TurboTax rounds estimated tax payments; the IRS and CA FTB do not

[user68564]

2025 was the first time I made estimated tax payments. For reasons that don't matter, I ended up making some payments to the penny instead of round numbers. After I entered my estimated tax payments into TurboTax, it rounded the payment figures. After submitting my returns and getting my refunds, I see now that, unlike TurboTax, the IRS and the CA FTB use the exact payment figures to calculate my refund to the penny. Given that this is apparently normal, expected, and predictable behavior by tax authorities, it seems odd that TurboTax rounds the figures instead of using the exact amounts to calculate the refund. TurboTax should use the exact figures given that the tax authorities do so. 

Of course, now that I know this, going forward I will only make round payments, which will avoid this issue, but this is odd on the part of TurboTax. 

[Mike9241]

don't know about CA, but the IRS certainly does allow rounding. 49 cents or less, the lower whole number. 50 cents or more the higher whole number.  if you don't like TurboTax's rounding on estimates, nothing prevents you from crossing out the amount on the voucher and writing any number you want 

[user68564]

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@Mike9241 wrote:

don't know about CA, but the IRS certainly does allow rounding. 49 cents or less, the lower whole number. 50 cents or more the higher whole number.  if you don't like TurboTax's rounding on estimates, nothing prevents you from crossing out the amount on the voucher and writing any number you want 

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Voucher? I'm not talking about the vouchers. And you're talking about rounding other figures related to income. Yes, the IRS rounds those. I'm talking about the actual estimated tax payments made. The IRS does not allow for rounding those. It will use your actual unrounded payments when calculating your refund. I did "make any payment I want" as you suggest, and while TurboTax rounded it, the IRS did not. Are you sure you understood my post? Let me illustrate. 

Suppose you made the following estimated tax payments:

Q1 1,000.20

Q2 1,000.20

Q3 1,000.20

Q4 1,000.20

And let's say TurboTax calculates your total tax as $3500. It will indicate your refund is $4001-$3500, or $501. The IRS, however, will not refund $501 because you didn't pay $4001. You paid $4000.80. So your refund will be $500.80. So even though TurboTax rounded your payments, the IRS does not. 

And the point is not the 20 cents, in the example. The point is that TurboTax should get it right, since the IRS and CA FTB (at least) do NOT round the payments. 

Note: the figures used in the above example are for illustration purposes only.