Short answer
For 3 days, protect the core temple-river, modern shopping and Chinatown/market layers. At 4–5 days, separate the zones and add one optional outing. At 6–7 days, slow the pace further with family/rest time or one larger extension. Heat and traffic are part of the route decision.
In this guide
Use the duration to control how many zones you take on
3 days: core Bangkok
A compact three-day shape is:
- temple + river day
- Siam / Sukhumvit day
- Chinatown / market / slower day
That is enough structure for a first trip without turning each day into a city-wide zigzag.
4–5 days: separate the zones
With more time, give major areas their own space and consider Ari/Thonglor or one optional day trip.
6–7 days: add slower or family pacing
A longer trip can support more rest, pool time, a larger excursion such as Ayutthaya, or market-focused days.
Build the day around heat
A practical rhythm is one main sight + one indoor break + one flexible evening.
Temples fit better earlier. Midday is the natural indoor/rest block. Markets and river areas can shift later.
Respect date-dependent markets and excursions
Chatuchak depends on the day of week. Floating/railway-market outings and Ayutthaya are larger commitments than a neighbourhood stop.
Keep them optional rather than forcing them into every first visit.
Final decision
Three days for the core, 4–5 for better zone separation, 6–7 for a slower or excursion-rich trip. The main rule is to reduce unnecessary cross-city movement and use heat/traffic tolerance as a real constraint.