I have filed my 2018 tax return and now want to contribute to my 2018 HSA as i didn't exceed the contribution limit and my HSA is allowing me to do it. What i wanted to know is am i able to claim that 2018 contribution i make as a deductible in my 2019 tax returns next year? or i have to file some kind of amended tax return before April 15th this year? and if the second would that be more complicated than it's worth? i will be contributing around $3000.
