Table of Contents
- Why Year-End Tax Planning Beats Filing Season Scrambling
- Timing Income and Deductible Business Expenses
- Crypto Tax Loss Harvesting and Capital Gains Review
- Estimated Tax Payment Deadlines and Who Needs to Pay
- Retirement Contributions: Which Deadlines Are December 31
- Business Equipment Depreciation Rules and Section 179
- RMDs, Qualified Charitable Distributions, and Giving Strategies
- S Corporation Reasonable Salary Requirements and Entity Review
- Your Printable Year-End Tax Planning Checklist
- Frequently Asked Questions
Last Updated: October 1, 2026
Why Year-End Tax Planning Beats Filing Season Scrambling
A year-end tax planning checklist is a set of decisions you make before December 31 that change what your return looks like when you file it. Most owners treat tax work as a spring event. By then, the moves that mattered are already locked.
Every item on this checklist falls into one of two buckets: things that must happen by December 31, and things that can wait until you file. Knowing which is which prevents most year-end panic.
Timing Income and Deductible Business Expenses
Timing moves your adjusted gross income without changing your actual economics. In a higher-income year, push deductible expenses in and pull income out to flatten the spike.
Accelerating Deductions, Deferring Income
Cash-basis businesses have real flexibility here. Pay a supplier invoice in December instead of January, stock up on consumable supplies you will use anyway, and consider whether a December invoice can reasonably go out in early January.
- Prepay expenses you would incur within the next few months regardless
- Delay invoicing only where the client relationship and contract allow it
- Bunch discretionary professional spending into the higher-income year
- Do not prepay expenses that belong to a future period just to create a deduction
Crypto Tax Loss Harvesting and Capital Gains Review
Crypto tax loss harvesting means selling positions that have dropped in value to realize capital losses that offset gains elsewhere in your portfolio. Unlike securities, digital assets have different rules regarding wash sales, so confirm current treatment before relying on it. Start with your net realized gain or loss across every account.
Confirming Cost Basis Across Every Wallet and Exchange
Cost basis is what you paid, plus fees, adjusted for every subsequent transaction. If you have traded across multiple exchanges, moved assets between wallets, or used DeFi protocols, your basis records are probably incomplete.
Practical steps before December 31:
- Export full transaction history from every exchange, not just the ones you still use
- Reconcile transfers between your own wallets so they are not counted as sales
- Identify staking, airdrop, and mining income separately, since those are ordinary income at receipt
- Match every disposal to a specific acquisition lot
If you cannot document basis for an asset, the default treatment can result in a larger taxable gain than you actually had. Reconstructing basis after the fact is far harder than exporting it now.
Estimated Tax Payment Deadlines and Who Needs to Pay
Estimated tax payments are due quarterly, and the final one lands in mid-January, so your fourth-quarter payment is made after the calendar year ends but before you file. You generally need to make estimated payments if you expect to owe tax beyond what was withheld. That usually includes self-employed people, freelancers, investors with realized gains, landlords, and anyone receiving crypto income. See the IRS estimated tax FAQ for details.
Retirement Contributions: Which Deadlines Are December 31
The deadline depends on the account type. Two dates matter: December 31, a hard cutoff for establishing and electing certain accounts, and the filing deadline, when funding can still happen for others.
| Account Type | Deadline | Who It Suits |
|---|---|---|
| Solo 401(k) employee deferral | December 31 (election) | Self-employed with no employees |
| Solo 401(k) employer contribution | Filing deadline, extensions included | Same, if cash flow is uncertain |
| SEP IRA | Filing deadline, extensions included | Owners wanting simplicity |
| Traditional IRA | Filing deadline | Anyone with earned income |
| Roth IRA | Filing deadline | Those under the income phase-out |
What Actually Has to Happen by December 31
For a Solo 401(k), the timing depends on how your business is set up. If you are a sole proprietor or single-member LLC with no employees, you can establish a new plan after year-end, up to your filing deadline without extensions, and still make employee deferrals for that first year. In later years, the deferral election should be made by December 31. If you are an S corporation owner, employee deferrals come out of your W-2 wages, so they must run through payroll by December 31. The employer contribution can wait until the filing deadline, including extensions.
The Trade-Off You Are Actually Choosing
Every retirement decision here is a trade between a current-year deduction and future tax treatment. Traditional contributions reduce taxable income now and are taxed on withdrawal. Roth contributions give no current deduction but grow and come out tax-free if qualified rules are met. In a low-income year a Roth can be more valuable; in a high-income year the deduction usually is.
Practical Steps Before December 31
- Decide which accounts you are using and confirm whether each has a December 31 establishment or election deadline
- Open any Solo 401(k) you plan to use, even if you will fund it later
- Check the current-year limit before calculating a contribution, the limit changes and the catch-up rules differ by account
- Confirm whether your income puts you near a Roth phase-out
- Coordinate contributions with your projected adjusted gross income so you are not choosing a deduction you cannot use
S corporation owners: if you plan to defer salary into a Solo 401(k) this year, set up the plan and payroll withholding before your final December payroll runs. That is the step that cannot wait.
Business Equipment Depreciation Rules and Section 179
Business equipment depreciation rules let you recover the cost of qualifying property over time, but Section 179 and bonus depreciation let you accelerate that recovery. Limits, phase-outs, and bonus percentages change, so check the current-year figures before relying on either.
How the Two Provisions Differ
Section 179 lets you elect to deduct the full cost of qualifying property in the year it is placed in service, up to an annual limit, with a phase-out above a purchase threshold. It is an election, and it has a taxable income limitation, you cannot use it to create or increase a business loss. Bonus depreciation allows an additional first-year deduction without the same election mechanics or income limitation, but the bonus percentage changes over time, so confirm the current-year rate.
What Qualifies and What Does Not
- Tangible personal property used in the business generally qualifies for both
- Used property can qualify for Section 179 in many cases, but bonus depreciation rules on used property differ
- Vehicles and property used partly for personal purposes have limits and separate rules
- Real property generally does not qualify for bonus depreciation, though certain improvements may
- Property used to generate rental income may or may not qualify depending on the facts
The Placed-in-Service Rule
The asset must be placed in service before December 31, not merely ordered or paid for. This is the single most common year-end mistake. An invoice dated December 28 with delivery in February does not help this year.
When Electing Out Makes Sense
Skipping Section 179 or electing out of bonus depreciation is sometimes better. If you expect significantly higher income in future years, spreading the deduction over time can be more valuable than taking it all now, and the same applies if you are near a phase-out or credit threshold a large current-year deduction would push you past.
Practical Steps Before December 31
- Confirm any planned purchase will be placed in service before December 31, not just ordered
- Identify which assets qualify for bonus depreciation versus Section 179
- Check the current-year limit and phase-out before assuming a full deduction
- Decide whether electing out fits your income trajectory
- Keep documentation of the placed-in-service date, cost, and business use percentage for every asset
A deduction taken in the wrong year is harder to fix than one you defer. If the placed-in-service date is close to December 31, document it clearly.
RMDs, Qualified Charitable Distributions, and Giving Strategies
Required minimum distributions are mandatory withdrawals from traditional IRAs and most employer retirement plans once you reach the applicable age. Missing one triggers a penalty. Your first RMD can be delayed until April 1 of the following year, but every later RMD is due by December 31. Check the current rules for your account type and age.
If you are age 70½ or older and give to charity, a qualified charitable distribution lets you send money directly from your IRA to a qualified charity, up to an annual limit. The amount counts toward your RMD and is left out of your taxable income, which helps even if you take the standard deduction. The transfer must go directly from the IRA custodian to the charity.
If you give to charity but do not qualify for a QCD, ask two questions before December 31:
- Would bunching two years of gifts into one year push your itemized deductions above the standard deduction?
- Would donating appreciated assets you have held more than a year avoid capital gains while still generating a deduction?
S Corporation Reasonable Salary Requirements and Entity Review
S corporation reasonable salary requirements mean the owner-employee must be paid wages that reflect what the work would cost to hire. The remaining profit passes through as distributions, which are not subject to payroll tax. Setting salary too low is a frequent focus of IRS review for S corps.
Ask three questions:
- Is your current salary defensible against what a comparable role pays?
- Has your revenue grown enough that a different entity structure would now save more than it costs to maintain?
- Are your draws and distributions recorded separately from payroll?
Your Printable Year-End Tax Planning Checklist
Work through this in order. Each item covers a decision that actually changes your return.
Income and expenses
- Project your full-year adjusted gross income using actuals, not estimates
- Decide whether to accelerate expenses or defer income based on that projection
- Confirm any prepaid expense belongs to this period
Capital gains and crypto
- Calculate net realized gains and losses across all accounts
- Export transaction history from every exchange
- Reconcile wallet-to-wallet transfers so they are not treated as disposals
- Confirm cost basis for every asset you may sell
- Identify staking, airdrop, and mining income separately
Estimated taxes
- Recalculate projected liability with year-to-date numbers
- Adjust the January payment if income came in higher than planned
Retirement
- Confirm which accounts have a December 31 deadline
- S corporation owners: set up any Solo 401(k) and payroll deferrals before the final December payroll
- Check the current-year contribution limit before calculating
Equipment and depreciation
- Confirm any planned purchase will be placed in service before December 31
- Decide whether Section 179 or bonus depreciation fits this year
Distributions and giving
- Take any required minimum distribution before December 31
- Evaluate qualified charitable distributions if you qualify
- Consider bunching gifts or donating appreciated assets
Entity and records
- Review S corporation salary against comparable market wages
- Separate draws from payroll in your records
- Reconcile bookkeeping through the most recent month
- Gather W-2s, 1099s, K-1s, and Form 1099-DA for crypto activity
- Note any life changes: marriage, a new dependent, a move, a new business
Print this and mark the items that require a decision rather than a document. The decision items are the ones with a December 31 deadline. The document items can wait until January.
Frequently Asked Questions
What should be included in a year-end tax planning checklist?
A solid year-end tax planning checklist covers timing income and deductible expenses, reviewing capital gains and losses, confirming cost basis for every crypto wallet and exchange, and checking whether your estimated tax payments cover what you owe. It should also include retirement contributions, business equipment purchases, required minimum distributions, charitable giving, and an entity review if you operate as an S corporation. Finish by reconciling your bookkeeping and gathering income forms so filing season runs smoothly. Check the current-year limit on any deduction or contribution before you act.
What is crypto tax loss harvesting and how does it work?
Crypto tax loss harvesting means selling digital assets that have dropped in value to realize a capital loss, which can offset capital gains elsewhere in your portfolio. The key requirement is confirming cost basis for every wallet and exchange before you sell, since missing basis records can make a loss look like a gain. Losses beyond what gains absorb may offset ordinary income up to the current-year limit, with the rest carrying forward. Keep exchange statements and on-chain records together so the reporting holds up.
When are estimated tax payment deadlines for self-employed people?
Estimated tax payments run on a quarterly schedule, with the final payment typically due in mid-January of the following year. Self-employed people, investors, and anyone with non-wage or crypto income generally need to pay as they earn rather than waiting until filing season. If your income jumped late in the year, a fourth-quarter payment can reduce the shortfall. Review your year-to-date profit and withholding before the deadline, and check the current-year dates since they shift slightly when a due date lands on a weekend or holiday.
How do S corporation reasonable salary requirements affect year-end planning?
If you own an S corporation and work in the business, the IRS expects you to take a reasonable salary through payroll before year-end. Distributions alone do not satisfy that requirement. Reasonable salary depends on your role, the hours you work, your industry, and what comparable businesses pay, so it is worth reviewing before December 31 rather than after. Underpaying payroll can create problems with employment taxes, while overpaying reduces the benefit of the S election. A year-end review keeps payroll, draws, and distributions aligned.