Underpayment of tax penalty

I will be paying a lot on federal and state returns due to interest income from high yield savings and cds. Do I just have to pay these and everything will be good? What is this underpayment of tax penalty? When I filled out my tax in Turbotax, it states that I need to calculate this or have IRS calculate it for me. This has not happened to me before as in the prior years, I had little interest income from savings due to interest rates being so low.