How much shampoo you need for a week away depends on how often you wash and how long your hair is, so the honest answer is counted in washes, not millilitres. Seven nights of washing daily is seven washes; every other day is four. To turn that into an amount, measure what you actually use at home for a week, then scale it to your trip. If you pack a bar instead of a bottle, most people get somewhere between 30 and 60 washes, depending on use and storage, which covers a normal week comfortably.
This guide is part of our travel toiletries checklist, which covers the rest of the wash bag.
- 1. Why is there no single answer for how much shampoo to pack?
- 2. How do you measure how much shampoo you use?
- 3. How many washes is your trip?
- 4. Will a 100 ml bottle last a week?
- 5. How do you decant shampoo for a trip?
- 6. How does a shampoo bar change the maths?
- 7. What if you share, have long hair or train every day?
- 8. Summary
- 9. Frequently asked questions
- 10. Sources
Why is there no single answer for how much shampoo to pack?
Because two things vary hugely from person to person: how often you wash, and how much hair you have.
You'll find packing guides online quoting a set number of millilitres per wash. We couldn't find a credible source behind those figures, so we won't give you one.
How do you measure how much shampoo you use?
Use one marked bottle for a week at home and see what's gone.
- Fill a 100 ml travel bottle (most have a scale on the side) with your usual shampoo.
- Use only that bottle for seven days, washing as often as you normally would.
- Note how many times you washed and how much is left.
- Divide what you used by the number of washes. That's your amount per wash.
- Multiply by the number of washes on your trip, and add a little extra for a sweaty day or a swim.
Do the same for conditioner if you use one.
How many washes is your trip?
Count washes, not nights. Here is the arithmetic for common trip lengths, rounded up so you never run short. The last column shows what happens when two people share one product and both wash daily.
| Trip length | Washing daily | Every other day | Twice a week | Two people, both daily |
|---|---|---|---|---|
| Weekend (2 nights) | 2 washes | 1 wash | 1 wash | 4 washes |
| 4 nights | 4 washes | 2 washes | 2 washes | 8 washes |
| 7 nights | 7 washes | 4 washes | 2 washes | 14 washes |
| 10 nights | 10 washes | 5 washes | 3 washes | 20 washes |
| 14 nights | 14 washes | 7 washes | 4 washes | 28 washes |
Multiply the washes by your measured amount per wash and you have your answer.
Will a 100 ml bottle last a week?
It depends on your measured amount per wash, but for carry-on, 100 ml is your ceiling per container, so it has to. Amsterdam Schiphol still limits liquids in hand luggage to containers of 100 ml at most, in one resealable, transparent 1-litre bag. Some airports with newer scanners allow larger containers, but the airport you fly home from may not. Assume 100 ml and pack for 100 ml.
If your weekly use is over 100 ml, you have three options: two bottles (which eats into the one-litre bag), buying shampoo when you land, or a solid bar, which isn't a liquid at all. The full rules by airport are in can you take soap on a plane.
Shampoo, body and face wash, all in one bar. Keep your hair and skin healthy on the go. Monoï-infused scent with a touch of vanilla. Designed for those always on the go.
How do you decant shampoo for a trip?
Use a clean, dry, soft travel bottle, fill it no more than about three-quarters, squeeze out the air and close it properly. The gap at the top gives the liquid room when pressure changes in the hold or cabin, which is when bottles tend to leak.
- Label each bottle. Shampoo and conditioner look the same in a clear tube.
- Keep liquids together in one sealed bag, away from clothes.
More fixes in how to pack toiletries so they don't leak. And travel-size bottles vs solid bars compares both honestly. Don't count on the hotel to top you up either: single-use toiletry packaging in EU accommodation is being phased out, as we explain in the EU hotel mini toiletries ban.
How does a shampoo bar change the maths?
A bar takes the measuring out of it: most people get somewhere between 30 and 60 washes, depending on use and storage, so one bar covers a week or two with room left over. The range is wide because it depends on your hair, how hard you rub the bar, and above all whether it dries out between washes.
There's one catch with a 3-in-1 bar. Because it also does body and face, every shower draws from the same bar, not only the days you wash your hair. So count every shower in your washes, not just hair washes. It's still one item doing three jobs. Our guide on using a shampoo bar on body and face explains how that works.
Storage matters more than anything else. A bar left wet goes soft and wears down faster. A ventilated tin or mesh pouch, not a sealed plastic bag, keeps it going. See how long a shampoo bar lasts and how to travel with a shampoo bar for the details.
Shampoo, body and face wash, all in one bar. Cooling, refreshing and designed for those always on the go.
What if you share, have long hair or train every day?
Sharing doubles the washes, long hair raises the amount per wash, and training can push you to wash daily. Measure for the real routine, not the ideal one.
Sharing with a partner
Use the "two people" column in the table, or add both of your measured weekly amounts together. With a bar, you're both drawing from the 30 to 60 range, so a longer trip for two may need a second bar.
Long or thick hair
Your amount per wash is higher, which is exactly why a generic figure is useless. Measure at home.
Sweaty activities and daily training
Hiking, surfing or a hotel gym can turn a twice-a-week routine into a daily one. We look at how often to wash when you're active in washing your hair when you train every day. If you're camping or on the move for weeks, wash only where the water goes into a drain, like a shower, sink, or campsite wash block; backpacking toiletries covers longer trips.
Shampoo, body and face wash, all in one bar. Keep your hair and skin healthy on the go. Monoï-infused scent with a touch of vanilla. Designed for those always on the go.
Summary
For a week away, count how many times you'll wash, measure what you use per wash at home, and multiply.
For carry-on, 100 ml per container is the limit to plan for. A bar skips the maths: most people get somewhere between 30 and 60 washes, depending on use and storage, but with a 3-in-1 remember to count every shower, not just hair days.
Frequently asked questions
How much shampoo do I need for 7 days?
Seven days is seven washes if you wash daily, four if you wash every other day. Measure how much you use per wash at home and multiply.
Is 100 ml of shampoo enough for a week?
For many routines it may be, but the only way to know is to measure your own use for a week at home. If you use more, pack a second bottle in your liquids bag, buy shampoo on arrival, or switch to a bar.
How many washes do you get from a shampoo bar?
Most people get somewhere between 30 and 60 washes, depending on use and storage. Keeping the bar dry between washes makes the biggest difference. More in our guide on how long a shampoo bar lasts.
Can two people share one shampoo bar on holiday?
Yes, as long as you're both happy with the same bar and scent. Double the number of washes when you plan, and let the bar dry between showers.
Do I need to pack conditioner as well?
Only if you use it at home, and measure it the same way as shampoo. Whether you need one with a bar depends on your hair, which we cover in do you need conditioner with a shampoo bar.
Should I just buy shampoo when I arrive?
For a longer stay it can make sense, but you'll likely end up with a full-size bottle you can't take home in hand luggage. For a week, packing a measured amount or a bar is usually simpler, and the rest of the wash bag is in our travel toiletries checklist.
Sources
The facts in this article are based on the sources below, checked in September 2026.
- Liquids in hand baggage. Amsterdam Airport Schiphol, 2026.
