How many people are going?The budget below updates to match.
Budget
The big shared purchases for the whole group. Food, transit and attraction tickets are left out. €1 = $.
Total, for 3 travelers
flights, lodging, Eurostar and extras
Per person
if everything is split evenly
Item
Group
Each
Day by day
Sunset is around 4:30pm, so outdoor things go mid-day and museums and lights go later.
Book these now
The trip is four weeks out. Cheap Eurostar fares and popular timeslots go first. Book everyone in one order so you get seats and slots together. Ticks are saved in your own browser only, so they won't show up for anyone else.
Good to know
ETIAS isn't required for this trip. It has no launch date yet, and there's a transition period once it starts.
Amsterdam: each person taps their own Visa or Mastercard (not Amex) in and out on trams and trains. One card can't pay for the group.
Paris: one Navigo Easy card each. The CDG airport ticket can't share a card with regular tickets, so buy it Monday morning.
Sunset is around 4:30pm. Do outdoor stuff mid-day, museums and lights later.
Lunch is easy to walk into, but book dinners on Fri and Sat, especially in Paris.
Splitting costs: one person books each group purchase and the others pay them back. A shared expense app (Splitwise or similar) keeps it simple.
Assumptions
The euro rate is €1 = $1.16.
Flights: the first two seats are ≈$810 each, backed out of the original two-person budget. Each seat booked now is estimated at ≈$1,000 until it's actually booked.
Amsterdam hotel: $583 for one room for 4 nights. Rooms are doubles, and an odd person out turns one double into a triple (+$200).
Paris Airbnb: $700 for two, plus ≈$120 for each extra guest (fee and city tax). This assumes the place sleeps everyone.
Eurostar is estimated at €80 each. Being four weeks out and booking seats together pushes the typical €55–99 fare up.
Trip-wide extras are ≈$172 per person (the original $343 for two).
Food, local transit, museum and attraction tickets aren't included in the budget.
Card foreign-transaction fees can add 1–3% unless you use a no-FX-fee card.