How it works
The IRS accepts card payments through approved third-party processors. Each charges a percentage fee for credit cards.
The fee is charged by the processor, not by your issuer, and it is a purchase on your card.
State and local taxes often use other processors with different fees.
The arithmetic
A 2% card paying a fee just under 2% earns almost nothing.
A 1.5% card loses money.
A large sign-up bonus can make the fee worth paying, if taxes are the only way to reach the spend.
Before you pay
Make sure you can pay the card in full. Card interest costs far more than any reward.
A large tax payment can raise your utilization temporarily.
Check that the processor's transaction is coded as a purchase by your issuer. It normally is.
