Does the wash sale rule only apply to repurchasing the EXACT same stock?

No - it also applies to "substantially identical" securities, a genuinely gray area that can include things like different share classes of the same company or, in some interpretations, very similar ETFs tracking nearly identical indexes - this requires careful judgment or professional guidance for borderline cases.

What actually happens if I trigger a wash sale?

The disallowed loss doesn't just disappear - it's added to the cost basis of the newly purchased shares, effectively deferring the loss until you eventually sell those new shares (assuming no further wash sale) - it's a timing rule, not a permanent loss of the tax benefit.

Does the wash sale rule apply to gains too, or just losses?

Only losses - there's no such thing as a "wash sale" restriction on claiming gains; the rule specifically exists to prevent investors from claiming tax losses while maintaining essentially the same investment position.

How should I read the Wash Sale Rule Calculator result?

Read the primary answer first, then review the supporting values, formula notes, assumptions, and expert suggestions. The supporting values explain why the answer moved and which inputs deserve more attention.

Which input matters most in the Wash Sale Rule Calculator?

The most important input depends on the calculator, but the highest-impact variables are usually rates, time periods, quantities, income, balance, measurements, or unit choices. Change one input at a time to see which variable drives the result.

Why might my Wash Sale Rule Calculator result differ from another website?

Different calculators may use different assumptions, rounding rules, formulas, default values, tax years, unit conversions, or included costs. Compare the formula and assumptions before comparing final answers.

Can I use this investments result for an important decision?

Use the result as a structured estimate and learning tool. For financial, tax, medical, legal, construction, or safety-sensitive decisions, verify the inputs and review the output with a qualified professional.

How often should I update the inputs in the Wash Sale Rule Calculator?

Update the inputs whenever the underlying facts change: rates, prices, measurements, dates, balances, income, rules, or goals. Outdated inputs create outdated answers.

What is the safest way to compare scenarios?

Keep all inputs the same except one variable. That makes it clear whether the difference came from rate, time, quantity, price, measurement, or another assumption.

Calculator

Wash Sale Rule Calculator

Determine if a stock repurchase falls within the wash sale rule window and estimate the disallowed loss.

AnswerCanvas Calculator

Wash Sale Rule Calculator

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Wash sale window status

Within wash sale window

Repurchasing a substantially identical security now would likely disallow the $3,200.00 loss - 12 more days until outside the window.

Days since loss sale: 18
Wash sale window: 30 days (before AND after the sale)
Status: Within window - loss may be disallowed
Days until outside window: 12

Deterministic Formula-backed No stored data

Result chart

Formula

The wash sale rule disallows claiming a tax loss if you buy the SAME or a "substantially identical" security within 30 days BEFORE or AFTER the loss sale (a 61-day window total, counting the sale date itself). This calculator checks the AFTER-sale portion of that window. This is an educational illustration of the rule's timing - determining what counts as "substantially identical" (a real gray area for things like similar-but-not-identical ETFs) requires careful judgment; consult a tax professional for specific situations.

Worked example

Sold at a $3,200 loss 18 days ago: still within the 30-day window, meaning repurchasing the same or substantially identical security now would likely disallow the loss - 12 more days needed to be clear of the window.

Money-page insight

The wash sale window is 61 days total (30 days before + the sale day + 30 days after), not just 30 days - this is a common point of confusion, since simply waiting 30 days after selling ISN'T sufficient if you ALSO bought the same security within the 30 days BEFORE the sale, which is why the full window in both directions needs to be checked, not just the post-sale timing this calculator focuses on.

Calculation history

Stored locally on this device

How the wash sale rule calculator works

How to use this calculator

Adjust the assumptions on the left and the result updates instantly. Use the summary as a planning estimate, then compare it with quotes, local rules, lender disclosures, or professional guidance for decisions involving taxes, loans, construction, or health.

Useful next steps

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Learn more

Stage 1 - Inputs

Collect the required wash sale rule check (educational) values and confirm that each value is physically and logically possible.

Stage 2 - Formula

Stage 3 - Substitute values

Replace each variable in the formula with the current input value. This keeps the calculation transparent and easy to audit.

Stage 4 - Intermediate calculations

Calculate the supporting values first, such as totals, rates, balances, volumes, or ratios, before producing the final result.

Common mistakes

Mixing units, such as monthly and annual rates, inches and feet, or gross and net income
Entering rounded guesses when exact quotes or measurements are available
Ignoring fees, taxes, risk factors, local rules, or physical constraints
Treating an estimate as a final professional decision

Tips

Change one input at a time to understand sensitivity
Use conservative assumptions when the result affects safety, debt, taxes, or health
Save or print the result with assumptions before comparing alternatives
Recheck units whenever a result looks surprisingly large or small

Wash Sale Rule Calculator mastery

Determine if a stock repurchase falls within the wash sale rule window and estimate the disallowed loss.

