I mistakenly put the wrong amount for my first stimulus payment. Will I be penalized?

[JohnW152]

It's extremely unlikely that you’d be penalized.

If the IRS makes an error in your favor based on the information entered, you'll need to pay back the erroneous overpayment and perhaps interest, but there shouldn't be an actual penalty.

If you're saying that you input the wrong amount for the first stimulus you received in the TurboTax Online program, and you haven't submitted your return yet, simply type stimulus into the Search box and enter.  Then, if you'll click the link "Jump to stimulus," you'll be prompted to enter your amount(s) again.

The IRS requires you to report all relevant stimulus information when you’re filing your return.

[Opus 17]

What we think will happen is that the IRS will automatically adjust your tax return, under the usual rules they use to correct math mistakes.  However, this may kick your return out of the automated system and send it for human review, which will likely delay payment of the rest of your refund.

It is also possible they will pay the wrong amount and then bill you for it later (with interest), or they might reject your return when they open e-filing in February, in which case you can fix it before re-transmitting.  It's too early to know exactly what will happen since the IRS has not opened tax return processing yet. 

[luravevian]

I did not put down the full amount for the first stimulus payment. I have already efiled taxes but it has not been sent to the IRS can I correct it from it is sent?

[Opus 17]

It is not possible to recall your tax return from Turbotax.  You will have to wait and see what the IRS does.