When you were a W-2 employee, taxes came out of every paycheck automatically. When you’re self-employed, no one does that for you, so the IRS asks you to pay as you go in four estimated installments across the year. Miss them and you can owe a penalty even if you pay in full by April. The good news: estimating is only hard when your books are a mystery. With current numbers, sizing each payment takes a few minutes. Here’s who owes, when it’s due, and how to hit a number you can trust.
Educational overview, not tax advice. Due dates shift when they fall on weekends or holidays, and safe-harbor percentages and thresholds change, so confirm the current specifics at irs.gov and let your CPA set your actual payments. What clean books give you is an accurate starting number to bring them.
Who has to pay estimated taxes?
Generally, if you expect to owe about $1,000 or more when you file, and you don’t have enough withheld from another source, you’re expected to make quarterly payments. That sweeps in most freelancers, contractors, single-member LLC owners, and side-hustlers whose side income isn’t covered by a day-job’s withholding. If your work is on Schedule C, this almost certainly applies to you.
Why quarterly? Because the tax system is pay-as-you-go. Employees satisfy that through paycheck withholding; the self-employed satisfy it through estimated payments. New to running your own books? Bookkeeping for freelancers is the place to start.
The four due dates
The year is split into four (uneven) payment periods. Roughly:
| Payment | Covers income from | Due around |
|---|---|---|
| Q1 | January – March | Mid-April |
| Q2 | April – May | Mid-June |
| Q3 | June – August | Mid-September |
| Q4 | September – December | Mid-January (next year) |
Note the periods aren’t even three-month blocks, and the exact dates move a day or two when they land on a weekend or holiday. Check irs.gov for the current year’s calendar and mark all four.
Safe harbor: the rule that keeps you penalty-free
You don’t have to predict your final tax perfectly. The IRS offers a safe harbor: pay enough during the year and no underpayment penalty applies, even if you owe more at filing. You’re generally safe if you pay the smaller of:
- 90% of this year’s total tax, or
- 100% of last year’s total tax (rising to 110% if your income was above a higher-income threshold).
The last-year figure is powerful because it’s a known number: take what you owed last year, divide by four, and you have a floor that keeps you penalty-safe while your income grows. Your CPA will pick the method that fits your year.
How to estimate your payment
Here’s the mental model. Start with your business net profit (income minus deductible expenses), then stack two taxes on it:
- Self-employment tax of about 15.3% on your net profit (Social Security and Medicare, the part an employer used to split with you).
- Income tax at your marginal bracket, which depends on your total household income.
A rough working rule many freelancers use is to set aside somewhere around 25% to 30% of net profit for federal taxes, then adjust for your state and bracket. That’s a starting point, not a promise; your real number comes from your actual profit and your CPA’s read on your bracket. Every deduction you capture (see small business tax deductions) lowers net profit and, therefore, the payment.
The set-aside habit that makes this painless
The people who dread estimated taxes are the ones who spend the whole payment before it’s due. The fix is a habit, not willpower: the moment a client payment lands, move a fixed percentage (say 25% to 30%) into a separate savings account you don’t touch. When the quarterly date arrives, the money is already there and the payment is a transfer, not a scramble.
This is far easier when your business money is separate from your personal money in the first place. If it isn’t yet, fix that first: separating business and personal finances is the foundation the whole habit rests on.
Size each payment from your live numbers
The reason estimates go wrong is stale books: you’re guessing at profit because nobody’s categorized the last three months. Keep the books current and each quarter you can pull an accurate profit figure on demand and size the payment off real data instead of a hunch.
LedgerMCP’s financial reports let you run a profit and loss statement for any period, any time, so a week before each due date you can see exactly what you earned and set the payment from it. Ask your connected assistant or run it yourself in the web app:
"Run my P&L for this quarter so I can size my estimated payment." → Net profit, Apr 1 – Jun 30: $31,400 → Taxable base (92.35% of net): $28,998 → ~15.3% self-employment tax: ≈ $4,437 → Plus income tax at your bracket (confirm with your CPA)
A number grounded in your actual quarter beats a guess every time, and it keeps you comfortably inside the safe harbor. Pair it with a running profit and loss statement so nothing surprises you.
Quick answers
What happens if I underpay?
The IRS can charge an underpayment penalty, essentially interest on what you should have paid each period. Meet a safe harbor (90% of this year or 100/110% of last year) and you generally avoid it even if you owe more at filing.
Do I still pay if the business had a loss?
If you truly had no net profit and expect no tax, there may be nothing to pay for that period, but check your whole picture (a spouse’s income, other earnings). When in doubt, run the numbers and ask your CPA rather than skipping a payment on assumption.
How do I actually set the money aside?
Open a separate savings account and move a fixed percentage of every payment into it the day it arrives. Treat that account as untouchable. When the quarterly date comes, you’re just transferring money you already parked.
I have a W-2 job and a side income. Do I owe estimates?
Maybe not, if you bump up the withholding at your day job to cover the side income’s tax. Extra paycheck withholding counts as paid evenly through the year, which can be simpler than four separate payments. Your CPA can help you dial in the W-4.