Use this investments calculator as a working model: enter realistic inputs, read the primary answer first, then use the supporting rows to understand what changed and why.

Read the result correctly

Treat the primary answer as the headline result and the supporting values as the evidence trail behind it.

Improve accuracy

Small input changes can shift the output. Recheck units, time periods, percentages, and any assumptions before using the result.

Use it professionally

Save or print the result with the inputs visible so the calculation can be reviewed, repeated, or compared later.

Expert suggestions

Professional perspective

How to get more value from the wash sale rule calculator

A strong calculation is not only a final number. It is a repeatable way to compare choices, understand assumptions, and see which inputs deserve the most attention.

Best next moveRun the calculator once with realistic inputs, then change only one input at a time so you can see which variable has the biggest effect.

Start with a baseline

Use the most realistic inputs you have today before testing optimistic or conservative cases.

Change one variable

Adjust one assumption at a time. This makes cause and effect easier to understand.

Keep the evidence visible

Save or export the result with inputs included so the answer can be checked later.

Learning path

What to understand next

Understand the main formula
Review the assumptions
Compare alternate scenarios
Decide what information would improve accuracy

Investments insight guide

Understand the answer

Use the wash sale rule calculator as a decision aid, not just a number.

A calculator is most useful when the result, assumptions, and practical meaning are read together. Use the output as a structured estimate and review the inputs before making a decision.

What it tells you

The primary answer summarizes the model. Supporting values explain the path from inputs to output and reveal which assumptions matter most.

What changes the result

The result usually changes when units, rates, time periods, quantities, prices, thresholds, or rounding assumptions change.

What to double-check

Confirm that each input uses the intended unit, time period, percentage basis, and sign. A correct formula can still produce a poor estimate from inconsistent inputs.

When to be careful

Use extra care when the answer affects money, health, safety, legal exposure, construction quantities, or long-term planning.

Accuracy checklist

Confirm every unit before comparing outputs.
Use current inputs rather than outdated estimates.
Test at least one conservative and one optimistic scenario.
Review whether rounding changes the practical decision.

How professionals use this

Document the inputs beside the result.
Compare scenarios instead of relying on a single run.
Share the assumptions when asking for review.
Use expert review for high-stakes decisions.

Trust note: This calculator is designed for transparent estimation. Keep the input assumptions visible when sharing, exporting, or comparing results so another person can reproduce the same answer.

Frequently asked questions

Does the wash sale rule only apply to repurchasing the EXACT same stock?: No - it also applies to "substantially identical" securities, a genuinely gray area that can include things like different share classes of the same company or, in some interpretations, very similar ETFs tracking nearly identical indexes - this requires careful judgment or professional guidance for borderline cases.
What actually happens if I trigger a wash sale?: The disallowed loss doesn't just disappear - it's added to the cost basis of the newly purchased shares, effectively deferring the loss until you eventually sell those new shares (assuming no further wash sale) - it's a timing rule, not a permanent loss of the tax benefit.
Does the wash sale rule apply to gains too, or just losses?: Only losses - there's no such thing as a "wash sale" restriction on claiming gains; the rule specifically exists to prevent investors from claiming tax losses while maintaining essentially the same investment position.
What does the Wash Sale Rule Calculator calculate?: Determine if a stock repurchase falls within the wash sale rule window and estimate the disallowed loss.
How should I read the Wash Sale Rule Calculator result?: Read the primary answer first, then review the supporting values, formula notes, assumptions, and expert suggestions. The supporting values explain why the answer moved and which inputs deserve more attention.
Which input matters most in the Wash Sale Rule Calculator?: The most important input depends on the calculator, but the highest-impact variables are usually rates, time periods, quantities, income, balance, measurements, or unit choices. Change one input at a time to see which variable drives the result.
Why might my Wash Sale Rule Calculator result differ from another website?: Different calculators may use different assumptions, rounding rules, formulas, default values, tax years, unit conversions, or included costs. Compare the formula and assumptions before comparing final answers.
Can I use this investments result for an important decision?: Use the result as a structured estimate and learning tool. For financial, tax, medical, legal, construction, or safety-sensitive decisions, verify the inputs and review the output with a qualified professional.
How often should I update the inputs in the Wash Sale Rule Calculator?: Update the inputs whenever the underlying facts change: rates, prices, measurements, dates, balances, income, rules, or goals. Outdated inputs create outdated answers.
What is the safest way to compare scenarios?: Keep all inputs the same except one variable. That makes it clear whether the difference came from rate, time, quantity, price, measurement, or another assumption.