Quarterly tax math in District of Columbia runs on two parallel tracks — federal (IRS) and state (DC Office of Tax and Revenue). District of Columbia taxes income progressively up to 10.75%. Underpaying either track triggers a separate penalty that accrues by the day.
District of Columbia uses a progressive bracket system on top of federal tax. For single filers in 2026:
| Income (single filer) | Marginal rate |
|---|---|
| $0 – $10,000 | 4.00% |
| $10,000 – $40,000 | 6.00% |
| $40,000 – $60,000 | 6.50% |
| $60,000 – $250,000 | 8.50% |
| $250,000 – $500,000 | 9.25% |
| $500,000 – $1,000,000 | 9.75% |
| $1,000,000+ | 10.75% |
Federal estimated tax due dates (April 15, June 15, September 15, 2026, and January 15, 2027) apply to your District of Columbia state estimated payments as well — most states piggyback on the federal schedule. Pay District of Columbia taxes through the DC Office of Tax and Revenue's online portal: mytax.dc.gov. You can also mail Form D-40ES with a check.
Federal and state estimated tax safe harbors work in parallel for District of Columbia freelancers. Hit the federal safe harbor (90% of current-year federal tax OR 100% of prior-year federal tax — 110% if your prior-year AGI exceeded $150,000) and you avoid the IRS underpayment penalty on Form 2210.
For District of Columbia state estimated taxes, most filers can match the federal safe harbor approach by paying 100% of last year's District of Columbia tax in four equal quarterly installments. District of Columbia's underpayment penalty is calculated on the state's equivalent of Form 2210 — the OTR can assess interest plus a flat penalty on the under-paid amount.
Practical advice for District of Columbia self-employed taxpayers: pay both federal and state estimates on the same quarterly schedule (April 15, June 15, September 15, January 15). File your federal payment via IRS Direct Pay and your state payment via MyTax.DC.gov. Keep records of every payment — both agencies can request proof if the safe-harbor math is challenged later.
Four procedural details about District of Columbia estimated taxes that catch first-time filers:
DC charges an 8.25% Unincorporated Business Franchise Tax (Form D-30) on net business income over $12,000 from DC sources — this is on top of personal income tax. Most sole proprietors and single-member LLCs with DC clients owe both. The $12,000 exemption is per business, not per person, and the 'salary allowance' deduction (currently $5,000) can lower the taxable base. DC's top personal income rate of 10.75% on income over $1M is among the highest in the country.
Five District of Columbia-specific or broadly-applicable mistakes that consistently cost self-employed taxpayers money: