How Much Should I Set Aside for Quarterly Estimated Taxes?

The Short Answer

There's no single percentage that fits every business owner. A common shortcut is to set aside a flat 25–30% of net profit, and that's not a bad starting point — we cover it in our quarterly estimated tax checklist. But it can be too high or too low depending on your total income, your deductions, your filing status, and whether self-employment tax applies. The real number comes from your actual situation, not a rule of thumb applied blindly.

Why a Fixed Percentage Doesn't Work for Everyone

A flat percentage assumes every dollar of business profit is taxed the same way for every person, which isn't true. Someone with a working spouse and significant household income is already in a different tax position than someone whose business income is their only income. Someone who maximizes retirement contributions and business deductions may owe meaningfully less than someone who doesn't. The percentage that worked for a friend's business or a number quoted online isn't automatically the right one for yours.

What Actually Affects the Amount

Business Income

Your net business profit — not gross revenue — is the starting point. Two businesses with the same revenue can owe very different amounts depending on their expenses.

Other Income

Income from a spouse's job, investments, rental property, or a side business all add to your total taxable income and can push you into a different situation than your business income alone would suggest.

Deductions

Business expenses reduce your taxable business income. Retirement contributions, the standard deduction or itemized deductions, and other adjustments reduce it further. More deductions generally mean less needs to be set aside — but only if they're tracked and claimed correctly.

Filing Status

Married filing jointly, single, or head of household all use different tax brackets and different standard deduction amounts, which changes how much of your income is actually taxed at each rate.

Self-Employment Tax, Where Applicable

If you're a sole proprietor or a single-member LLC taxed as a disregarded entity, your net business profit is generally subject to self-employment tax in addition to income tax. That's a separate calculation from your income tax bracket, and it's often the piece people forget when they estimate using income tax rates alone. This is also part of why the S-Corp question comes up so often — see our comparison of S-Corp vs. LLC tax treatment for how entity structure affects this.

Prior-Year Tax Liability

Many taxpayers use last year's total tax liability as a benchmark for this year's estimated payments, since it's a known number rather than a projection. Whether that approach works well for you depends on how much your income has changed since then.

Changes in Income During the Year

A percentage set in January doesn't account for a strong third quarter or a slow fourth. Estimated payments are supposed to be revisited as the year goes on, not calculated once and left alone.

A Practical Example

Consider a self-employed consultant who expects roughly $80,000 in net business profit this year, is married filing jointly, and has an additional $20,000 in household income from a spouse's job. Last year, their net profit was closer to $60,000.

To estimate what to set aside, the relevant factors are: total household taxable income after deductions (business profit plus other income, minus the standard or itemized deduction), the income tax owed at the applicable rates for their filing status, and self-employment tax on the net business profit. Some taxpayers instead use last year's total tax liability as a simpler benchmark, adjusted upward if this year's income is clearly higher. Either approach requires current tax rates and the household's full picture — which is exactly why this example stops short of a dollar figure. The point isn't the number; it's that business income, household income, deductions, and self-employment tax all feed into it together.

Why Tax Planning Throughout the Year Helps

Estimated taxes work better as an ongoing conversation than a once-a-year guess. Reviewing income and the amount set aside each quarter — not just in January — catches a strong or slow stretch before it turns into a large payment or a large penalty at filing time.

When Professional Help Makes Sense

A few situations usually mean it's worth having someone calculate this with you rather than estimating alone:

• Your first year of self-employment, when there's no prior-year number to work from
• Income that varies significantly from quarter to quarter
• More than one source of income feeding into the same return
• An entity structure decision — like an S-Corp election — that changes how self-employment tax applies

How Carlos Veras CPA PA Can Help

Quarterly estimated tax calculations are part of our tax preparation and planning service — we calculate the number based on your actual business and household income, not a flat percentage, and revisit it as your year changes.