$100 bills are the most common bill in circulation, even ahead of $1 bills.

One reason for this is $100 bills have a longer lifespan than smaller denominations, due to people using $100 bills less often for transactions. Some businesses may also decline $100 bills as payment.

Based on 2018 estimates from the Federal Reserve, a $100 bill has a lifespan of over 20 years, which is significantly higher than $1 bills (7 years) and $5 bills (5 years).