A Mechanical Engineer earning $90K/year in South Dakota takes home $72,090 after all taxes. That’s $6,008/month, with an effective tax rate of 19.9%.
The estimated median salary for Mechanical Engineers in South Dakota is $85K (adjusted from the national median of $92K using South Dakota’s cost-of-living index of 92). At $90K, you’re earning 6% above the state-adjusted median for this profession.
You’re earning above the median, suggesting you’ve moved beyond entry-level. As your career progresses, each raise will be taxed at your marginal rate, so understanding your bracket position helps you evaluate the true value of promotions and raises.
Filing as married filing jointly on $90K (single earner) saves you $4,585/year ($382/month) compared to filing single. This marriage bonus comes from the doubled standard deduction ($32,200 vs $16,100) and wider lower brackets.
Mechanical engineers who hold a Professional Engineer (PE) license can deduct licensing and continuing education costs if self-employed. Patent bonuses or invention awards from your employer are taxed as ordinary income. Engineers who travel to job sites or manufacturing facilities should track mileage if self-employed — the 2026 standard mileage rate can add up to significant deductions. If you receive a signing bonus when changing employers, it’s withheld at the 22% supplemental rate regardless of your actual bracket.
At #5 out of 50 states for take-home pay on a $90K salary, South Dakota is among the best states for keeping your paycheck. You’d keep $0 more per year in Alaska (#1), or $0/month.
After adjusting for cost of living, South Dakota ranks #6 in purchasing power. That’s a drop from #5 in raw take-home — South Dakota’s higher cost of living erodes some of your advantage.