Year-End Tax Planning 2026: Start With the Numbers, Not the Deadline

Why Year-End Tax Planning 2026 Should Start Before December

Once the year is over, planning turns into reporting. Income, expenses, payroll, and equipment timing are largely set.

Starting earlier gives you time to ask a better question:

Based on how 2026 is actually going, is there anything we should deal with before the year closes?

Here are seven areas I would review.

1. Update Your Profit Forecast Before Making Tax Decisions

Before buying equipment or moving money around for tax reasons, get a fresh look at business income.

Start with your year-to-date profit and loss statement. Then estimate where the rest of the year is heading.

Review revenue, expected income through year-end, payroll, contractor costs, operating expenses, planned purchases, unusual gains or losses, and changes in owner compensation.

A business having a much better year than expected may need a different plan from one that had a slower year.

Too many owners start planning from last year’s return even though this year looks completely different.

Compare this year with last year

Do not assume 2026 looks like 2025.

A large client, higher payroll, tighter margins, or an equipment purchase can move taxable income. Your books do not have to be perfect, but they need to be reliable enough to plan from.

If profit is way up or down, find out why. That change may affect estimated taxes, retirement contributions, depreciation decisions, and cash flow.

IRSProb’s guide to 2026 business tax planning can help frame the broader review.

2. Review Your Estimated Tax Payments

Once you have a reasonable profit estimate, compare it with the estimated tax payments you have already made.

Many owners start with one estimate and never revisit it, even when the year changes.

Estimated tax can apply when enough tax is not being paid through withholding or other payments. Depending on the taxpayer, that may include income tax, self-employment tax, and other taxes.

The IRS provides guidance on estimated tax payments for individuals, sole proprietors, partners, and S corporation shareholders.

Ask yourself:

• Is profit higher or lower than expected?
• Did you receive income you were not planning on?
• Did household withholding change?
• Did you sell investments or other property?
• Have you made the estimated payments you planned?

If income changed during the year, recalculate estimated tax instead of simply repeating last year’s payment pattern.

Another estimated payment or withholding adjustment may be worth discussing with your tax professional. Prior-year tax, current income, withholding, credits, and safe harbor rules may all matter.

Do not guess your way through it. If the numbers changed, run them again.

3. Review Equipment Purchases Before Chasing a Deduction

Equipment is one of the first things people think about when year-end planning comes up.

The conversation often sounds like this:

“I need another deduction. Should I buy something?”

I would turn that around.

First ask whether the business actually needs the equipment. Then look at the tax treatment.

Bonus Depreciation 2026

Current law generally provides 100% additional first-year depreciation for certain qualified property acquired after January 19, 2025, when the placed-in-service and other eligibility rules are met.

Buying something before December 31 does not automatically mean it qualifies for a 2026 depreciation deduction.

Placed-in-service timing matters. The property generally needs to be ready and available for its intended business use when required under the rules.

IRSProb’s guide to Bonus Depreciation 2026 explains more of the timing and eligibility issues.

Section 179 Deduction 2026

Section 179 may also be available for qualifying business property.

For tax years beginning in 2026, the maximum Section 179 deduction is $2.56 million. The deduction begins to phase down when qualifying property placed in service during the year exceeds $4.09 million.

The IRS explains depreciation and Section 179 rules in Publication 946.

Those are headline numbers. Property type, business use, taxable income, and other rules can affect the deduction. Section 179 can also be limited by taxable income from the active conduct of the business.

If the business needs the equipment and the timing makes sense, then the tax treatment deserves a look.

4. Review Retirement Contributions While You Still Have Options

Retirement planning deserves a place in the year-end conversation too.

Depending on the plan and business structure, contributions may help build retirement savings while also creating a tax deduction.

For 2026, the basic employee elective deferral limit for many 401(k) plans is $24,500. The overall defined contribution limit is $72,000 before applicable catch-up contributions.

That does not mean every owner can automatically contribute the maximum.

Compensation, business structure, plan rules, employee eligibility, and contribution type all matter.

SEP Plans

A SEP can be practical for some self-employed people and small businesses.

For 2026, SEP contributions can be subject to a $72,000 maximum, but compensation-based limits and plan rules still apply.

The IRS generally allows a SEP to be established as late as the due date of the business income tax return, including extensions.

You still need to know whether the business has the cash to contribute.

The IRS provides more detail on SEP plans.

