Form 945 Explained: How Small Businesses Report Backup Withholding and Nonpayroll Withholding Once a Year

You paid a contractor $5,000 but sent only $3,800, because no signed W-9 ever came back and the rules say you must hold back 24 percent. That missing $1,200 is not your money to keep, spend, or forget about — it is federal income tax you now owe the IRS on someone else's behalf. Form 945, the Annual Return of Withheld Federal Income Tax, is the once-a-year form that reports it and settles the account.

Most small businesses meet Form 945 through backup withholding: a missing or incorrect taxpayer identification number forces you to withhold from a 1099 payment, and that withholding has to be deposited and reported somewhere. That somewhere is Form 945 — not your payroll return, not your income tax return, and not a form you can skip because you have no employees. This guide explains what the form covers, when deposits are due, how the filing deadline works, and the simple workflow that keeps you out of penalty territory.

What Form 945 Is (and Is Not)​

Form 945 is the IRS annual return for federal income tax withheld from nonpayroll payments. You file exactly one per calendar year if you withheld — or were required to withhold — during that year. If you had no nonpayroll tax liability in a given year, you simply do not file; there is no zero return to submit.

Three boundaries matter more than anything else on this form:

• It is not a payroll return. Wages, salaries, and the withholding on them belong on Form 941 (quarterly), Form 944, Form 943, or Schedule H — never on Form 945. The IRS instructions state this separation explicitly, and mixing the two is one of the most common errors small filers make.
• It is not an information return. Forms 1099-NEC, 1099-MISC, 1099-R, and W-2G tell each payee (and the IRS) what was paid and what was withheld. Form 945 is the summary return that totals all of that withholding across every payee and reconciles it against what you deposited.
• It covers only nonpayroll withholding. Pensions, annuities, IRA distributions, military retirement pay, gambling winnings, certain government payments, and backup withholding on reportable payments all land here. Foreign-person withholding reportable on Form 1042 stays off this form.

Think of it this way: your 1099s are the itemized receipts, and Form 945 is the annual statement total. The IRS computers compare the two, so they must agree.

The Two Kinds of Withholding on the Form​

Form 945 has two income lines, and knowing which line your withholding belongs on prevents the most basic filing mistake.

Line 1: withholding from pensions, annuities, and similar payments. This covers federal income tax withheld from pension distributions (including 401(k), 403(b), and governmental 457(b) plan distributions), annuities, IRA distributions, military retirement, Indian gaming profits, and gambling winnings under the regular gambling withholding rules. It also includes voluntary withholding amounts on certain government payments. Most small businesses with no retirement-plan distributions and no gambling operations leave this line at zero — and that is perfectly normal.

Line 2: backup withholding. This is the line small businesses actually use. Enter all backup withholding you withheld or were required to withhold during the year, including backup withholding on gambling winnings. The flat rate is 24 percent of the reportable payment.

Line 3 adds the two lines together. That total drives nearly every rule that follows: whether you must make deposits during the year, whether you complete the monthly liability summary, and which deposit schedule applies to you next year.

When Backup Withholding Hits a Small Business​

Backup withholding is the mechanism that protects the Treasury when a payee's tax identity is unreliable. As the payer, you become the collection agent. It applies at 24 percent when any of these conditions is met:

• No TIN on file. The contractor, freelancer, or vendor never gave you a completed Form W-9 with a valid taxpayer identification number before you paid them.
• An incorrect TIN. The name and number combination does not match IRS records — the classic trigger is a CP2100 or CP2100A notice listing your incorrect filings, where small payers with fewer than 50 problem returns receive the CP2100A version.
• IRS notification. The IRS has specifically instructed you to impose backup withholding on a payee, for example after the payee underreported interest or dividends.

The CP2100 notice starts a compliance clock you should take seriously. Generally, you must send the payee a first B-notice with a blank W-9 within 15 business days of receiving the notice, and begin backup withholding on future payments if the payee does not respond with a certified TIN within 30 business days. A payee who triggers a second notice within three years faces stricter treatment, including withholding that starts immediately. The practical lesson: a CP2100 is not junk mail. Calendar it the day it arrives.

Also note the reporting threshold landscape is shifting. For payments made starting January 1, 2026, the One Big Beautiful Bill Act raises the 1099-NEC and 1099-MISC reporting threshold from $600 to $2,000, with a matching change to the backup withholding threshold. Confirm the current-year threshold before each filing season rather than relying on the $600 figure from memory.

Deposits: The $2,500 Rule and Your Schedule​

Withholding you hold is trust-fund money — it belongs to the Treasury from the moment you withhold it — so the deposit rules are strict.

Under $2,500 for the year: pay with the return. If your total Form 945 tax for the year (line 3) is less than $2,500, you are not required to make deposits during the year. You may simply pay the balance when you file. This covers the great majority of small businesses that withhold only occasionally.

