London and all of the U.K. is clinging on to its monetary system, despite being a member of the Euro-using European Union. British Pounds Sterling are used in the following denominations: £50, £20, £10 and £5 notes and £2, £1, 50p, 20p, 10p, 5p, 2p, and 1p coins. (You’re going to end up with a lot of those coins, so bring an extra large change purse!)

The conversion rate is currently £1 = $1.86 US. There are plenty of available currency calculators, as well as free software for your handheld devices, that you can find online. Mentally calculating 2-for-1 seems to work fine as an alternative.

While you will find yourself using credit cards for most of your purchases (Visa, MasterCard and American Express are readily accepted virtually everywhere), keep in mind that many retailers are now able to charge more for goods and services if you pay this way. Keep an eye out for signage about this pricing differential. They’re obligated to post this when it occurs.

You’ll need cash for taxis, as well as small purchases and meals. There’s no limit on the amount of US dollars you can bring into the country, but you’ll have to exchange it into pounds for use within London and environs. There are plenty of places to exchange money, but be cautious and read the posted exchange rates and ask about fees. Airports, railroad stations and the Bureaux de Change in the high streets can cost you money – you may want to visit a bank or use an ATM. If you have a Visa debit card, you can use Plus System ATMs. For MasterCard debit cards, use any Cirrus machines. While I’ve never heard of anyone’s debit card having difficulties in the U.K. (i.e. being “eaten” by the machine), it’s always a good idea to have some sort of backup system or reserve, such as travelers’ checks, for emergencies. Also, make sure you jot down a phone number for your bank back home in case you run into difficulties – and be sure to inform them that you’ll be using your debit card overseas. They’ll log the dates in their system.

You’ll also want cash for gratuities. While you’re welcome to tip whatever you think is appropriate, it’s customary to offer 10-15% of the hotel and restaurant bills to the staff and waitpersons who have served you. (Some restaurants add service fees to the bill – always remember to check before “double tipping.”) If someone shows you to your hotel room and takes your bags up, offer at least 75p-£1 per suitcase. Taxi drivers should get 10-15% of the journey’s cost.