How to use this calculator
- Enter the inputs using consistent units.
- Review rate, timing, and scope assumptions.
- Select Calculate to update every result.
- Change one assumption at a time to compare scenarios.
#3308 · Finance Tool
Tax Loss Harvesting Tax Impact Calculator
Estimate the immediate and deferred tax effects of harvesting an investment loss. Compare current tax savings with the future tax created by a lower replacement basis, then see the net present value of the tax timing difference.
Calculator
Enter assumptionsFormula
Net present tax impact = loss × current rate − [loss × future rate ÷ (1 + discount rate)years] − cost
What the result means
The result values tax timing only. It does not include reinvestment returns, replacement-security tracking difference, carryforward expiration, or wash-sale disallowance.
This is an educational estimate, not tax, legal, or investment advice. Tax rules, eligibility, account ordering, and state treatment vary; confirm decisions with a qualified professional.
Example calculation
A $15,000 loss at 35% saves $5,250 now. Future tax at 20% is $3,000; discounted 8 years at 5%, it is $2,030.52. After $75 cost, net present tax impact is $3,144.48.
Tips for better results
- Keep units consistent from input through result.
- Use unrounded values during the calculation and round only the displayed result.
- Run a conservative and an optimistic scenario before acting.
- Document assumptions so the estimate can be reproduced.
Frequently asked questions
Why is future tax discounted?
A dollar paid later generally has a lower present value than a dollar paid today.
Does the calculator assume the full loss is usable now?
Yes. Reduce the loss or current rate if use is delayed or limited.
Is reinvestment growth included?
No. This calculator isolates tax impact; use the after-tax value calculator for a growth scenario.
What does a negative net tax impact mean?
Under the entered assumptions, future tax present value and costs exceed current savings.
Does this calculate wash-sale disallowance?
No. It assumes the harvested loss remains allowable.
Related calculators
Tax impact timeline
| Time | Modeled cash effect |
|---|---|
| Today | Current tax savings less implementation cost |
| Future sale | Tax on the basis difference |
| Present value | Future tax discounted to today |