$2,500 or more: deposit on schedule. Larger liabilities must be deposited during the year by electronic funds transfer — through EFTPS, IRS Direct Pay, or your IRS business tax account. Two details trip people up:

• Never combine Form 945 deposits with payroll deposits. Deposits for Forms 941, 943, 944, or CT-1 are a separate stream with separate liability accounting. Do not net them, do not swap them, and do not use one return's schedule to time the other's deposits.
• Your schedule comes from a lookback. Before each calendar year, determine whether you are a monthly or semiweekly schedule depositor based on the total tax reported on your Form 945 from two years earlier: $50,000 or less on that line 3 means monthly; more than $50,000 means semiweekly. And if you are a monthly depositor who accumulates $100,000 or more of liability on any single day, you convert to semiweekly starting the next day — for the rest of that year and all of the next one.

Filing: Deadline, Liability Summary, and Reconciliation​

The deadline is January 31 of the year after the withholding occurred — the same day 1099s go to recipients. If that date falls on a weekend or legal holiday, it moves to the next business day (for the 2025 tax year, that means February 2, 2026). Only one narrow extension exists: if you made all required deposits on time and in full, you may file by February 10 instead. There is no general extension for Form 945, so plan the January workload accordingly.

The liability summary depends on your size and schedule. This section reports when the liability arose during the year — it is a summary of monthly liabilities, not of deposits made:

• If line 3 is less than $2,500, skip the summary entirely.
• If you were a monthly schedule depositor for the whole year and line 3 is $2,500 or more, complete the line 7 monthly summary on the form itself.
• If you were a semiweekly depositor at any point — including a midyear conversion triggered by the $100,000 next-day rule — report the full year's liabilities on Form 945-A instead and attach it.

Two consistency checks close the loop. First, the name and EIN on Form 945 must exactly match the name and EIN on the information returns reporting the withholding; a mismatch causes processing delays and can generate penalties. Never use a Social Security number where an EIN is requested. Second, reconcile before you file: the federal income tax withheld shown across your Forms 1099 (Box 4 on the NEC and MISC, for example) should tie to the Form 945 total, allowing for the non-1099 withholding types the form also carries. Discovering a gap in January is a fix; discovering it in an IRS notice is a penalty.

If you find an error after filing, correct it with Form 945-X rather than filing a second Form 945 — only one Form 945 per year is ever allowed.

Penalties for Getting It Wrong​

The penalty stack on Form 945 is the standard employment-tax stack, and it compounds:

• Late filing generally runs 5 percent of the unpaid tax per month or part of a month, up to 25 percent, unless the delay was due to reasonable cause rather than willful neglect.
• Late deposits and late payments draw their own failure-to-deposit and failure-to-pay penalties plus interest, which accrues from the due date until the balance is paid.
• Information-return failures — missing or incorrect 1099s, or missing payee statements — carry separate per-return penalties that scale with how late the correction comes.
• Trust fund recovery is the severe backstop: responsible persons can be held personally liable for 100 percent of withheld tax that was never turned over.

None of these require intent to evade. Ordinary neglect — forgetting the January 31 deadline, netting 945 deposits into payroll deposits, ignoring a CP2100 — is enough. The defense the statute recognizes is reasonable cause, and the way you build it is a documented routine.

A Simple Compliance Workflow for Small Payers​

You do not need a tax department to handle Form 945 correctly. You need a short routine, run the same way every time:

1. Collect a W-9 before the first payment. Make a signed W-9 a condition of vendor onboarding, not a January scramble. No W-9 means backup withholding starts with the first check — and contractors return the form remarkably fast once 24 percent of each payment stops arriving.
2. Validate TINs early. The IRS TIN Matching service lets you verify name-and-number combinations before you file information returns, which prevents most CP2100 notices from ever happening.
3. Respond to every CP2100 within days. Log the notice date, send the B-notice inside the 15-business-day window, and calendar the 30-business-day withholding start date. File copies of everything you send.
4. Track withheld amounts in their own liability account. Every time you withhold, credit a dedicated backup-withholding-payable account rather than letting the cash sit invisibly in operating funds. At year-end, that account balance is your Form 945 line 2 before reconciliation — one number to check instead of a year's worth of payment records to re-add. The bookkeeping documentation covers how a dedicated liability account keeps trust-fund money visible until it is deposited.
5. Deposit on schedule and separately. If you cross the $2,500 line, deposit by EFT on your assigned schedule, and keep the 945 deposit stream physically separate from payroll deposits.
6. Reconcile 1099s to the return in January. Tie every Box 4 withholding figure to the Form 945 total, confirm the EIN matches everywhere, then file by January 31.

Keep Your Withholding Records Audit-Ready​

Backup withholding usually starts as a paperwork gap — a missing W-9, an unanswered notice — and turns into a penalty only when the tracking is sloppy. Keeping withheld amounts in a dedicated liability account, with every deposit traceable to the payment it came from, is what makes January reconciliation a review instead of a reconstruction. Beancount.io provides plain-text accounting that gives you complete transparency and control over your financial data — no black boxes, no vendor lock-in. Get started for free and see why developers and finance professionals are switching to plain-text accounting.