The mid-market rate, and why no shop will ever give it to you
Article updated: 2026-09-17
Best rate USD · Bangkok: 33.24 — Superrich Thailand — Headquarter Rajdamri 1 · Sep 20, 08:58 → Details
Search for an exchange rate and you get a single confident number. That number is the mid-market rate, and it is the most useful figure in this whole subject as long as you understand one thing about it: it is not a price. Nobody will sell you currency at it, and nobody will buy currency from you at it. It is the midpoint between two prices that do exist.
Understanding that turns it from a source of grievance into a measuring stick, which is what it is good for.
Where the number comes from
Banks trade currency with each other continuously. At any moment there is a price at which the market will buy dollars for baht, and a slightly higher price at which it will sell them. The midpoint between those two is the mid-market rate. It is also called the interbank rate, the spot rate, or on this site the reference rate.
Google, Reuters, XE and your banking app all show a version of it. They differ slightly because they sample different feeds at slightly different moments, and because currency has no single exchange the way a listed share does.
What matters is that it is a wholesale midpoint between institutions trading millions at a time, electronically, with no cash involved at all.
Why a shop cannot match it
A money changer is not doing what a bank’s trading desk does. It is running a shop with physical banknotes in it, and every one of those differences costs something.
It holds inventory it cannot use. A counter has to have dollars, euros, yen and baht sitting in a drawer in case someone walks in. That money earns nothing while it waits, and the rate can move against the shop while it sits there.
It takes the currency risk. Between buying your dollars at 10:00 and selling them on, the market moves. The shop is carrying that risk, not you.
It physically moves cash. Notes get counted, checked, bundled, insured and driven to a bank. Small denominations cost more to handle per unit of value, which is exactly why the board has separate lines for them.
It has costs a trading desk does not. A lease on a shopfront in a tourist district, staff, a licence from the Bank of Thailand, security, a safe, cameras.
It sometimes eats a loss. A note that turns out to be counterfeit, or that the bank downgrades for condition, is the shop’s problem.
The buying and selling columns on the board are where the shop covers all of that. The gap between them is its margin, not a fee it is hiding from you.
What a fair gap looks like in Thailand
This is the part worth memorising, because Thailand is genuinely good on this measure.
- A competitive Bangkok cash counter on a major currency sits within roughly 1% of the mid-market rate on the buying side. On US dollars at the tightest shops it can be a fraction of that.
- A typical Thai cash counter in a tourist area is somewhere in the 1–3% band.
- An airport arrival-hall counter is several per cent behind the city, which is the whole subject of airport versus city rates.
- A bank branch is usually worse than a dedicated money changer, which surprises people.
- A hotel front desk is the worst rate you will be offered anywhere in the country.
For comparison, the equivalent in most of Europe, North America and Australia is considerably wider. This is why experienced travellers bring cash to Thailand rather than relying on cards. The cash market here is unusually competitive.
How to use it as a measuring stick
The mid-market rate answers one question well: is this counter treating me normally?
Take the mid-market rate for your currency. Compare it to the buying rate on the board. Work out the percentage gap. Then:
- Under about 1% — you are at a genuinely competitive counter. Change your money and stop optimising.
- 1–3% — normal for a tourist district or a smaller town. Fine for a modest amount; worth a short walk if you are changing a lot.
- Over 3% — you are paying for location. That is a rational choice in an airport at midnight and a poor one on a Tuesday afternoon in Bangkok.
The arithmetic is easier in absolute terms. On the equivalent of US$1,000, one per cent is about 350 baht. That is a decent dinner, and also roughly what a taxi across Bangkok costs — which is why walking twenty minutes to save half a per cent on a small amount is not worth anyone’s afternoon.
What the mid-market rate is genuinely good for
Judging a card. WiseAd and Revolut advertise conversion “at the mid-market rate” plus a stated fee. That claim is checkable in a way a shop’s is not, and it is the basis of the comparison in Wise, Revolut or a plain debit card.
Spotting dynamic currency conversion. When a terminal offers to charge you in your home currency, compare its rate to the mid-market one. The gap is typically 3–8%, and that is the whole point of refusing DCC.
Budgeting before the trip. For working out roughly what a week costs, the mid-market rate is close enough. Nobody needs three decimal places to plan a holiday.
Watching a trend. If the mid-market rate has moved several per cent in your favour over a month, that is a real change. Day-to-day wiggles are noise.
What it is not good for
It is not a rate to demand. Walking into a counter with a phone screen showing Google’s number and asking why the board is different is a conversation that goes nowhere, because the board is a retail price and the screen is a wholesale midpoint. The staff member cannot change it and did not set it.
It is also not a promise. Rates move during the day and boards are updated several times. The rate that binds is the one on the board when you hand over your money, which is the point made in how to read a rate board.
Who does not need this
- Anyone changing under the equivalent of a couple of hundred dollars. The difference between the best counter in Bangkok and a merely decent one, on that amount, is small change. Use a reputable shop near you and get on with your day.
- Anyone paying by card for everything. Your exchange rate is set by Visa or Mastercard, published daily, and already close to mid-market. Your real costs are your issuer’s foreign transaction fee, the 220-baht ATM fee if you withdraw, and DCC if you accept it.
- Anyone at the airport at 01:00 with no baht. You already know the rate is poor. Change the minimum, go, and do the real exchange tomorrow. Optimising at that moment is not available to you.
- Anyone who finds this stressful. Thailand’s cash market is competitive enough that an ordinary tourist-district counter is not a trap. The mid-market rate is a tool for people who want to check. It is not a test you can fail.
This site publishes the reference rate next to every shop’s published board and reads those boards directly from the shops’ own sites, so you can see the gap rather than guess at it. Start on the Bangkok page or the shop directory.