Solo 401(k) Plans

A one-participant 401(k), often called a Solo 401(k), may allow an eligible owner to contribute in both employee and employer roles.

The calculation can get more involved for self-employed owners.

A special earned-income calculation may be required. That can involve adjustments for one-half of self-employment tax and the owner’s retirement contribution.

The IRS explains the two-role framework for one-participant 401(k) plans.

Do not look at the employee deferral limit and assume that tells you how much you can contribute.

Different deadlines may apply to employee deferrals, employer contributions, SEP contributions, and plan establishment. Confirm the plan type before relying on a date.

5. Review S Corporation Compensation and Payroll

If you operate through an S corporation and work in the business, year-end is a good time to review how you have been paying yourself.

The IRS generally requires an S corporation to pay reasonable compensation to a shareholder-employee for services provided before treating amounts as nonwage distributions to that shareholder-employee.

There is no magic salary number. Reasonable compensation depends on the work performed, responsibilities, experience, time spent in the business, and comparable pay.

The IRS provides guidance on S corporation compensation and related shareholder-employee issues.

If payroll looks out of line with the work being performed, I would not wait until the return is being prepared to think about it.

Review wages, withholding, benefits, and other payroll items before year-end forms are prepared.

IRSProb’s article on S corporation compliance goes deeper into several of these issues.

Tax preparation reports what happened. Planning gives you a chance to address what is happening now.

6. Clean Up Your Books and Business Records

This may not be exciting, but if the books are wrong, the tax projection can be wrong too.

Make sure business bank accounts and credit cards are reconciled. Look for duplicate transactions, uncategorized expenses, missing income, unexplained transfers, and owner contributions or distributions posted incorrectly.

Do not assume every payment from a business account is deductible without reviewing the business purpose and support.

Review large or unusual expenses. Also check for legitimate business costs paid personally that never made it into the books.

Personal spending mixed into the business account creates more work and confusion. Clean it up.

Keep support for both income and deductions.

Depending on what appears on the return, that may include records for sales, payroll, equipment, mileage, reimbursements, contractor payments, owner transactions, and business expenses.

Receipts, invoices, bank records, payroll reports, mileage logs, and purchase documents may all matter.

The IRS provides general guidance on business recordkeeping.

Good records also tell you what is actually happening in the business.

7. Look at the Full Tax Picture Before Making a Year-End Move

This is where year-end planning often gets too narrow.

One tax move can affect more than one part of the return.

Business income can interact with income tax, self-employment tax, estimated taxes, retirement contributions, depreciation, business credits, and other deductions or limitations.

Exactly how those pieces interact depends on your business structure and personal tax situation.

That is why I would not judge a year-end move by one deduction alone.

Cash flow still matters

A deduction may reduce taxable income. It does not pay your bills.

Before making a large purchase or contribution, think about what the business will need for payroll, rent, debt payments, inventory, insurance, estimated taxes, and early 2027 expenses.

A lower tax bill helps, but running short on cash does not.

Do not buy equipment you do not need. Do not change payroll blindly. Do not move money into a retirement plan without checking what that does to cash flow.

Run the numbers first. Then make the decision.

A Simple Year-End Business Checklist

Before the final weeks of 2026, I would review:

• Your current profit and loss statement
• Expected income and expenses through December
• Estimated tax payments
• Equipment you already plan to purchase
• Bonus depreciation and Section 179 where applicable
• Placed-in-service timing
• Retirement contribution options and deadlines
• S corporation compensation
• Payroll records
• Bank and credit card reconciliations
• Large or unusual expenses
• Supporting tax records
• Cash needs going into 2027
• Major decisions to discuss with your tax professional

You may decide only two or three items need attention. That is fine. Year-end tax planning is about finding what actually fits your business.

What to Do Next

Start with the numbers you already have.

Get the books reasonably current. Estimate where profit is likely to land. Then compare that estimate with what you have already paid in taxes and the decisions still in front of you.

Maybe you need equipment, an estimated tax adjustment, a retirement contribution review, or bookkeeping cleanup. You do not need to manufacture a tax move just because December is coming.

What matters most is knowing where you stand while you still have choices.

If this review turns up a separate problem, such as missed tax payments, IRS notices, or a balance you cannot comfortably pay, deal with that directly.

A new deduction is not a substitute for dealing with an existing IRS issue.

Frequently Asked Questions About Year-End Tax Planning 2026

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