District of Columbia levies a 8.95% state income tax, which applies on top of your federal tax obligations. This creates a combined marginal rate that directly reduces your take-home pay and affects retirement contribution decisions. The cost of living index in District of Columbia is 137, so your after-tax dollars buy less than average due to higher living costs. Use this calculator to estimate your total District of Columbia income tax liability for 2026, including applicable deductions and credits.