Covered Call Calculator
A covered call combines a long stock position with a short call option sold against that stock. The calculator above lets you adjust the stock entry price, call strike, premium, expiration, implied volatility, and snapshot time to see how the position’s profit and loss changes across different stock prices.
The calculator reports results on a per-share basis, which matches how listed option premiums are quoted. A standard U.S. equity option contract usually controls 100 shares, so multiply the displayed profit or loss by 100 outside the calculator if you want a rough one-contract estimate. The model does not include commissions, bid-ask spreads, taxes, dividends, or early assignment rules.
What the Calculator Does
The covered call calculator estimates the combined profit and loss from two linked positions:
- A long stock position, using the stock entry price as the reference cost basis.
- A short call option, using the strike price, premium, expiration, and implied volatility inputs.
At expiration, the calculator behaves like a standard covered call payoff model. Before expiration, it switches to a mark-to-market estimate, where the short call still has time value and implied volatility can affect the result.
This distinction matters. A covered call has a clean expiration payoff, but before expiration the option may gain or lose value even if the stock has not moved through the strike.
Inputs
- Entry Price is the stock price at the time you enter the covered call. It is also the stock cost basis used in the profit and loss calculation.
- Strike Price is the price at which you may be required to sell the stock if the short call is exercised or assigned.
- Expiration is the number of days until the short call expires.
- Premium is the call premium received per share. If the option quote is $3.00, the calculator uses 3.00.
- Implied Volatility is inferred from the premium by default. You can move the IV input to override that model value for pre-expiration scenarios.
- Risk-Free Rate is used by the option-pricing model before expiration. For simple expiration payoff work, many users leave it at 0%.
- Snapshot Time is the point in time being analyzed. Set it equal to expiration to view the expiration payoff, or move it earlier to estimate a pre-expiration mark-to-market value.
How to Read the Results
The chart shows covered call profit and loss across a range of possible stock prices. Green areas are profitable outcomes, red areas are losing outcomes, and the gray reference line shows what the stock-only position would do from the same entry price.
The vertical strike marker shows where the short call begins to have intrinsic value. The breakeven marker shows the stock price where the premium exactly offsets the stock loss. The summary below the chart highlights the capped upside, breakeven price, and worst modeled loss.
Losses are shown as negative profit and loss values. For example, a maximum loss of $97 per share will appear as -$97.00 in the summary.
Covered Call Formulas
At expiration, ignoring commissions, taxes, dividends, and financing costs, the covered call’s per-share profit and loss is:
Where:
- is the stock entry price.
- is the stock price at expiration.
- is the call strike price.
- is the call premium received per share.
The key expiration values are:
| Metric | Formula | Meaning |
|---|---|---|
| Capped upside | The best per-share outcome once the stock is at or above the strike. When positive, this is the maximum profit shown by the calculator. | |
| Breakeven price | The stock price where the premium offsets the stock loss. | |
| Maximum loss amount | The per-share loss if the stock falls to zero. |
The capped upside formula can be small or even negative if the strike is below your stock entry price and the premium does not offset selling below cost. That is not a calculator error. It means the trade has capped the stock position at an unattractive exit price.
Example
Suppose you own stock at $100 per share. You sell a 30-day call with a $110 strike and collect a $3.00 premium per share.
At expiration:
- Capped upside is $110 - $100 + $3 = $13 per share.
- Breakeven price is $100 - $3 = $97.
- Maximum loss amount is $100 - $3 = $97 per share, assuming the stock falls to zero.
Here are three possible expiration outcomes:
| Stock Price at Expiration | Short Call Outcome | Covered Call Result per Share |
|---|---|---|
| $90 | Expires worthless | -$7 |
| $102 | Expires worthless | $5 |
| $120 | Stock is sold at the $110 strike | $13 |
The last row shows the central tradeoff. The stock rose to $120, but the covered call keeps only $13 per share because gains above the $110 strike are given up in exchange for the $3 premium.
Expiration Payoff vs. Pre-Expiration Value
If the snapshot time is set to expiration, the calculator uses the option’s intrinsic value. In that case, implied volatility no longer changes the final payoff because the option has no time value left.
If the snapshot time is earlier than expiration, the chart estimates what the position may be worth before the option expires. That estimate depends on the remaining time, implied volatility, and interest-rate input. Treat the pre-expiration line as a scenario model, not as a live broker quote.
What the Calculator Does Not Include
- Dividends. Dividends can affect call pricing and early assignment risk, especially near an ex-dividend date.
- Early assignment. U.S. equity options are usually American-style, so assignment can happen before expiration.
- Taxes. Covered call tax treatment can depend on holding period, qualified covered call rules, assignment, and whether the call is closed or rolled.
- Transaction costs. Commissions, bid-ask spreads, and slippage reduce real returns.
- Rolling decisions. Rolling a covered call changes the trade. The calculator models the current stock-plus-short-call position, not a sequence of future rolls.
Frequently Asked Questions
Is this calculator per share or per contract?
It is per share. Option premiums are quoted per share, so a $3.00 premium means $3.00 in the calculator. For a standard 100-share equity option contract, multiply the per-share result by 100 outside the calculator.
Why is covered call profit capped?
The short call gives someone else the right to buy your shares at the strike price. Once the stock rises above that strike, additional stock gains are offset by losses on the short call. You keep the premium, but you give up upside above the strike.
Does the calculator include dividends?
No. Dividends are not included. That matters because dividends can affect option value and early assignment risk. A covered call on a dividend-paying stock may behave differently around the ex-dividend date.
Why does the chart change before expiration?
Before expiration, the short call may still have time value. Its value can change with stock price, time remaining, implied volatility, and interest rates. That is why a pre-expiration snapshot does not always match the simple expiration formulas.
What happens if the stock finishes above the strike?
At expiration, the short call is in the money. In a standard covered call, your broker will usually assign the call and sell your shares at the strike price, subject to broker procedures and exercise thresholds. You keep the original premium and the stock gain up to the strike.