Packing List Generator

How the list is built from days and laundry

A packing list is arithmetic, not taste. You need one outfit per day, a spare set of underwear and socks, one layer for the coldest hour of the day, and shoes that match what you will do. The only real variable is whether you can wash clothes on the trip, because one laundry stop resets the count back to zero.

The generator works from a wash cycle. With no laundry, the cycle is the whole trip, so a 14 day trip needs 14 tops. With laundry access, the cycle is 5 days, which is one small load in a hotel sink or a laundromat. Anything past day five reuses clothes you already packed, so a 14 day trip and a 7 day trip produce the same list.

Bottoms get a different rule because pants and shorts get worn more than once. The list takes half the tops, rounded up, with a floor of two pairs. Shoes are two pairs: one for walking and one for everything else. Layers depend on the weather, and the activity adds gear that does not count as clothing, like a headlamp or a rain shell.

The gap between the last two columns is the whole argument for doing laundry. Two weeks without a washer is 55 items, which is a large checked bag and a sore shoulder. The same two weeks with one wash is 24 items, which fits a carry-on.

Worked example: seven days with no laundry

Take a 7 day trip in mild weather, city walking, no laundry, checked bag allowed. The list comes out to 7 tops, 4 bottoms, 8 pairs of underwear, 8 pairs of socks, 2 pairs of shoes, 1 layer and 1 set of sleepwear. That is 31 items, and the clothing weighs about 13 lb.

Thirteen pounds of clothing sounds light, and it is. The bag itself adds 7 to 9 lb for a 24 inch roller, and toiletries, chargers, and a pair of shoes you wear on the plane add another 3 to 5 lb. The scale at check-in reads closer to 25 lb, which is well inside the 50 lb limit most US airlines allow on a checked bag.

Thirty-one items is also the point where a carry-on stops working without help. A 40 liter bag holds about 20 to 24 items once you count shoes and a toiletry kit, so the default 7 day list needs either a checked bag or a cut. The generator flags that in the bag line, and the trim below shows what to drop if you want to stay carry-on.

The weight estimate uses 0.4 lb per top, 0.9 lb per bottom, 0.1 lb each for underwear and socks, 1.5 lb per pair of shoes, 1.2 lb per layer, and 0.7 lb for sleepwear. It is a planning number, not a luggage scale. A heavy sweater or a pair of boots will beat it, and a week of thin t-shirts will come in under it.

What one laundry stop changes

One wash changes the list more than any other input. Set laundry to yes and the cycle drops to 5 days, which caps the tops at 5 and the bottoms at 3. A 14 day trip falls from 55 items to 24 items, and the packed weight drops from 20 lb to 11 lb.

That is a 31 item difference from a single load of laundry, which usually costs $3 to $6 in a hotel machine or $8 to $12 at a wash and fold. Per item, it is the cheapest packing decision on the page.

Two practical notes. First, a 5 day cycle assumes a real wash with soap and a dryer, not a rinse in the sink. A sink wash dries overnight only for thin synthetics and merino, so pack one extra top if you plan to rely on it. Second, laundry access changes the fabric choice as much as the count. Quick dry fabrics let you wash at day three and wear the same shirt on day five, while cotton takes a full day to dry and often still feels damp in a hotel bathroom.

If the trip has a washer but you would rather not spend an evening on it, the middle path is a 7 day cycle: pack 5 tops, 3 bottoms and 6 pairs of underwear, then hand wash the small items at day four. That lands at 24 items and covers a 10 day trip without a machine.

Carry-on only: the items to cut

Carry-on only is a hard constraint, and the trim is specific. On the 7 day list the generator cuts 8 items: tops drop from 7 to 5, bottoms from 4 to 3, underwear from 8 to 6, and socks from 8 to 5. The result is 23 items and about 11 lb of clothing, which fits a 40 liter bag with room for a toiletry kit.

