How much exchange rates really move in a day and a week

Article updated: 2026-10-17

Best rate USD · Bangkok: 33.65 — Superrich Thailand — Headquarter Rajdamri 1 · Oct 24, 19:45 → Details

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A lot of travellers arrive with a plan to “wait for a better rate”. They check the board on Monday, decide it looks low, and change on Thursday instead. Whether that ever works depends on a number most people have never looked up: how much the rate actually moves from one day to the next, compared with how much the choice of shop moves it.

The site keeps a daily record of the best buying rate in the country for each currency. This page uses the 30 days to 17 October 2026, which contain 26 recorded days, and sets the result against a different number: how far apart the shops were on a single day. Live boards refresh every few minutes on the Bangkok page; the history is on each currency’s rate page, for example the US dollar.

Thirty days of the best rate

For each currency, the lowest and highest daily best buying rate between 15 September and 17 October, the day each fell on, and where the series started and finished. “Range” is the gap from low to high as a share of the low.

For the major currencies the whole month’s swing, top to bottom, was between 1.0% and 2.3%: 43 satang on a dollar, 85 on a euro, 60 on a pound, 40 on a franc. On US$1,000, someone who sold on the best day of the month rather than the worst gained 430 baht; on €1,000, 850 baht; on £1,000, 600 baht. Those are the outer limits of what timing could have done with hindsight, and nobody has that. A single day or week sits inside that range, so no daily move in the period could have been worth more than the month’s 1.3% for dollars, and nearly all were worth far less.

Two currencies moved more. The won’s best rate ranged 4.55%, from 0.0242 to 0.0253, which on ₩1,000,000 is 1,100 baht. The rouble ranged 5.71%, between 0.35 and 0.37, and its best buying rate sits about 12% under its mid-market reference of 0.40; the rouble is thinly traded in Thailand and priced accordingly, so it is a special case rather than an argument for waiting.

What the start and end points hide

Low and high tell you the size of the swing. The start and end points tell you what waiting would actually have done, and in this month it cut both ways. The dollar finished 0.14 higher than it started, a gain of 0.4%, but it got there by way of a high of 33.61 on 5 October and then gave back 0.26 of it. The euro fell steadily and ended at its low, 37.40, so anyone who arrived with euros on 15 September and waited for a better rate waited into the worst day of the month. The yuan did the opposite and ended at its high, 5.03. The pound started at its high and never recovered it. The rouble ended exactly where it began.

Nothing on the board on 15 September said which of those would happen. The direction was not knowable, and the size, even over a month, was small.

The number to compare it with: the shop gap

On 16 October the gap between the best and the worst US dollar buying rate among Bangkok’s shops was 0.30 baht. With the best in the country at 33.35, the worst sat around 33.05, about 0.9% lower. On US$1,000 that is 300 baht for walking to a different counter the same afternoon.

The dollar’s entire best-day-to-worst-day range over the month was 0.43 baht. Choosing the shop on one day was therefore worth about 70% of what perfect timing over a whole month could have been worth, and the shop choice is certain while the timing is a guess. For reference, the best buying rate on 17 October, 33.35, sat 0.53% under the mid-market rate of 33.53, and the gap between the best buying rate and the cheapest selling rate for dollars on 16 October was only 0.05 baht: the top of the market is tight, the losses are at the bottom.

• Best Bangkok shop versus the worst: 0.9% on dollars, in one afternoon.
• The whole month’s range for the best rate: 1.3% on dollars, 2.3% on euros, 1.4% on pounds, with hindsight.
• One day inside that month: a fraction of either.

The conclusion is the opposite of market timing. You cannot predict tomorrow’s move, but you can choose the shop, the note size and the day of the week with certainty, and each is worth more than the move.

When waiting a day makes sense

• The counter in front of you is near the bottom of the range. If the board is 0.30 under the best in town, tomorrow’s shop choice is worth more than the month’s typical move. Change the minimum and go to a better counter in the morning. The airport comparison is the usual case.
• The good shops are closed. If the alternative tonight is a hotel desk or a 220-baht ATM fee for a small sum, sleeping on it costs nothing and the overnight move is noise.
• You have small notes and can get large ones. Not a timing decision, but a reason to pause: most boards pay a lower tier for small denominations, and swapping before you change is worth more than any day’s move.

When waiting costs more than it saves

• You are choosing between two good shops today. On 16 October the Bangkok mall counters paid between 33.17 and 33.33 for dollars, a few satang apart. Change now.
• You are paying to wait. Every day without baht that you cover with an ATM withdrawal costs a flat 220 baht plus your bank’s fee; see Thai ATM fees. On 10,000 baht that is 2.2%, more than the whole month’s range for the dollar.
• You are trying to catch a trend. The euro fell 2.2% over the month and the yuan rose 1.6%. Nothing on the board on the 15th told you which.
• The amount is small. On 5,000 baht of exchange, the whole month’s dollar range was worth 65 baht, and a single day’s move a small fraction of that.

Who does not need to think about this at all

Anyone changing a normal holiday amount. On US$1,000, perfect timing over the month was worth 430 baht with hindsight, a day’s wait a small fraction of that, and the choice of shop 300 baht with certainty. Pick a good counter in business hours, bring large notes, and stop watching the chart. The US dollar rate page is there if you enjoy it, not because you need it.

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