I know I paid at least one of my quarterly estimated tax payments in 2016 but I don't know the amount I paid. Is there a way to find that?

[ThomasM · Accepted solution]

The simplest way would be to get a Tax Account Transcript from the IRS, which will show any payments you've made (among other things).  You can do this online.  Here's the link: https://www.irs.gov/individuals/get-transcript.