The IRS expects you to pay taxes as you earn income, not in one lump sum in April. For business owners with steady income, that’s straightforward. When your income bounces around from month to month or season to season, it gets more complicated. But there are a few approaches that keep you out of trouble.

The simplest method is the safe harbor rule. If you pay at least 100% of last year’s total tax liability in four equal quarterly installments, the IRS won’t charge underpayment penalties regardless of how much you actually earn this year. If your adjusted gross income was over $150,000 last year, that threshold bumps to 110%. So if you owed $20,000 in total tax last year and your AGI was under $150K, paying $5,000 each quarter covers you even if this year’s income doubles.

The downside of the safe harbor approach is that it can tie up cash you might need in the business. If last year was great but this year is slow, writing those quarterly checks can hurt. That’s where the annualized income installment method comes in. This lets you calculate your estimated tax based on income actually received during each period rather than dividing the year into equal quarters. You report this on IRS Form 2210 Schedule AI when you file your return. It requires more detailed tracking throughout the year, but it means you’re not overpaying in slow quarters.

A practical approach many business owners use is setting aside a fixed percentage of every deposit into a separate tax savings account. Something in the range of 25% to 30% works for most self-employed individuals in Texas, where you’re only dealing with federal income tax and self-employment tax. This creates a buffer so you always have funds available when quarterly due dates come around on April 15, June 15, September 15, and January 15.

Review your situation at the midpoint of the year. If Q1 and Q2 were significantly better or worse than expected, adjust your Q3 and Q4 payments. You’re allowed to make unequal payments as long as you meet one of the safe harbor thresholds or accurately estimate current-year tax. Waiting until the end of the year to catch up usually means a penalty on the earlier quarters you underpaid.

Working with a bookkeeper in Pearland who keeps your books current throughout the year makes all of this easier. You can’t estimate taxes accurately if you don’t know your actual profit. If your books are three months behind, your estimated payments are just guesses.

For business owners with income that swings dramatically, quarterly check-ins with someone who handles personal tax returns can prevent surprises. They can run projections based on year-to-date numbers and adjust your remaining payments so you’re not scrambling in April. The goal is paying enough to avoid penalties without sending the IRS money you need to operate.