Stock profit calculator

Cost is what the position took to open, shares times the buy price plus the buying fee. Proceeds are what closing it returns, shares times the sell price minus the selling fee. The difference, plus any dividends collected along the way, is the profit. Return divides that by the cost, so the same $800 is a 16% return on $5,000 and a 4% return on $20,000.

Annualizing matters when you compare trades of different lengths. A 16% gain in a year is 16% a year. The same gain in three months is about 81% a year, and in four years about 3.8% a year, which is less than a plain index fund did over most four-year stretches. The holding period field makes that comparison honest.

100 shares bought at $50 with a $4.95 commission, sold at $58 with another $4.95. Cost $5,004.95, proceeds $5,795.05, profit $790.10, a 15.8% return. Held 12 months, that is 15.8% annualized; held 3 months, about 79.8%. Break-even was $50.10, the two commissions spread across 100 shares. A 20% target needed a sell at $60.11.

The sell price for a target return is the one row on this page worth writing down in advance. Most losing trades were not bad entries; they were good entries with no exit, held until a gain became a loss. Deciding the target and the stop first, from the stop-loss calculator, turns the exit into a rule. Our piece on position sizing covers the other half: how much to buy so the loss, if it comes, is one you planned for.