Anything with a TSA tag has a rule attached. Liquids, power banks, razors and scissors are the four that get pulled at the checkpoint most often. Tap the tag to see the rule before you pack it, not after.
How the quantities are worked out
Nothing here is a guess dressed up as a number. Every count comes from a rule you can see and argue with:
- Underwear =
days + 2, capped at 14. - Socks =
days + 2, capped at 12. - Tops and t-shirts =
days + 2, capped at 10. - Pants, jeans and shorts =
days / 3, rounded up, + 1, capped at 5. - Sleepwear =
days / 4, rounded up, capped at 3. - Swimwear = 2 once the trip is 4 days or longer, so one can dry.
- Diapers =
days x 6, capped at 60, plus a day's worth in the day bag.
The caps are the important part. Past about eight days the caps take over, because at that length you are doing laundry once whether you planned to or not, and packing fourteen shirts for a two-week trip is exactly how a bag ends up over the weight limit. If your trip is different, change any number after the list is built: the counts are only a starting point, and you can delete anything you will not use.
The weather setting swaps whole blocks of clothing rather than nudging counts, and mixed deliberately gives you both a rain layer and a warm layer, since that is the case where people underpack.
What each trip type adds
| Trip type | What it adds that nothing else does |
|---|
Swipe the table sideways to see every column.
Before you zip the bag
Questions people ask while packing
Will my list still be here tomorrow?
Yes, on the same device and the same browser. The list, every box you have ticked, everything you added and everything you deleted are stored locally in your browser, and they come back when you reopen the page. Nothing is sent anywhere and there is no account.
Two things clear it: using a private or incognito window, and clearing your browsing data. If your browser blocks local storage entirely the list still works perfectly for the session, it just will not survive a reload.
Why does the count stop going up on a long trip?
Because at some point you do laundry. Underwear caps at 14, tops at 10, pants at 5. For a three-week trip the honest answer is a week of clothes plus a plan for washing them, not three weeks of clothes and an overweight bag.
If you genuinely are not doing laundry, add the extras yourself with the add-an-item box. The counts are a starting point, not a verdict.
Which items on this list have TSA rules?
The ones carrying a TSA tag. The four that account for most checkpoint problems are liquids over 3.4 oz, power banks and spare lithium batteries, razors, and scissors. Tap any tag and it opens the rule for that exact item.
Power banks are the one that changed most recently: since 27 March 2026 they are carry-on only, limited to two spares per passenger, must stay within reach at your seat rather than in the overhead bin, and cannot be used to charge anything in flight. That is an airline and ICAO rule rather than a TSA rule, which is why the TSA website does not answer it.
Should I pack for the weather at home or at my destination?
Your destination, with one exception: the clothes you travel in. A December flight out of Chicago to Cancun means a coat you will carry for a week, so wear the coat, pack the shorts, and pick the destination weather here.
If the two ends of the trip are genuinely different, or the forecast is unsettled, choose mixed. It deliberately packs both a rain layer and a warm layer instead of splitting the difference, because underpacking a layer is the mistake that actually costs you a day.
What is the single most forgotten item?
Chargers, and specifically the cable rather than the plug. After that: a spare pair of glasses, an adapter for the country you are going to rather than the one you last visited, and any medication that lives in a bathroom cabinet rather than a bag.
The habit that fixes all of it is packing the day bag last and putting the four irreplaceables in it: medication, documents, chargers and anything with a lithium battery. Those are also the four things that must not go in a checked bag.
How far ahead should I start packing?
Build the list a week out and leave it open. The value is not in the packing session, it is in the days beforehand when you remember the thing you needed to buy, refill or charge. That is also when a prescription refill or a passport photo is still fixable.
Do the actual packing the night before, not the morning of. Bags packed in a hurry are the ones that end up over the airline's weight limit with a full-size shampoo bottle at the bottom.
Can I get this list onto paper?
You can print it, and the print version strips out everything except the list itself with empty boxes to tick. But the on-screen version is the one to use: it remembers what you have packed, it scales the counts to your trip, and it links the items that have rules attached.
Copy list is usually more useful than printing. It puts the whole thing on your clipboard as plain text, ready to paste into notes, a message to whoever you are traveling with, or a shared list.
Does the list know what fits in my bag?
No, and no packing list can. What it does is keep the counts realistic so you are not defeated before you start. For the size question, use the carry-on size checker: enter your bag's measurements and it tells you which of 36 airlines it fits as a carry-on and which it fails.
The order that works: build the list, check the bag size, then check anything with a TSA tag on it.