Question: what happens when you don't pay your taxes on time?
Answer: If you file your taxes but don't pay them, the IRS can charge you a failure-to-pay penalty. The penalty is far less: Generally, the IRS will charge you 0.5% of your unpaid taxes for each month you don't pay, up to 25%. ... Just make sure you file within three years or the IRS is no longer required to pay you your refund."