Free Trading Tools — Options Calculator, Position Sizer

Black-Scholes Options Pricing

The Black-Scholes model estimates the theoretical price of European-style options using five key variables. It also computes the Greeks — sensitivities that measure how the option price changes relative to each input.

Stock Price (S)

$

Strike Price (K)

$

Time to Expiration (days)

Risk-Free Rate (%)

Implied Volatility (%)

Call Price

$3.25

Put Price

$2.84

The Greeks

Delta0.5542-0.4458

Gamma0.06920.0692

Theta-0.0451-0.0314

Vega0.11380.1138

Rho0.0429-0.0390

CallPut

How it works

The Black-Scholes formula calculates the fair value of a European option by modeling stock prices as a geometric Brownian motion. Delta measures directional exposure, Gamma measures how fast Delta changes, Theta captures time decay per day, Vega shows sensitivity to volatility shifts, and Rho reflects interest rate impact. All calculations run entirely in your browser.

Position Size Calculator

Determine the optimal number of shares to trade based on your account size and risk tolerance. Proper position sizing is one of the most important aspects of risk management.

Account Balance

$

Risk Per Trade (%)

Entry Price

$

Stop-Loss Price

$

Take-Profit Price (optional)

$

Position Size

100 shares

Dollar Risk

$500.00

Risk Per Share

$5.00

Total Position Value

$15,000.00

60.0% of account

Risk management tip

Most professional traders risk between 1-2% of their account on any single trade. This calculator divides your total dollar risk by the per-share risk (distance between entry and stop-loss) to determine the maximum number of shares you should trade.

Profit / Loss Calculator

Quickly evaluate the outcome of a trade by entering your entry and exit prices. Factor in commissions to see your true net return.

Entry Price

$

Exit Price

$

Number of Shares

Commission Per Trade (optional)

$

Net Profit / Loss

+$1500.00

+10.00%

Gross P/L

+$1500.00

Total Commission

$0.00

Break-Even Price

$150.00

Entry price adjusted for round-trip commissions

Understanding your results

Gross P/L is the raw difference between your exit and entry multiplied by share count. Net P/L subtracts round-trip commissions (entry + exit). The break-even price shows the minimum exit price needed to cover your entry cost plus all commissions.