Freelance Year-End Tax Checklist: What to Do Before December 31

December 31 is a hard cutoff for most tax moves. The decisions you make — or skip — in the last six weeks of the year show up directly on what you owe in April. Here is what actually matters.

Pay your Q4 estimated taxes on time

The Q4 estimated tax payment covers income earned from September through December. The official due date is January 15, but if you underpay throughout the year, the IRS charges a penalty on the shortfall regardless. The safe-harbor target: pay enough to cover 100% of last year's tax liability (110% if your income last year exceeded $150,000), or 90% of this year's actual tax. When the number feels uncertain, overpay slightly — you get the excess back as a refund.

Review every deduction you can still take this year

• Home office: if you use a dedicated space exclusively for work, calculate the square footage now. The simplified method ($5 per square foot, up to 300 sq ft) is fast. The actual expense method — prorating your rent or mortgage, utilities, and internet — can be significantly higher.
• Equipment and software: purchases placed in service before December 31 are deductible this year under Section 179. That computer, monitor, or camera you have been putting off belongs in this year's return if you need it.
• Professional development: courses, books, subscriptions, and conferences related to your work are deductible. Renew annual professional memberships before year-end.
• Health insurance premiums: if you pay for your own coverage and are not eligible for employer coverage through a spouse, your premiums are deductible above the line — meaning they reduce your adjusted gross income, not just your itemized deductions.

Get your books current before December

If you have not reconciled your business accounts since Q2, do it now. The goal is a clean record of every dollar in and out for January through November so you can estimate your year-end position accurately. Waiting until March to do a full-year reconciliation is slower, error-prone, and means you lose the chance to make any adjustments before the year closes.

• Categorize every transaction you have not yet reviewed
• Match invoices sent against payments received — flag any that are still outstanding
• Pull every receipt for expenses you plan to deduct and make sure it is filed somewhere you can find it

Collect W-9s from subcontractors now

If you paid another freelancer or contractor more than $600 for services this year, you are required to file a 1099-NEC for them by January 31. To do that, you need their legal name, address, and taxpayer ID — information that comes from a W-9 form. Requesting a W-9 from someone you stopped working with in June is awkward and slow. Request them now, while the working relationship is fresh.

Consider maxing out retirement contributions

Contributions to a traditional SEP-IRA or Solo 401(k) reduce your taxable income dollar for dollar. The limits are substantial — a SEP-IRA allows up to 25% of net self-employment income — and even a partial contribution can meaningfully reduce your tax bill. SEP-IRA contributions can technically be made up to your tax filing deadline including extensions, but setting funds aside before December 31 prevents the money from being spent before April.

Call your accountant before tax season starts

A 30-minute call with a CPA in November or early December is worth five times the same call in February. In November, there is still time to act on what they tell you. By February, CPAs are in full tax season, turnaround is slower, and most of the moves that could have saved you money are behind a closed door. Bring a rough income estimate, any big purchases you made or are considering, and a list of anything that feels unclear.

None of this replaces personalized tax advice — the right moves depend on your income level, state, and business structure. What this list does is get you organized before the window closes, so March is a matter of filing, not regret.