What gets cut first, in order:

• Duplicate shoes. Wear the bulkiest pair on the plane and pack one pair of flats or sandals. Two pairs is the limit, and the third pair is always the one you never wear.
• Tops you packed for a mood. Five tops for seven days works if two of them are quick dry and you rinse them at day three. Nobody on the trip will remember what you wore twice.
• Bottoms beyond three. One pair of jeans or trousers, one pair of shorts, one pair that works for dinner. Three covers a week with a wash.
• The just in case layer. One mid layer plus the jacket you wear onto the plane covers 50 to 75 F. A second sweater is 1.2 lb of insurance you will not use.

The trim comes with a trade: you have to do one sink wash every 3 days. That is 10 minutes with a travel soap bar and a towel roll, and it is the price of skipping the baggage carousel. If you would rather not, check the bag and keep the 31 item list.

Wear the heaviest items on travel day. Boots, jeans, and the jacket take 3 to 4 lb out of the bag, and nobody weighs what you are wearing. That single trick is often the difference between a full carry-on and an overweight one.

Weather sets the layers

Weather sets the layer count, and the layer count sets the weight. Mild weather means one layer: a light jacket or a hoodie that handles a cool morning. Cold weather means two, plus gloves, a beanie, a scarf and a thermal base layer, which is 4 extra items that do not fit in a 40 liter bag alongside a 7 day list.

Hot weather cuts the layers to zero and adds swimwear if there is a pool or a beach. It also adds a practical problem: you sweat through a top in a day, so a hot trip wants two extra tops even though the formula does not count them. Treat 80 F and up as a 9 top trip, not a 7 top trip.

The spread from lightest to heaviest is 6 items and 5 lb, which is smaller than most people expect. Weather matters less to the count than laundry does, but it matters more to whether you enjoy the trip. A 45 F morning in a city with one thin layer is a bad morning, and the extra 1.2 lb is worth it.

Check the forecast for the destination, not for home, and check it three days out. The National Weather Service publishes a seven day forecast for every US zip code, which is enough lead time to swap a layer without repacking from scratch.

Activity sets the shoes and the gear

Activity decides the shoes, and shoes are the heaviest thing in the bag. City walking wants one broken-in pair of sneakers and one pair that looks better with dinner. Hiking wants boots plus a second pair for the evening, and a rain shell that packs into its own pocket. A beach trip wants sandals and a dry bag, and the sneakers can stay home.

Business travel is the exception to the half rule on bottoms. Two extra shirts and one extra pair of trousers come out to 34 items and 15 lb for a week, because a conference does not forgive a wrinkled shirt and there is no laundry in the plan. Pack a jacket that works with every outfit and one belt, and keep the shoes to two pairs that match everything.

Outdoor trips carry gear that is not clothing: a headlamp, a first aid kit, blister plasters, a water filter, and a warm mid layer. That gear takes volume, not weight, so the bag recommendation moves up a size even when the item count is similar. A 7 day hiking trip at 33 items is a checked bag, while a 7 day city trip at 31 items can squeeze into a carry-on with cubes.

One rule that saves a trip: break in the shoes before you go. Blister plasters are in the outdoor list because new boots on a 6 mile day are the most common way a hiking trip goes wrong. Wear the boots on two long walks at home first, and pack the plasters anyway.

Weight, bag size and the airline rules

Bag size follows the item count, and the airlines care about dimensions and weight more than they care about liters. A carry-on has to fit the sizer, which is 22 by 14 by 9 inches on most US carriers, and a checked bag has to stay under 50 lb before the overweight fee kicks in at $100 or more.

The 50 lb limit is the number that catches people, because a large bag packed full of clothes weighs 60 lb before you add shoes. Weigh the bag at home on a bathroom scale, holding it while you stand on the scale and subtracting your own weight. That is accurate to about a pound, which is enough.

Liquids are the other airline rule that changes the list. The TSA 3-1-1 rule limits carry-on liquids to 3.4 oz containers in one quart bag, so a full size shampoo has to be checked or decanted. The FAA passenger guidance covers what is allowed in carry-on and checked bags, and the CDC pack smart guide covers the health items worth adding, including prescriptions in their original bottles and a copy of the prescription.

Pack the bag, then take out one item. That is the oldest packing rule there is, and the calculator makes it concrete: the item you take out is usually the fourth bottom or the third pair of shoes, and you will not miss either.