The Colorado capital gains tax calculator combines the correct federal rate for your holding period with Colorado’s flat 4.40% treatment of gains, so you can see your total tax and exactly how much of a gain you keep.
How it works
Colorado treats capital gains as ordinary income, so the state side is always a
flat 4.40%. The federal side depends on how long you held the asset:
- Capital gain = sale proceeds − cost basis.
- Long-term (held over 1 year): federal
0% / 15% / 20%rates apply based on where the gain lands when stacked on your other taxable income. - Short-term (held 1 year or less): the gain is taxed at your ordinary federal marginal rate, found from the 2024 brackets.
- Colorado tax: the gain ×
4.40%, regardless of holding period.
Adding the federal and Colorado amounts gives the total, and the tool reports the combined rate and your net after tax.
Worked example
A single filer sells stock for $50,000 with a $30,000 basis, held long-term,
with $70,000 of other taxable income:
- Gain:
$50,000 − $30,000 = $20,000 - Stacked income
$70,000 + $20,000 = $90,000→ federal long-term rate15% - Federal tax:
$20,000 × 15% = $3,000 - Colorado tax:
$20,000 × 4.40% = $880 - Total:
$3,880, combined rate19.4%, you keep$16,120.
Hold the same position less than a year and the federal portion jumps to your
22% ordinary bracket, raising the total tax sharply.
Notes and tips
- Long-term beats short-term: crossing the one-year mark can drop your federal rate from your ordinary bracket to 15% or even 0%.
- High earners should add the federal 3.8% Net Investment Income Tax, which this calculator does not include.
- The estimate assumes your other income fills the lower brackets; if a large gain spans two federal long-term breakpoints, your blended rate may sit between the single rate shown here.