Motorists can pay in advance, either online, over the telephone, or by post.
On the day of travel, there are a variety of ways to pay:
Payment by text message requires registration with Transport for London in advance. Registration can also speed up payment by other methods.
To register, call 0845 900 1234 or visit Transport for London's congestion charge website.
Places where payments can be made in person display a congestion charging sign or PayPoint logo.
Motorists who have not paid by 10pm on the day of travel have to pay a £5 surcharge, bringing the total to £10.
Those who have not paid by midnight receive a penalty notice for an £80 fine, which is reduced to £40 if paid within 14 days.
Those who fail to pay the penalty charge within 28 days will be fined £120. Persistent non-payers may have their vehicles clamped and removed.