Covered Call Calculator: 6 Formulas, a Worked Example and 40 Backtests

A covered call calculator turns a stock price, a strike, a premium and days to expiration into six numbers: your premium yield, the annualized yield, the return if your shares are called away, your breakeven, the price where the cap starts to cost you, and a rough chance of assignment. Premium ÷ stock price gives the yield, × 365 ÷ DTE annualizes it, and stock price − premium is the breakeven. Our free covered call calculator runs the premium, yield, breakeven and buffer on a live quote where one is available. The rest is below, with a worked example and what 40 simulated backtests say about the number most calculators leave out.

Run the numbers now: open the Days to Expiry covered call calculator, enter a ticker, your capital, days to expiration and fees per contract.

The six formulas

A covered call means you own 100 shares and sell one call against them. You keep the premium either way. If the stock finishes above the strike at expiration, your shares are sold at the strike.

Capital            = Stock price × 100 × Contracts
Premium collected  = Premium per share × 100 × Contracts − Fees
Premium yield      = Premium collected ÷ Capital        (= Premium ÷ Stock price before fees)
Annualized yield   = Premium yield × 365 ÷ DTE
If-called return   = (Strike − Stock price + Premium) ÷ Stock price
Breakeven          = Stock price − Premium per share
Upside cap         = Strike + Premium per share
Assignment odds    ≈ Call delta

Which price to divide by. Most calculators, ours included, divide by today's stock price, because that is what the shares are worth and what you'd get if you sold them instead. If you bought the shares lower and track your true cost basis after rolls, the yield on cost is higher. Both are valid; just don't compare one trade on price with another on cost.

Annualized is simple, not compounded. Multiplying by 365 ÷ DTE assumes you can repeat the same trade at the same premium all year. Use it to compare a 14-day call with a 45-day call, not as a forecast.

Delta is an approximation. A 0.30 delta call has roughly a 30% chance of finishing in the money at expiration, based on the option's implied volatility. It says nothing about early assignment, which is most likely just before an ex-dividend date.

A worked example (hypothetical)

Say you own 100 shares of a stock trading at $100. You sell one 35-day $102 call for $1.50 a share. Its delta is 0.35 and your broker charges $1 per contract.

Three outcomes at expiration:

• Stock at $97. The call expires worthless. You keep $149, and the shares are down $300, so the position is down $151. The premium softened the drop; it didn't prevent it.
• Stock at $101. The call expires worthless. You keep $149 plus a $100 gain on the shares: $249.
• Stock at $110. The shares are called away at $102. You make $349, the if-called maximum. Holding the shares without the call would have made $1,000.

That last line is the trade-off. The 1.5% downside buffer is small, and the cap at $103.50 is close. A covered call works best on a stock you expect to drift sideways or rise slowly.

How our calculator works

On the calculator page, choose Covered Call (the default) and enter your capital, ticker, days to expiration, implied volatility and fees per contract. It then:

• Loads the current stock price and targets a call strike 2% above it.
• Looks up a live premium for the listed strike nearest that target, within a week either side of your DTE, and shows the strike it actually quoted. If no quote comes back, it falls back to an estimate from the IV field.
• Works out how many contracts your capital covers (capital ÷ (stock price × 100), rounded down). If it covers none, it tells you how much you'd need.
• Shows monthly income (net premium × 30 ÷ DTE), annual yield on the capital, breakeven and the downside buffer.

The risk-level buttons set the delta range used when you open the setup in the Strategy Analyzer, where you can see assignment odds for each live strike. To scan many tickers at once instead of one, use the covered call screener or compare the tools in covered call screener and calculator tools.

What the yield leaves out: the cap, in 40 backtests

A premium-yield calculator only shows what you collect. It doesn't show what you give up when the stock runs through your strike. To see how much that matters over time, we looked at our simulated wheel backtests: 40 tickers, 20 September 2024 to 18 September 2026, selling 35 DTE puts and calls 2% out of the money and holding each to expiration.

These are backtests on modelled option prices for every ticker below, not live trades. They cover the full wheel (puts, then covered calls after assignment), so they're not a pure covered-call test, and they don't transfer to other strikes or DTEs.

Across all 40 tickers, the wheel finished behind buy-and-hold on 23. The median call-away rate was 50%. The pattern in the table is the cap at work: on strong runs like SMH, QQQ and SPY, getting called away 2% above the price left most of the move on the table. On flat or falling names like COST, the premium was the return.

The same data also tested closing each position at 21 DTE instead of holding to expiration. That version trailed hold-to-expiry on all 40 tickers, with a median gap of 20.7 percentage points of total return.

The takeaway for using a calculator: a 15% annualized yield on a covered call is not 15% more than holding the stock. If the stock rallies, the yield is all you get.

What the calculator can't tell you

Whether the premium is worth the cap. Compare the if-called return with what you think the stock could do before expiration. If a 3.5% maximum looks small next to the move you expect, sell a higher strike or skip the call.

Dividends and early assignment. A call that is in the money before an ex-dividend date can be assigned early, and you lose the dividend. Check the dividend calendar before picking an expiration.

Earnings. An earnings report before expiration can gap the stock above your strike or well below your breakeven.

The alternative trades. A cash-secured put at the same strike has a similar payoff to a covered call; see cash-secured put vs covered call and the cash secured put calculator guide. If you don't want to tie up capital in 100 shares, a synthetic covered call with LEAPS needs less.

A short routine

1. Pick a stock you're happy to hold, and a strike you'd be happy to sell it at.
2. Run it through the calculator for premium, annualized yield after fees and breakeven.
3. Work out the if-called return and the upside cap (strike + premium) by hand.
4. Check the call's delta as your rough assignment odds, and check the dividend and earnings dates.
5. Once the trade is on, track realized yield across all your calls with covered call portfolio tracking, not just the premium on each one.

FAQ

How do you calculate the return on a covered call?

Divide the premium by the stock price to get the premium yield for the trade. A $1.50 premium on a $100 stock is 1.5%. To compare trades of different lengths, annualize it by multiplying by 365 divided by days to expiration. At 35 days that is about 15.6% before fees.

What is the if-called return on a covered call?

It is the premium plus the gain from the stock rising to the strike, divided by the stock price. Selling a $102 call for $1.50 on a $100 stock returns ($2.00 + $1.50) / $100 = 3.5% if the shares are called away. It is the most the trade can make.

What is the breakeven on a covered call?

The stock price you paid minus the premium you collected. Buy at $100, sell a call for $1.50, and you break even at $98.50. The premium only cushions a small drop; below the breakeven you lose almost dollar for dollar with the stock.

When does a covered call do worse than just holding the stock?

Whenever the stock finishes above the strike plus the premium. In the example above that is $103.50. In a simulated two-year wheel backtest on 40 tickers (35 DTE, 2% out of the money), the strategy finished behind buy-and-hold on 23 of them.

Does the Days to Expiry covered call calculator show the if-called return?

No. It shows premium income, monthly income, annual yield on the stock's value, breakeven and the downside buffer, using a live premium for a strike about 2% out of the money where one is available. Work out the if-called return by hand with the formula in this article.