Position Size Calculator for Stocks, Forex & Crypto

Account size (USD)

Risk per trade

Trade

Entry price

Stop loss

Take profit (optional)

Fractional shares

Position size

Dollar risk

Position value

Stop distance

Reward at target

Risk : reward

Breakeven win rate

before fees

Quick Answer

Position size is the dollar amount you are willing to lose divided by how far price can move against you before your stop is hit. Size from the stop, not from how much you want to own, and every trade risks the same slice of the account no matter how volatile the instrument is.

Dollar risk = account size x risk %. Example: $25,000 x 1% = $250.

Stocks and crypto: units = dollar risk / (entry - stop). $250 / $2 = 125 shares.

Forex: lots = dollar risk / (stop in pips x pip value per lot). $100 / (30 x $10) = 0.33 lots.

Breakeven win rate = 1 / (1 + R). A 2R target needs to win 33.3% of the time.

Why size from the stop

Most blown accounts do not come from one terrible pick. They come from a normal losing streak hitting positions that were too big. If every trade risks 1%, ten losses in a row take roughly 10% off the account. Annoying, not fatal. At 5% per trade, the same streak costs about 40%, and you need a 67% gain just to get back to even.

Sizing from the stop also makes trades comparable. A tight stop on a slow stock and a wide stop on a volatile coin can risk exactly the same $250. The share count changes, the risk does not. Our guide to trading risk management goes deeper on picking a risk percentage and handling drawdowns.

Forex lot size and pip value

Forex adds one step: the stop is measured in pips, and the dollar value of a pip depends on the pair. A pip is 0.0001 for most pairs and 0.01 for pairs quoted in Japanese yen. One standard lot is 100,000 units of the base currency, a mini lot is 10,000 and a micro lot is 1,000. The calculator rounds down to the nearest micro lot (0.01) so you never risk more than you asked for.

Pair type	Example	Pip value per standard lot
USD quoted	EUR/USD, GBP/USD	Always $10
USD based	USD/CAD at 1.3700	10 / 1.37 = about $7.30
USD based, JPY	USD/JPY at 150.00	1,000 / 150 = about $6.67
JPY cross	EUR/JPY, with USD/JPY at 150.00	1,000 / 150 = about $6.67
Other cross	EUR/GBP, with GBP/USD at 1.2700	10 x 1.27 = $12.70

For a cross pair, the calculator asks for one extra rate so it can convert the quote currency into dollars. For yen, Swiss franc and Canadian dollar crosses it asks for the USD/xxx rate; for euro, pound, Aussie and kiwi crosses it asks for the xxx/USD rate, which is how those pairs are normally quoted. If you trade forex mostly, our roundup of forex trading platforms compares charting and data across them.

Risk to reward and the win rate you need

R:R on its own does not tell you whether a setup is good. It tells you how often the setup has to work. The breakeven win rate is 1 / (1 + R), so the trade-off looks like this:

Risk : reward	Breakeven win rate	What it feels like
1 : 1	50.0%	Fees push you below even unless you win more than half
1 : 1.5	40.0%	A common middle ground for swing setups
1 : 2	33.3%	You can be wrong twice for every win
1 : 3	25.0%	Long losing streaks are normal, so size small

If you do not know your win rate yet, backtest the setup before trusting either number. How to backtest a trading strategy covers the basics, and the day trading strategies for beginners and swing trading strategies guides show where traders usually put stops and targets.

Planning the trade on a chart

The numbers here are only as good as the stop and target you feed in. In the ChartingLens chart app, the Long Position and Short Position drawing tools let you drag entry, stop and target onto the chart and read the risk to reward and P&L right there, so the levels come from actual support, resistance and volatility instead of round numbers.

Frequently Asked Questions

Decide how many dollars you are willing to lose on the trade, usually 1% or 2% of the account. Divide that by the distance between your entry and your stop. For a $25,000 account risking 1% ($250) with an entry at $50 and a stop at $48, the risk per share is $2, so the position is 125 shares.

Work out the stop distance in pips and the pip value of one standard lot (100,000 units) in your account currency. Lots = dollar risk divided by (stop pips x pip value per lot). Risking $100 with a 30 pip stop on EUR/USD, where one pip on a standard lot is $10, gives 0.33 lots.

JPY pairs use a pip of 0.01. One standard lot moves 1,000 yen per pip, which is about 1,000 divided by the USD/JPY rate in dollars. At 150.00 that is about $6.67 per pip per standard lot, so the pip value changes as the rate moves.

There is no single good number, because it depends on your win rate. A 1:2 trade only needs to win about 33% of the time to break even, and a 1:3 trade needs 25%. A 1:1 trade needs over 50% once costs are included. Pick the ratio your strategy can actually hit.

Breakeven win rate = 1 / (1 + R), where R is reward divided by risk. At 2R that is 1 / 3, or 33.3%. The calculator ignores commissions, spreads and slippage, so your real breakeven is a little higher.

Many traders cap risk at 1% to 2% of the account per trade. At 1%, ten losers in a row cost about 10% of the account, which is survivable. At 5%, the same streak costs about 40%. The calculator warns you when risk goes above 5%.

No. It sizes the trade from the price distance between entry and stop. If your broker charges commissions or a wide spread, set the stop a little tighter in the math or lower the risk so the real loss stays inside your budget.