The Vietnamese currency is the đồng, and it is represented by the symbol ₫.
A rough guide: US$1 = VND20,000. Yes, that’s 20 thousands Dong. Well technically it is about US$1 = VND22,000 but rounding off makes it easier to remember and calculate.
A common myth: You can use US dollars freely and they are legally accepted.
Can I Use US Dollars in Vietnam?
Legally, all transaction must be done in the dong. But almost everyone will accept the greenback. However, using the dollar does not necessarily mean that you are getting an upper hand.
If you use US dollars to pay a street vendor, he will give you a crappy exchange rate and you cannot even bargain, or you will not even get any change back! And even if the rate is poor your mind will be racing like mad trying to figure out how much will that be in your local currency.
If you go to a restaurant and request to pay in US$, you will get one of the worst exchange rate in this world. The only time you will get a better exchange rate is when you change your money with a black market money exchanger.
So just use DONG. I only use US dollars when I want to buy something expensive and carrying the equivalent of DONG will mean carrying two kilos of money in my backpack, and waiting 20 minutes for the staff to count the notes.
As the Vietnam Dong is not an international traded currency, whatever rate you get back home cannot match those money changer in Vietnam. You may want to change US$50 at home so you can use it for taxi, purchase a drink, etc.
The largest Dong denomination is VND500,000. Haha, yes half a million dong. That is about US$25. So imagine buying a air conditioning units that cost US$2,000. Always ask for smaller denomination if possible. Taking a short taxi trip will only cost VND30,000 and if you give the driver a VND500,000 note he will just shrug and tell you he has no change for that, or worse short change you, or worst will not give you any change back.
For tipping, it is fine if you tip in your own nation’s currency or US dollars.