Two full days is the minimum for Bangkok; three is better. Two covers the Grand Palace, Wat Pho, the river and one market. The third adds a day trip (Ayutthaya) or a slower neighbourhood day. Beyond three days you should leave the city.
The short version
- Two days: old city, river, one market. Enough for a stopover.
- Three days: add Ayutthaya or a canal morning. This is the sweet spot.
- Four days: only if you are using Bangkok as a base for day trips.
- Split days by geography — the traffic makes crossing the city expensive.
Two days: the essentials
Day one for the old city — Grand Palace, Wat Pho, Wat Arun — and day two for markets and the river. That is enough to understand the city without exhausting yourself.
Do not try to see everything on day one. The heat is the limiting factor, not the distance.
Three days: add one thing properly
A floating market, a cooking class, or a day at Ayutthaya. Each is a half or full day and each is better than squeezing in a fourth temple.
Three days also gives you an evening that is not scheduled, which is when Bangkok is at its best.
When to leave
If you have four days, spend two of them outside the city: Kanchanaburi or Ayutthaya. Bangkok's best quality is as a base, not a destination in itself.
What a fourth day actually adds
The fourth day in Bangkok is the day people either love the city or decide they have seen it. It is not another temple — it is a day trip. Ayutthaya (1.5 hours by train or road) is the obvious one, and it is genuinely worth a full day rather than an afternoon.
The alternatives are Kanchanaburi for the railway and the war museums, Khao Yai if you want jungle, or Maeklong and Amphawa for the railway market and the evening boats. All four are 1.5–2.5 hours from the city and all four are better than a fourth day of temples.
If you are not taking a day trip, the fourth day should be a district you have not seen: Bang Krachao by bicycle, Talat Noi behind Chinatown, or the river by public ferry with no destination. Bangkok rewards slow wandering more than it rewards lists, which is why the people who hate it are usually the ones who scheduled it.
