)

These are the storage times recommended by the Australian Breastfeeding Association for freshly expressed milk:

Milk that's been thawed in the fridge should be used within 24 hours, and thawed or warmed milk should never be refrozen. For the full breakdown, read our guide to breast milk storage guidelines in Australia.

Tips for sending breast milk to childcare

• Store in small portions. 50 to 100ml bags or bottles mean less waste, as carers can warm a little more if your baby is still hungry.
• Label everything. Write your baby's name and the date you expressed on every bag or bottle.
• Keep it cold on the way. Use an insulated bag with a freezer brick and ask the centre to put it straight in the fridge or freezer.
• Check the centre's policy. Every childcare centre handles breast milk a little differently, so ask how they want it packed, labelled and stored.
• Do a smell test early. If your thawed milk smells or tastes soapy, you may have high lipase milk. It's safe, but some babies refuse it, so it's better to find out before you've frozen weeks of it.

If your baby is fussy about thawed milk, these tips for babies who won't drink frozen breast milk can help.

Pumping at work: your rights in Australia

Under the federal Sex Discrimination Act, it's unlawful to discriminate against someone because they're breastfeeding, and employers are expected to make reasonable efforts to support you to express at work. That usually means time to pump and a clean, private space that isn't a bathroom.

Talk to your manager before your first day back. Ask about breaks, where you can express, and where you can store milk. Most mums need 15 to 30 minutes per session. Some awards and workplace agreements include paid lactation breaks, so it's worth checking yours. Raising Children Network has a good overview.

What to do when your freezer is full of breast milk

Here's the part nobody warns you about. Once you're pumping at work, many mums end up with more milk than their baby drinks. The freezer fills up, the oldest bags creep towards their use-by date, and every power outage feels like a disaster.

That's where freeze-drying comes in. At The Milk Fairy, we remove the water from your frozen milk at low temperatures to help protect its nutrients, fats and antibodies, and turn it into a shelf-stable powder that keeps for up to 3 years.

• Your milk is processed separately in our Pure Protect pouches and is never mixed with anyone else's.
• It comes home in labelled pouches with your personal rehydration ratio printed on every label.
• No freezer space, no thawing, no worrying about blackouts.
• Perfect as a backup for sick days, travel or the months after you stop pumping.

We post you an insulated kit with a GPS tracker, collect it from your door, and send your milk home as powder, Australia wide. Here's how to pack your milk, and how to rehydrate your powder when it's time for a feed.

Choose your freeze-drying kit

Frequently asked questions

How much breast milk should I have frozen before going back to work?

Enough to cover the feeds you'll miss on your first day or two, plus a few days of buffer. If you're pumping at work, what you express each day usually covers the next day's bottles.

How long does frozen breast milk last?

In Australia, the guidelines are 3 months in a freezer with its own door and 6 to 12 months in a deep freeze at -20°C. Freeze-dried breast milk keeps for up to 3 years on the shelf.

Can childcare use freeze-dried breast milk?

Absolutely! Freeze-dried milk is rehydrated with water using the ratio on your label, so it's simple for carers to prepare.

Do I have to pump at work to keep breastfeeding?

Not always. Some mums pump at work, some breastfeed before and after work only, and some combine both. How often you need to express depends on your baby's age and your supply. A lactation consultant can help you make a plan that suits you.

Going back to work is a big change, and how you feed your baby through it is your call. Whether you pump every day or keep a small stash for backup, a little planning makes the transition so much easier.