I get a Federal refund of $348 and I owe Colorado $723. The 2018 Form 1040-ES Payment Voucher indicates I should send the IRS a check for $477. Please explain/advise. ?

[VolvoGirl · Accepted solution]

Those are not for your tax due.  Those are 1040ES quarterly estimated payments for NEXT YEAR.  They are pre-payments so you don't end up owing again next year.  They are optional to pay and don't get sent with your return. 

If you are getting a refund, They might have printed out if you got a big one time increase in income.   like if you took a IRA or 401K Withdrawal or had a big stock gain.  They are optional to pay.  They don't get sent in with your tax return so the IRS won't be expecting them.  You can ignore them.