What this covered call calculator measures
A covered call pairs owned shares with a short call on the same underlying. The premium partly offsets a stock decline; the call limits gains on the shares that cover it. The Options Industry Council covered call explanation describes that trade-off. The stock can still lose most of its value.
This manual tool assumes standard contracts covering 100 shares each. It includes every share entered, including shares without a call. It rejects uncovered calls and fractional contracts. It does not fetch quotes, model adjusted deliverables, or change your tax basis. Enter a separate budget for omitted fees and taxes when assessing an actual trade.
Reconcile the stock and call legs
Let S be expiry stock price, C purchase price, N all shares, K strike, P premium per share, and Q = 100 × contracts. Q must not exceed N. Before fees, taxes, and dividends:
Stock P/L = (S − C) × N
Short call P/L = [P − max(S − K, 0)] × Q
Combined P/L = stock P/L + short call P/L
Net investment = C × N − P × Q
With N = Q, expiry profit is capped at (K − C) × N + P × Q. With N greater than Q, residual stock keeps uncapped upside. Maximum modeled loss occurs at zero stock price. The breakeven below the strike is (C × N − P × Q) / N if that value is between zero and K. A fully covered position whose cap is negative never breaks even; residual shares may instead produce a zero crossing above K.
Read each result on its own assumptions
Flat-price and at-strike returns
Flat-price return uses the entered current price as the expiry price. At-strike return assumes expiry at K, including residual shares marked at K. Both divide P/L plus the optional dividend estimate by the original cost of all shares.
Expiry payoff chart
The chart starts at zero and includes exact strike and breakeven points. It shows all-share P/L before dividends and costs, using straight segments. It is a scenario diagram, not a historical backtest.
Premium offset per share
Total premium divided by all shares shows the average initial offset to a stock decline. This is not insurance against loss, and it is smaller per share when only part of the stock position covers calls.
Optional dividend approximation
Estimated dividends equal current price × annual dividend yield × all shares × days / 365. This smooth accrual is only a scenario assumption; actual dividends depend on declared amounts, dates, ownership, and possible early assignment.
A reproducible comparison
Use current price $150, purchase price $148, 100 shares, one $155 call, $3.50 premium, 30 days, and no dividends. The stock costs $14,800 and premium is $350. Expiry P/L is −$14,450 at zero, $0 at $144.50, $550 at $150, and $1,050 at or above $155. Flat-price return is 550 / 14,800 = 3.72%; at-strike return is 1,050 / 14,800 = 7.09%.
Change shares to 150 while keeping one call. Premium remains $350, but all-share cost becomes $22,200. At $180 the result is (180 − 148) × 150 − (180 − 155) × 100 + 350 = $2,650. Each further $1 rise adds $50 from the residual shares. A $1,050 maximum would be incorrect for this partially covered position.
- Enter current price and original cost separately. For a new buy-write they can be the same; for existing stock they often differ.
- Check the contract multiplier and whether all calls are covered. This page supports only standard 100-share delivery.
- Keep dividend yield at zero unless you intend to compare the stated approximation. Verify real ex-dividend dates separately.
- Compare zero-price, flat-price, strike, and rally scenarios. Deduct expected trading costs outside this calculator.
Annualization does not make the return repeatable
Annualized return is period return × 365 / days, with no compounding. At zero days it is unavailable. A short period can produce a large displayed annualized number without a repeatable trade: premiums, volatility, stock prices, and assignment outcomes change. The calculator provides no probability estimate or recommended expiry.
Strike and assignment trade-offs
OTM call
K is above the current stock price. Covered shares can appreciate up to K, but collecting a premium does not prevent a stock loss.
ATM call
K equals the current stock price in this tool. There is no universal balanced-risk classification; costs, volatility, and holding objectives still matter.
ITM call
K is below the current stock price. Part of the premium reflects intrinsic value, so a larger premium alone does not establish a better return.
Check exercise and cash flows before trading
An American-style call can be assigned before expiry, including around an ex-dividend date. Assignment may remove the covered shares before a dividend is earned. The OIC assignment FAQ explains why assignment cannot be predicted from the displayed payoff alone. At the strike, confirm exercise status with the broker.
Rolling closes one option and opens another; it can realize a loss, add costs, and extend stock exposure. Neither a fixed 30–45 day expiry nor a Delta range is established here as optimal. Delta is a model sensitivity, not a verified chance that your particular call will expire worthless.