What the calculator applies
- Schedule. Form 945 uses the Form 941 deposit rules with an annual lookback: the tax on the Form 945 filed for "the second calendar year preceding the current calendar year." $50,000 or less makes you a monthly depositor, due the 15th of the following month; more makes you semiweekly, due the following Wednesday for Wednesday-to-Friday liabilities and the following Friday for Saturday-to-Tuesday, always with at least three business days after the period (IRM 20.1.4.8.2 to 8.5). A new payer with no lookback is monthly.
- The $100,000 rule. Accumulating $100,000 in a deposit period makes that amount due the next business day, and a monthly depositor "immediately becomes a semi-weekly depositor for the remainder of the current calendar year and the following calendar year" (IRM 20.1.4.8.6).
- Business days. Only Washington, D.C. legal holidays move a due date; state holidays do not, "as [deposits] are made by EFTPS" (IRM 20.1.4.7.3).
- The tiers. 2% one to five days late, 5% six to fifteen, 10% more than fifteen, and 10% for "required deposits not paid by EFT"; a further 5% attaches to tax still unpaid more than ten days after the first notice, which this tool flags but does not add (IRM 20.1.4.7.1).
- Application. By default "deposits are applied to the most recently ended deposit period or periods" (Rev. Proc. 2001-58; IRM 20.1.4.7.4(11)). Within 90 days of a penalty notice you may designate the order instead, including oldest-first, and "Do not assess the additional penalty unless the taxpayer agrees" if the designation raises it (IRM 20.1.4.26.3). Toggle the setting to compare.
- Safe harbor. No penalty on a shortfall of no more than the greater of $100 or 2% of the amount due, if it is made up by the return due date (monthly) or by the earlier of the first Wednesday or Friday on or after the 15th of the following month and the return due date (semiweekly) (IRM 20.1.4.8.7).
- Under $2,500. If total tax for the year is under $2,500 no deposits are required and the tax may be paid with the return. At $2,500 or more, "any amount paid with the return is subject to the 10 percent avoidance penalty" (IRM 20.1.4.6(6)); the test is annual, with no prior-year lookback as on Form 941.
What it does not do
It does not compute failure-to-file or failure-to-pay penalties on the return itself (see the Form 945 page: no FTF if deposits covered 100% by January 31, no 60-day minimum), interest, or the averaged penalty the IRS assesses when the Form 945-A is missing or does not add to line 3 (IRM 20.1.4.18). It assumes each deposit was made through EFTPS unless marked otherwise, and that no CP 161 has issued. Figures are estimates; the FTDPN computation on a CP 210 or CP 568 controls.