How long does it take the IRS to post my payment?
Successfully completed payments are sent to the IRS on the next business day. It usually takes the IRS 5 to 7 days to post the payment. However, when they post this payment it will be posted with an effective date of the successfully completed payment.
If the due date for an estimated tax payment falls on a Saturday, Sunday, or legal holiday, the payment will be on time if you make it on the next day that isn’t a Saturday, Sunday, or a holiday. See Pub. 509 for a list of all legal holidays.
January payment.
If you file your 2024 Form 1040 or 1040-SR by January 31, 2025, and pay the rest of the tax you owe, you don’t need to make the payment due on January 15, 2025.