Return to work
How much breast milk do you need to stash before going back to work?
Scroll through pumping accounts and you will see freezers packed with hundreds of bags. It is easy to feel behind. The good news is that most mums going back to work do not need a huge stash. If you can express while you are at work, the milk you pump today covers tomorrow. Your freezer stash is a buffer for the odd short day, not a supply for months.
The short answer
Aim for about three to five working days of milk in the freezer. For many families that works out at roughly 1 to 2 litres. Work out your own figure with the steps below, because it depends on your baby's age, how long you are away and whether you can express at work.
Work out your daily number
- Count the hours you are away, including your commute. A 9 to 5 job with a 30-minute journey each way is 9 hours.
- Count the feeds you will miss. If your baby feeds about every 3 hours, 9 hours away means about 3 feeds.
- Estimate how much your baby takes per feed. Look at what they take from a bottle now. If they only breastfeed, a rough average of 90 to 120ml per feed is often quoted for babies between 1 and 6 months, but every baby is different.
- Multiply. 3 feeds × 100ml = about 300ml per working day.
Worked examples
| Situation | Missed feeds | Per working day | Suggested stash |
|---|---|---|---|
| Full time, baby 6 to 9 months, expressing at work | 3 × 100ml | About 300ml | 900 to 1,500ml |
| Part time, 3 days a week, expressing at work | 3 × 100ml | About 300ml | 600 to 900ml |
| Full time, baby 12 months or older on solids | 1 to 2 × 100ml | 100 to 200ml | 300 to 600ml |
| Full time, cannot express at work | 3 × 100ml | About 300ml | 300ml for every working day |
If you cannot express at work at all, your stash has to cover every working day, which adds up quickly. In that case it is worth talking to your employer about a short break and a private space, combining breastfeeding at home with formula during the day, or planning a gradual change. A health visitor or infant feeding team can help you plan.
Why UK mums often need less
In the UK you can take up to 52 weeks of Statutory Maternity Leave (see GOV.UK). Many mums go back when their baby is between 9 and 12 months old. By then, the NHS recommends babies have been eating solid foods alongside milk since around 6 months, so the amount of breast milk needed during the day is often lower than it was in the early weeks. US advice, written for mums returning after a few weeks, often assumes a much bigger stash.
When to start building your stash
Starting three to four weeks before your return date is usually plenty. One extra expressing session a day, often after the first morning feed when many mums have the most milk, adds up quickly. Even 60ml a day for 4 weeks gives you about 1.7 litres.
- Freeze in small portions of 60 to 120ml so you waste less. See how to freeze and label breast milk.
- Label every bag with the date and use the oldest first.
- NHS guidance says frozen breast milk keeps for up to 6 months at -18°C or colder. See our UK breast milk storage guide.
- Do a few practice days with a bottle and your childcare before your first day back.
Expressing at work in the UK
Tell your employer in writing that you are breastfeeding before you return. Employers must carry out a risk assessment and provide somewhere suitable for you to rest. Acas guidance on breastfeeding at work recommends a private, clean room (not a toilet) to express and a fridge to store milk. Many employers are happy to agree breaks once you ask.
Our free stash planner on the Little Stash homepage shows how a little extra each day adds up before your return date.
Common questions
How much breast milk should I have stored before going back to work?
Most mums who can express at work need around three to five working days of milk, often 1 to 2 litres. Work it out as the number of feeds you will miss each day multiplied by how much your baby takes per feed.
When should I start building a freezer stash?
Three to four weeks before you go back is usually enough. Adding one extra expressing session a day builds a stash steadily without exhausting you.
Do I have a right to express milk at work in the UK?
Employers must do a risk assessment and provide somewhere suitable for breastfeeding mothers to rest. Acas recommends a private room and a fridge for storing milk. Tell your employer in writing that you are breastfeeding before you return.
Sources: GOV.UK: Maternity pay and leave; Acas: Breastfeeding at work; NHS: Your baby's first solid foods; NHS: Expressing and storing breast milk.
This article is general information, not medical advice. Little Stash is independent and not affiliated with or endorsed by the NHS. If you are worried about your baby's feeding or your supply, speak to your midwife, health visitor or GP, or call the National Breastfeeding Helpline on 0300 100 0212.