The 2026 401k contribution limit is $23,500 ($31,000 if you are 50+). In Colorado, pre-tax contributions reduce your taxable income at both federal (22%–37%) and CO state (4.4% flat) levels. Annual tax savings on a full contribution: $6,204.
Colorado taxes 401k and traditional IRA distributions as ordinary income at up to 4.4%. On a $82,200/year retirement income, that is $3,617 per year in state tax. Consider Roth 401k contributions if you expect to retire in CO and your future bracket is similar to today.
Colorado also taxes Social Security benefits. High 401k withdrawal amounts can push your provisional income above thresholds that trigger Social Security taxation at the state level. Roth conversions before RMD age can reduce this risk.