Stock Calculator

Estimate your stock trading profit, return on investment, and break-even share price using your buy and sell prices, share count, and commissions. This page also keeps the formula, examples, FAQs, and references close by so you can check the result with confidence.

What This Stock Calculator Helps You Do

Profit equals net selling value minus net buying value. Review the formula and examples below if you want to see how the result is derived.

This page is meant to give you a fast answer, but it also helps you double-check the math before you make a decision. Start with the inputs that you already know, run the calculation, and then compare the output with the formula, examples, and FAQs below so you can see whether the answer fits the situation you are modeling.

If the result looks off, the usual causes are a unit mismatch, a missing decimal, the wrong scenario, or a value that needs to be entered as a rate instead of a total. The notes on this page are designed to make those checks easy without forcing you to leave the calculator and search for context elsewhere.

  • Use the calculator first for a quick estimate.
  • Use the formula to understand how the result is built.
  • Use the examples to compare common use cases.
  • Use the references when the answer depends on a standard or assumption.

Common Checks

A quick result is useful, but the best result is one that still makes sense when you look at it a second time. If you are comparing scenarios, try changing one input at a time so you can see which variable has the biggest impact on the final answer. That makes it much easier to spot whether the calculation matches your expectations.

It also helps to keep the context of the problem in mind. A calculator can tell you the math, but you still need to decide whether the input represents a total, a rate, an average, or a category-specific assumption. When in doubt, start with a simple example from the page and scale up from there.

  • Check that every unit matches the rest of the problem.
  • Keep rates, totals, and averages separate.
  • Adjust one variable at a time when testing scenarios.
  • Use the smallest realistic input first, then scale upward.

Scenario Planning

This calculator is especially useful when you want a quick answer before you commit time, money, or effort. Try one baseline input set, then change a single number and compare the result so you can see how sensitive the answer is to that variable.

That makes the page useful for more than just arithmetic. It becomes a small decision aid that helps you compare options, test assumptions, and explain the final number with confidence when you need to share it with someone else.

shares
$
$
%
%

Result

--

Quick Answer: Profit equals net selling value minus net buying value. Review the formula and examples below if you want to see how the result is derived.

How to Calculate Stock Calculator

  1. Enter your trade size: Set the number of shares you bought or sold.
  2. Add your prices and commissions: Provide the buy price, sell price, and percentage commissions.
  3. Read profit and ROI: Compare the result to your initial cost to see how the trade performed.

Stock Calculator Formula

Profit = [(SP × No) - SC] - [(BP × No) + BC]
Variable Meaning Unit
SP Selling stock price $
BP Buying stock price $
No Number of shares shares
BC/SC Buying and selling commissions %

Worked Examples

USA - Simple winning trade
  • Shares: 100
  • Buying price: $85
  • Selling price: $100

Result: $1,390 profit

The stock price increased enough to cover both commissions and generate profit.

USA - Break-even estimate
  • Shares: 100
  • Buying price: $85
  • Selling price: $85

Result: $85.85 break-even

You need a slightly higher selling price to cover the commissions.

How to Interpret Your Results

Range Meaning Action
Negative profit The trade lost money Check whether commissions or a lower exit price caused the loss.
Near zero profit You are close to break-even A small price move changes the outcome materially.
Positive profit The trade made money Compare the return on investment against your target.

Frequently Asked Questions

Yes. It includes percentage commissions on both the buy and sell side.

ROI is the profit divided by the total amount you invested, expressed as a percentage.

It is the selling price that makes your net trade result equal to zero.
Planning note: This is a simplified trading estimate. Taxes, slippage, and market impact are not included.

References

Last reviewed: April 2026