The uncapped sale is designed to raise as much capital as possible. This is done by fixing the time of the sale and, typically, the number of tokens available. As people buy in, they receive a share of tokens equal to their share of the total capital invested. The number of tokens each person receives is often not known until the end of the ICO. For instance, if, on day 1 an investor puts in $10,000 and no one else bids, they would own all of the available tokens. However, the next day, another investor puts in $10,000 as well. If this were the end of the sale, the two investors would each own half the available tokens.

Such as the capped sale, there are many variations. The EOS token sale is probably the best-known version of the uncapped sale. The EOS token was sold over 341 days, with a few more tokens being made available for purchase each day.