How I Track Quarterly Tax Payments as a Freelance Developer

The first year I went full-time freelance writing software, my taxes blew up. I had no W-2 withholding. I had no system. I paid the bill in April and then a few weeks later opened an IRS letter with the words "underpayment penalty" on it. The amount was small (about $340) but the message was clear: pay quarterly or pay extra.

After two years of refining the workflow, here is the system I use now. Nothing fancy, no expensive accounting software. Just a few clear rules and one calculator I run quarterly.

Photo by Hook Tell on Pexels

The Underlying Problem

A freelancer's tax obligation breaks into three parts:

1. Federal income tax (based on bracket)
2. Self-employment tax (15.3% on the first $168,600 of net earnings in 2026)
3. State income tax (varies wildly by state)

W-2 employees pay these through automatic payroll withholding. Freelancers do not have that, so the IRS expects four quarterly installments instead. Skip the installments and the underpayment penalty kicks in, even if you pay everything by April 15th. The deeper mechanics of the penalty and the "safe harbor" rule that prevents it are covered well in this guide on freelancer underpayment penalties if you want the full picture.

This is what my system handles.

The Three Accounts

I run everything through three accounts:

• Business checking (Mercury): all client payments come in here
• Personal checking (traditional bank): my "paycheck" lands here on a fixed schedule
• Tax reserve (high-yield savings at Ally): the IRS's money, sitting there waiting

The flow: client payment lands in business checking, I immediately transfer 30 percent to the tax reserve, then move a fixed monthly amount to personal checking as my "salary." Anything left in business checking is operating cushion for slow months.

The 30 percent reserve covers federal income tax, SE tax, and California state tax for my bracket. If you live in a no-tax state like Texas or Florida, 22 to 25 percent is enough.

The Spreadsheet

I track three columns in a spreadsheet that gets updated weekly:

Date         | Client            | Amount      | Reserve transfer
2026-01-04   | Client A          | $4,500      | $1,350
2026-01-12   | Client B          | $2,800      | $840
2026-01-19   | Client A          | $4,500      | $1,350

That is it. Four columns. No category coding, no project codes (those live in my time-tracking tool). The reserve transfer column is always exactly 30 percent of the amount column. I sum the reserve column quarterly and that gives me a sanity check against what I actually paid the IRS.

Tools that automate this: Wave for free invoicing-plus-bookkeeping, QuickBooks Solopreneur for $20/month, or just a Google Sheet for $0. I used a sheet for two years before I had enough complexity to justify Wave.

The Quarterly Run

Once a quarter, two weeks before the deadline, I do a 20-minute review:

1. Open the Quarterly Tax Estimator and enter year-to-date income, deductions, filing status, and state.
2. Compare the suggested quarterly payment to what I have already paid for the year.
3. Decide whether this quarter's payment should match the suggestion or adjust higher/lower based on the trailing income trend.
4. Pay through IRS Direct Pay (federal) and the California EDD portal (state).
5. Save both confirmation numbers in a Notion page tagged with the year and quarter.

The whole loop is roughly 20 minutes if my records are clean. Twice it has taken an hour because I needed to reconcile a client payment that arrived from a third-party payment processor with a different routing number than the rest. That is what the bookkeeping is for.

The Federal Payment

For federal estimated taxes, IRS Direct Pay is the simplest option. No account setup, no fees, just bank routing and account number, plus the year and quarter the payment applies to. It clears in two business days and you get an email confirmation.

If you prefer scheduling payments months in advance, EFTPS is the Treasury's older system. Setup takes about a week because they snail-mail you an activation PIN, but once enrolled you can schedule all four installments at the start of the year.

I use Direct Pay because I like adjusting each quarter based on actual income, not predicting January numbers in December.

The State Payment

State systems vary by state. In California I pay through the Franchise Tax Board's web portal. In Texas there is no quarterly state estimate at all because there is no state income tax. New York has its own scheduler. The best resource for your state is your state's Department of Revenue or equivalent agency.

The deadlines mostly align with federal (April 15, June 15, September 15, January 15), but a few states use slightly different dates. Always check.

What I Wish I Had Known in Year One

A few things would have saved me significant pain if I had known them earlier:

Year-one estimates are guesses. Without a prior-year return to base the safe harbor on, you are using the 90% current-year rule, which requires forecasting income that has not happened yet. Overshoot the estimate slightly. The penalty for paying too much is zero (you get the refund), and the penalty for paying too little is real money.

Self-employment tax is not optional and not deferrable. SE tax is the freelancer's contribution to Social Security and Medicare. It is the 15.3 percent that surprises new freelancers, and it sits on top of federal income tax. Half of it is deductible against income tax, but the SE tax itself still has to be paid quarterly.

The state side matters as much as the federal side. A California freelancer with $80,000 of net income owes roughly $4,500 in state tax on top of federal. Missing California's quarterly deadline produces its own penalty separate from federal.

Health insurance premiums are deductible. If you pay your own health insurance as a self-employed person, the premiums are deductible above the line. This was worth about $4,000 in tax savings for me last year and I almost missed it.

The 30-Second Pitch For Whoever Is Reading This Mid-Panic

If you are reading this two weeks before April 15th in your first year freelancing and you have not paid any quarterly taxes:

1. Calculate your full-year federal tax liability using a tool like EvvyTools' quarterly calculator.
2. Pay the entire annual amount through IRS Direct Pay right now, this week.
3. Yes, you will probably owe an underpayment penalty for the earlier quarters, but it caps. Paying late is cheaper than not paying.
4. Build the four-account system above for next year so this does not happen twice.

Most freelancers experience the penalty exactly once. It is the kind of mistake that fixes itself the moment you see how the rule works. The full breakdown of the safe harbor mechanics goes deeper into why the IRS structured it this way and how to make sure year two is penalty-free.

The system above takes about an hour to set up and runs in the background for the rest of your freelance career.