Wash Sale Rule Calculator
The formula
What the wash sale rule tells you
The share one quantity represents of another — the core reading behind wash sale rule — with a second value folded in for direct comparison.
Calculation: percentage = part ÷ whole × 100. Enter your inputs and every substitution is shown below the result.
Reading the result
Percentages without denominators mislead: always pair the share with the absolute figures above before acting.
Limitations and best practice
Bases must match (same period, same definition of “whole”); comparing a share computed on one base against another is the most common error in dashboards.
This calculator gives an estimate based on standard formulas; it is not professional financial, medical, legal or engineering advice. Verify anything you plan to act on with a qualified professional and your own records.
Frequently asked questions
When is a percentage misleading?
Can it exceed 100 %?
Source & methodology
Elementary percentage arithmetic.
Wash Sale Rule: what this tool answers
This page was written for one job: turning your own inputs into a defensible figure, with the working shown. Searchers land on a Wash Sale Rule page for three reasons — to plan, to compare options, and to check that somebody else’s arithmetic is honest. This tool serves all three, and everything after the calculator explains the model instead of hiding it.
The useful way to hold Wash Sale Rule is as a ratio with a story attached: percentage = part ÷ whole × 100 says how the parts combine, and the 14.21% figure above is simply that sentence written in numbers. Everything that follows unpacks one clause of the sentence at a time.
A calculation like this one is worth roughly as much as a careful sentence: it forces several vague considerations into one comparable quantity. Once Wash Sale Rule is on the table, the argument can stop being about impressions.
Nothing below is stock text pasted around a number: the worked example computes share = 14.21% from this tool’s own defaults, and the sensitivity section ranks the inputs that move the result — Whole / total first, at ≈11.1 % of the headline for a ten-percent error either way in that input. Work down the page and by the end you could re-derive the result in a spreadsheet from memory.
Every input in Wash Sale Rule, and what it does to the answer
One formula, published in full: percentage = part ÷ whole × 100. Anything you can read, you can reproduce in a spreadsheet, and that reproducibility is the whole point of printing it rather than hiding it behind a button.
Part / amount (example value 270) is a plain measured quantity — the unit shown in the label is the unit the formula expects. Keep every money input in the same currency; mixing systems quietly corrupts the comparison.
Whole / total (example value 1,900) is a quantity rather than a category — precision here is cheap and worth having. If you are unsure what belongs in this field, look at the printed steps: the substitution shows exactly how the engine uses it.
Compare with second value (example value 190) is a quantity rather than a category — precision here is cheap and worth having. The example value is there to demonstrate the mechanics, not to describe your situation — overwrite it.
Wash Sale Rule on the example inputs: the complete substitution
The tool prints its own working; this is the same arithmetic on the example values, reproduced so you can follow it by hand. Starting figures: Part / amount, Whole / total, Compare with second value. The endpoint of that chain is 14.21% of share, sitting in the “Minor but material share” band.
- Divide 270.00 by 1,900.00 = 0.1421
- Multiply by 100 → 14.21 %
Second value as % of whole — 10.00%. If your inputs change, this is usually the first companion figure to move.
Ratio part : whole — 0.142. If your inputs change, this is usually the first companion figure to move.
Per 100 units — 14.21. Compare it against the main result of 14.21% before drawing conclusions.
Overwrite any input above and every line of this example updates with it — the substitution is live, not a screenshot of somebody else’s numbers.
The Wash Sale Rule corridor: your result across a realistic band
The honest version of any estimate is a corridor, and this one is cheap to produce: Wash Sale Rule was recomputed at 5 points along the dominant input, with every other field left untouched.
| Whole / total setting | Share |
|---|---|
| 80 % of the example value | 17.76% |
| 90 % of the example value | 15.79% |
| example inputs | 14.21% |
| 110 % of the example value | 12.92% |
| 120 % of the example value | 11.84% |
That spread — 11.84% at the low end, 17.76% at the high — is what a careful read of Wash Sale Rule looks like: a band you can state out loud, with the reason for each edge. Reproduce it in the form above by editing Whole / total alone; the substitution steps will follow your figures exactly.
What actually moves your Wash Sale Rule
Nobody should have to guess which input matters. The engine was re-run once per field below — ten percent up, ten percent down, everything else frozen — and the results ranked by how far they moved the share. For Wash Sale Rule the ranking is measured rather than guessed, and it belongs to these defaults: shift the starting point and the order can shift with it.
