Pack for a wash cycle, not for the whole trip
The usual way to pack is to count the nights and multiply. It is why a fortnight looks like a suitcase and why people come home with clothes they never opened.
The number that actually decides the size of the bag is not the length of the trip. It is whether you can wash anything while you are there.
The wash-cycle rule
With no laundry, you pack for the whole trip: the clothing count is the number of nights.
With laundry, you pack for one wash cycle plus a spare, and the trip length stops mattering past about four days. Take the number of nights, cap it at four, add one. That is your base.
Which produces the result that makes the rule obvious: a fortnight with a washing machine packs exactly the same as five days without one. Fourteen nights capped at four is four, plus one is five. Five nights with no laundry is five. Same bag, one is nearly three times as long.
Everything else follows from the base
Once you have a base number, the rest is division, and division is why you do not need one of everything per day:
- Tops: the base.
- Trousers or bottoms: the base divided by three, rounded up. Bottoms get worn more than once; this is where over-packing usually happens.
- Underwear and socks: the base plus one. The spare is deliberate — it is the cheapest, smallest, lightest insurance in the bag.
- Sleepwear: the base divided by five, rounded up.
Worked through on a base of five: five tops, two bottoms (five divided by three is 1.67, rounded up to 2), six underwear, six pairs of socks, one set of sleepwear. That is a carry-on.
Run it again for ten nights with no laundry, so the base is ten: ten tops, four bottoms (ten divided by three is 3.33, rounded up to 4), eleven underwear, eleven socks, two sets of sleepwear. Still not a wardrobe, and now it is a decision rather than a guess.
Climate changes the layers, not the counts
The clothing arithmetic does not change when it gets cold; the additions do. Cold means a warm coat, hat, gloves and scarf, base layers and waterproof boots — bulk, not quantity. Hot means a sun hat, sunglasses, one light long-sleeved layer for sun cover, and sandals plus one pair of closed shoes, because feet that have only sandals are feet that cannot walk far. Mild means a light jacket, a compact umbrella and shoes you can actually walk in.
The categories that stop things being forgotten
Clothing is the part people think about, which is why it is rarely the part that goes wrong. Group the rest so the gaps show:
- Toiletries — including any prescription medicines in their original boxes, and a small kit with plasters, painkillers and an antihistamine.
- Documents and money — passport or identity document, and check the expiry date now, not at the airport. Tickets, insurance details, cards, a little local cash, and copies of the key documents kept somewhere separate from the originals.
- Electronics — phone, charger, travel plug adapter, power bank, headphones.
- Trip extras — what a camping trip needs is not what a business trip needs, and neither is a beach trip.
Children get their own section, because the failure mode there is different: the missing item is rarely clothing.
The builder
The Packing List Builder asks the five questions that change the answer — nights, climate, trip type, laundry, children — and prints the list with the counts already worked out. It does not know your airline's baggage allowance or liquid limits, and it does not guess at them; those vary by carrier and destination, so check yours before you pack.
The counts are a starting point, not a prescription. Adjust for how you actually dress, and for anything you already know you will buy when you get there.