Track shares and value through every split — and the true return between any two dates
| At purchase | Today |
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Stock splits confuse two things that must never be confused: the price per share and the value of your position. A 4-for-1 split quadruples your shares and quarters the price — value unchanged, to the penny. But once history contains splits, raw price comparisons lie: a stock "down" from your $120 purchase to $95 may actually be a +58% winner. This calculator walks your position through any sequence of splits and reverse splits, reporting the true return, your current share count, and the adjusted cost basis the IRS expects at sale.
| Event | Shares | Price | Your value | Basis/share |
|---|---|---|---|---|
| Buy 100 @ $120 | 100 | $120 | $12,000 | $120 |
| 2-for-1 split | 200 | $60 | $12,000 | $60 |
| Price grows to $95 | 200 | $95 | $19,000 | $60 |
Result: the ticker shows $95 vs your $120 "purchase price" — a fake −21% — while the truth is +58%. Every "split-adjusted" chart you've ever seen performs exactly this correction backward through history.
Splits are not taxable events — your total basis is unchanged and simply divides across the new share count (the calculator's adjusted-basis figure). At sale, that adjusted basis determines your gain; brokers track it since 2011, but older or transferred positions still produce basis mysteries at tax time — this math reconstructs them. Gains then flow to the Capital Gains Tax Calculator.
One original Apple share from the 1980 IPO has split into 224 shares (2:1 thrice, 7:1, 4:1); Nvidia's 2021–2024 splits multiplied shares 40×. This is why "the stock was $22 in 1980" statements are meaningless without the split factor — and why this calculator's chained-split selectors exist.
Neither — a split is denominational, like changing a $20 bill into two $10s. Your position value is identical the moment it happens. Any price drift around splits is sentiment, not arithmetic.
No — splits aren't taxable events. Your total cost basis carries over, redistributed per share. You'll care at sale time, which is exactly when the adjusted-basis figure from this calculator matters.
Companies typically cash out fractions (a small taxable sale). After a 1-for-10 on 105 shares, you'd hold 10 shares plus cash for the half-share.
It didn't change your cost — it displays split-adjusted basis so gains compute correctly. Old confirmations show raw prices; the adjusted view is the accounting truth.
Historically split announcements carried small positive drift (companies split after strength), but the effect has weakened since fractional-share investing removed the accessibility rationale. As a strategy: noise. As a signal about management confidence: mildly informative at best.
Everything scales: per-share dividends divide by the split factor (total payout unchanged), and options contracts adjust strike and share count automatically via the OCC. No one gains or loses by the event itself.
Yes — every figure computes locally in your browser.
Whenever a long-held position's return looks wrong, check the split history first — five seconds in this calculator prevents the classic error of judging (or selling) a winner that only looks like a loser in raw prices.