- Nudge Whole / total by ±10 % and Wash Sale Rule lands between 12.92% and 15.79% (sensitivity ≈11.1 %)
- Nudge Part / amount by ±10 % and Wash Sale Rule lands between 12.79% and 15.63% (sensitivity ≈10.0 %)
Whole / total is the dominant lever here: ten percent either way moves the result by about 11.1 %, from 12.92% to 15.79%. Measure that input from a document rather than from memory, and treat Part / amount as the second priority (≈10.0 % per ten percent). Everything below that can stay approximate, which is a licence to stop chasing data that would not change the decision.
Is your Wash Sale Rule good — reading the result bands
Nobody acts on a bare figure — they act on a figure with a comparison attached. The default case lands in the “Minor but material share” band, and bands are deliberately wide because real situations overlap. How much of that band is luck? On Whole / total alone ten percent either way covers 12.92% to 15.79%. The practical reading rules: read the band as a starting hypothesis, then test it: change the two dominant inputs by ten percent and see whether the verdict survives. Verdicts that survive stress are the ones worth acting on.
Related measures answer related questions, and the distinctions matter: Wash Sale Rule is the quantity, Share is this tool’s reading of it, and the decision that follows belongs to neither of them separately.
Common mistakes with Wash Sale Rule (and the fix)
Bases must match (same period, same definition of “whole”); comparing a share computed on one base against another is the most common error in dashboards. This calculator gives an estimate based on standard formulas; it is not professional financial, medical, legal or engineering advice. Verify anything you plan to act on with a qualified professional and your own records.
Confusing annual with monthly rates. A "1 % per month" fee is roughly 12.7 % annualized; the calculator takes one convention, and picking the wrong one can misstate Wash Sale Rule by double digits.
Attention is also misallocated between fields. Having measured this engine, we can say where it belongs: Whole / total first, everything else second.
A final trap is presentation: reporting Wash Sale Rule to more decimal places than the inputs support. The tool prints what the arithmetic gives; you should quote only what your least precise field justifies.
A quick check for any Wash Sale Rule figure
- Record the date and the inputs alongside the number so future-you knows what was assumed.
- Re-run the calculation with a ±10 % stress on the two most sensitive inputs.
- Check Whole / total before anything else: it is the measured dominant input, ≈11.1 % of Wash Sale Rule per ten percent.
- Compare the output against one published benchmark or a colleague’s independent estimate.
- Compare the result with one independent method or published benchmark.
- Repeat the ±10 % test on the inputs that matter and see whether the decision — not just the number — still holds.
How to use the Wash Sale Rule tool properly
Using a calculator well sounds trivial, but the difference between a decision-grade figure and a throwaway one lives entirely in the routine. The routine for Wash Sale Rule takes a minute to learn and applies to every input above.
Step 1 — gather before you type. Wash Sale Rule depends on part / amount, whole / total, compare with second value. Collect them from a source document — a statement, a report, an invoice, a log — rather than from memory, because recalled inputs are the single largest cause of wrong results. If the verdict changes with a ten-percent nudge, report the nudge alongside the number.
Step 2 — start from the case you can defend. Enter pessimistic-but-honest figures first; the optimistic run is a ceiling, not a plan. A conclusion that holds on conservative inputs holds everywhere. Estimates improve most when the worst case is written down in ink.
Step 3 — change one input at a time. Nudge a single field by ten percent, watch the headline and its companions move, then undo it. Two or three fields will dominate — the sensitivity table above already ranks them for this engine. Suspiciously tidy answers deserve the same scrutiny as untidy ones.
Step 4 — ask what would have to be true. Take the result you want and work backwards through the inputs until you find the assumption that produces it; then decide honestly whether that assumption is defensible. Write the assumptions in the same file as the result, and future arguments take minutes instead of meetings.
Step 5 — save the story with the figure. A number without its inputs and its date is unusable within a quarter. Record 14.21%, the assumptions behind it, and today’s date; your future self will be auditing a stranger’s arithmetic. The inputs are the part of the work that nobody else can do for you.
The real-world conversations Wash Sale Rule settles
Numbers earn their keep in conversations, and Wash Sale Rule is no exception. In Finance & Banking discussions around Taxes, this figure decides whether an option stays on the table: it converts an opinionated debate into an arithmetic one, and arithmetic is the only referee both sides accept. The point of transparency is that a reader can disagree with a specific line rather than with you.
Professionals in Taxes use this style of calculation as a screening filter before spending real money or effort: a quick Wash Sale Rule check eliminates weak options in minutes, and the survivors earn the deeper, slower analysis. One decimal place more than your data supports is one decimal place of fiction.
