Crypto & Stock Wash-Sale 30-Day Window Calendar & Cost Basis Calculator
Track your 61-day wash-sale window (-30 to +30 days) under IRC § 1091, calculating disallowed losses, cost basis adjustments, and Form 8949 Code 'W' entries.
The IRS Wash-Sale Rule (IRC § 1091) disallows a tax deduction on a realized capital loss if you acquire 'substantially identical' stock or securities within a 61-day window (30 days before the sale, the sale date, or 30 days after). The disallowed loss is added to the cost basis of the replacement shares, postponing your tax deduction.
Scenario Parameters
Wash-Sale Basis Adjustment: Original vs. Repurchase vs. Adjusted Basis
How the Crypto & Stock Wash-Sale 30-Day Window & Basis Calculator Works: Plain-English US Tax Guide
When you sell stocks, mutual funds, or ETFs at a loss in a taxable brokerage account, you can use that capital loss to offset other capital gains plus up to $3,000 of ordinary income per year under IRC § 1211.
However, to prevent taxpayers from gaming the system by selling for a tax write-off and immediately buying right back, Congress established the Wash-Sale Rule (IRC § 1091). The 61-Day Statutory Window: A wash sale occurs if you purchase substantially identical stock or securities within: - 30 calendar days BEFORE the sale date, - The day of the sale, OR - 30 calendar days AFTER the sale date.
What Happens When a Wash Sale Occurs? Your loss is NOT destroyed—it is disallowed for the current tax year. The disallowed loss amount is added directly to the cost basis of the new replacement shares you purchased, and the holding period of the old shares is added to the new shares. When you eventually sell those replacement shares without triggering another wash sale, the tax loss is finally realized.
Stock vs. Crypto Distinctions: Currently under federal law, cryptocurrency is classified as property under IRS Notice 2014-21 and has not historically been subject to IRC § 1091 wash-sale rules under the strict letter of the statute, although legislative proposals frequently target this loophole. For equities and options, the rule is strictly enforced by broker 1099-B reporting.
This calculator maps your exact 61-day wash sale window and tracks cost-basis lot adjustments across transactions.
Case Study: Tech Investor Harvesting a $5,000 Loss on Index Funds
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The Mistake: On January 5 (21 days after the sale), Ryan repurchases 100 shares of XYZ at $105.
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Wash-Sale Triggered: Because the repurchase occurred within the 30-day post-sale window, IRC § 1091 disallows the $5,000 tax deduction on his 2025 return.
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Cost Basis Adjustment: The $5,000 disallowed loss is added to his new purchase price ($10,500 + $5,000 = $15,500 new basis, or $155/share).
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The Smart Workaround: If Ryan had instead bought a similar but not 'substantially identical' ETF (e.g. swapping Vanguard S&P 500 VOO for Schwab US Large-Cap SCHX), he could have stayed fully invested in the market while keeping the full $5,000 tax deduction.
Key 2025 / 2026 Statutory Thresholds & IRS Rules
| Statutory Provision / Rule | 2025 / 2026 Benchmark | Impact on US Taxpayers |
|---|---|---|
| 61-Day Statutory Window | -30 to +30 Days | Spans 30 days before sale, day of sale, and 30 days after sale. |
| Basis Adjustment Rule | IRC § 1091(d) | Disallowed loss increases the cost basis of replacement shares. |
| IRA Wash-Sale Trap | Permanent Loss Disallowance | If you trigger a wash sale by buying replacement shares inside an IRA (Rev. Rul. 2008-5), the tax loss is permanently destroyed with zero basis adjustment! |
| $3,000 Annual Loss Limit | IRC § 1211 | Net capital losses beyond capital gains offset up to $3,000 of ordinary income annually, with indefinite carryforward. |
Costly Mistakes & IRS Tax Traps to Avoid
An automatic dividend reinvestment inside 30 days can inadvertently trigger a partial wash sale on recently sold shares.
Rev. Rul. 2008-5 rules that buying shares in an IRA permanently destroys the tax loss; you can never recover the basis inside a tax-sheltered account.
Brokers only track wash sales within their own firm; you are legally responsible for reconciling cross-brokerage wash sales on Form 8949.
Statutory Audit Trail & Policy Context
| Calculation Step / IRC Statutory Line | Amount ($) | Tax Policy Authority & Notes |
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Federal Preemption & Multi-State Application
This calculator operates under federal IRS statutory guidelines (Internal Revenue Code). Federal rules apply uniformly across all 50 states, while local modifications (such as state income tax deductions or exemptions) are reflected in the net take-home and audit trail calculations.