Quarterly Tax Planner for Self-Employed Income

You've been freelancing for eight months. Clients have paid you $62,000 so far, and you haven't sent the IRS a dime. Now it's September, you just realized quarterly payments are a thing, and you're wondering how badly you've messed up.

Or maybe you've been making payments, but you guessed the amounts and you have no idea if you're overpaying, underpaying, or somewhere in the ballpark. The IRS will tell you in April—along with a penalty notice if you got it wrong.

This planner calculates exactly what you should be paying each quarter based on your actual profit, shows you how to catch up if you're behind, and helps you avoid the underpayment penalties that catch so many self-employed people off guard.

• Net profit, not revenue: You're taxed on profit after expenses, not gross receipts. A $100,000 year with $35,000 in expenses means quarterly payments based on $65,000—not $100,000. Track expenses monthly.
• Self-employment tax (15.3%): This is on top of income tax. Social Security (12.4% up to $176,100) plus Medicare (2.9% uncapped). New freelancers who only budget for income tax get blindsided by this extra 15.3%.
• W-2 withholding credit: If you have a day job, your W-2 withholding counts toward your total tax obligation. High enough W-2 withholding might cover your self-employment tax entirely—meaning $0 quarterly payments needed.
• Safe harbor rules: Pay 100% of last year's total tax (110% if AGI over $150,000) and you avoid penalties regardless of what you actually owe. If your income is rising fast, this is the simplest approach.
• Retirement contributions: SEP-IRA or Solo 401(k) contributions reduce your taxable income and thus your quarterly payments. A $15,000 SEP contribution can cut your payment by $3,000-$5,000 for the year.

Example 1: Dana Pays Quarterly From Day One

Dana quits her marketing job in January to freelance full-time. She projects $85,000 in net profit for the year and sets up quarterly payments immediately.

Dana pays $5,550 on April 15, June 15, September 15, and January 15. Her actual profit ends up at $91,000, so she owes about $1,800 more when she files—but no penalties because she paid throughout the year.

Example 2: Marcus Catches Up in Q3

Marcus has been freelancing since January but didn't make any quarterly payments. It's now September, he's earned $58,000 in profit, and he just realized he's in trouble.

Marcus will face some underpayment penalties for Q1 and Q2, but by catching up now he minimizes the damage. If he waits until April to pay everything, the penalties compound for the full year.

• Forgetting the 15.3%: New freelancers budget 22-25% for income tax and forget self-employment tax exists. That's another 15.3% on top. Budget 35-40% of profit for total federal taxes.
• Using revenue instead of profit: If you bill $120,000 but spend $40,000 on expenses, you owe tax on $80,000. Calculate payments on net profit, not gross revenue.
• Ignoring the uneven quarters: Q2 is only 2 months (April-May). Q3 is 3 months (June-August). Income from June goes toward your Q3 payment, not Q2.
• Spending the tax money: A $15,000 client payment isn't $15,000 for you—it's about $10,000 after taxes. Transfer 30-35% to a separate tax account immediately.
• Skipping state payments: Most states with income tax also require quarterly estimated payments. California, New York, and others will charge their own penalties if you don't pay.

If a deadline falls on a weekend or holiday, the due date moves to the next business day. Pay via IRS Direct Pay (free, instant) or EFTPS (requires enrollment in advance).

We take your projected net profit, calculate self-employment tax, estimate income tax based on your bracket, and divide by four quarters (or remaining quarters if you're catching up).

What we include: Federal self-employment tax, federal income tax estimate, W-2 withholding offset.

What we don't include: State estimated taxes (calculate separately), QBI deduction, SEP/401(k) contributions, or specific tax credits. This gives you a baseline—adjust upward if you want a cushion or downward if you have significant deductions.