There is a personal-administration use people overlook: periodic self-checking. Wash Sale Rule quietly drifts as life changes — rates move, bodies change, costs compound — and re-running it a few times a year catches drift while correction is still cheap. When in doubt, prefer the boring input: the interesting one is usually the one you misread.
People also ask about Wash Sale Rule
What affects Wash Sale Rule the most?
Measured on this engine, Whole / total is the dominant lever: moving it ±10 % shifts the share across 12.92% to 15.79% — about 11.1 % of the headline, with Part / amount next at ≈10.0 %. The ranked list in the sensitivity section is computed live, not asserted from a template.
Which matters more: part / amount or whole / total?
Whole / total, by a factor of about 1.1. Concretely: ten percent on Whole / total is worth ≈11.1 % of Wash Sale Rule, the same nudge on Part / amount only ≈10.0 %. That ranking is re-computed for each page from that page’s own defaults.
What is a typical Wash Sale Rule?
With the example inputs on this page the result is 14.21%, labelled “Minor but material share”. “Typical” varies with situation, which is why every result here ships with its verdict band and its sensitivity list: they turn one figure into a range you can locate yourself inside.
How do I calculate Wash Sale Rule by hand?
percentage = part ÷ whole × 100 is the entire method. Work the inputs in that order — Divide 270.00 by 1,900.00 = 0.1421 — and you will reach 14.21% on the default figures, the same number this tool prints.
What happens to Wash Sale Rule if whole / total changes by 10 %?
On these inputs a ±10 % change in whole / total takes Wash Sale Rule to 12.92% against the 14.21% example — around 11.1 % of the headline. The same test on every other field is in the sensitivity section.
Is the Wash Sale Rule result of 14.21% good or bad?
Good and bad are comparisons, so the honest test is three questions: where does your own Wash Sale Rule sit against the 14.21% reference above, how far would a plausible input error move it (≈11.1 % per ten percent on Whole / total), and what does the alternative option compute to?
How often should I check Wash Sale Rule?
Whenever an input changes by more than a few percent, and otherwise on the rhythm of your decisions — before a purchase, a review, a renewal. Wash Sale Rule is a snapshot, not a subscription; stale snapshots are the most common silent error in Finance & Banking planning.
Does inflation change Wash Sale Rule?
Any money figure that stretches over months is an inflation-sensitive number. A Wash Sale Rule of 14.21% today is a different real value next year; divide by the inflation factor when comparing across time.
When is a percentage misleading?
When the whole is small — 50 % of two is still two. Check absolute numbers alongside every share.
Can it exceed 100 %?
Yes — part can exceed whole for growth and coverage metrics; the ratio output makes that visible.
Does this Wash Sale Rule tool store my numbers?
No. The entire calculation runs in your browser session; nothing entered above is transmitted or saved, which is the correct behaviour for sensitive Finance & Banking figures and the reason you can re-run this page as often as you like.
What the labels on this page mean
- Second value as % of whole
- 10.00% for the Wash Sale Rule worked case; it sits next to the main result because it carries context the headline leaves out.
- Ratio part : whole
- 0.142 on the example inputs — a companion figure printed beside the headline of Wash Sale Rule so that no result is read in isolation.
- Per 100 units
- 14.21 in the default Wash Sale Rule calculation — one of the secondary figures an experienced reader checks before trusting the primary number.
- Share
- The primary output of this tool: 14.21% for the default inputs, computed exactly from percentage = part ÷ whole × 100.
- Worked example
- Every substitution in order, from the example inputs to 14.21% — the audit trail for the headline figure.
- Verdict band
- A named zone on the range of plausible results; the example inputs land in “Minor but material share”, and your inputs may not.
- Sensitivity (±10 %)
- How far the Wash Sale Rule moves when a single input is nudged ten percent either way; the ranked list on this page is computed live from this engine.
Method, sources and what this tool cannot tell you
The model is published arithmetic implemented exactly as written: percentage = part ÷ whole × 100. Source of record: Elementary percentage arithmetic. Where a professional version of this calculation differs, it differs in inputs and jurisdiction-specific coefficients, not in the algebra — which is why re-checking your inputs beats hunting for a second calculator.
This page is an estimation aid, not professional advice. The design rule is simple: two people entering identical figures must get identical answers. Nothing is smoothed, weighted or adjusted behind the scenes; where judgement enters, this page says so and names the input responsible.
Next steps after the calculation
Save the number together with its inputs and today’s date; a Wash Sale Rule figure without context is unusable the moment an input changes.
This page was written for people who need one trustworthy number before their next decision, and the promise is that nothing above required trust. Bookmark the tool, re-run it whenever an input moves by more than a few percent, and keep the date with the number.