How to Calculate Position Size: Stocks, Forex and Crypto Examples

Two traders can take the exact same setup — same entry, same stop, same target — and end up with completely different results. The difference is almost always position size.

Position sizing is the least exciting part of trading and the one that decides whether you survive long enough to get good. This guide gives you a single formula and shows it working across stocks, forex and crypto.

The one formula you need

Every position sizing method boils down to three inputs:

1. Account size — the capital in the account you're trading
2. Risk per trade — the percentage of that account you're willing to lose if the stop is hit
3. Stop distance — how far your stop is from your entry

From those:

Position size = (Account × Risk %) ÷ Stop distance per unit

That's it. Notice what's not in the formula: how confident you feel, how good the chart looks, or how much leverage is available.

Step 1: decide your risk per trade

Many retail traders use somewhere between 0.5% and 2% per trade. The exact number is personal, but the logic is simple: with 1% risk, ten losses in a row — which happens to everyone eventually — costs you roughly 10% of the account, not half of it.

For the examples below we'll use a $10,000 account and 1% risk, so the maximum loss per trade is $100.

Step 2: place your stop first

Your stop belongs where the trade idea is proven wrong — below a higher low, beyond a support or resistance zone, outside a range. It does not belong wherever produces a nice round position size.

Pick the stop from the chart. Then let the math tell you how big the position can be.

Example 1: stocks

• Entry: $50.00
• Stop: $48.00 (below a recent swing low)
• Stop distance: $2.00 per share

Position size = $100 ÷ $2.00 = 50 shares (a $2,500 position).

If the stop were tighter at $49.00, you could take 100 shares. If it were wider at $46.00, only 25. The dollar risk stays at $100 each time.

Example 2: forex

In forex, stop distance is measured in pips, and each pip has a value that depends on the lot size. For EURUSD in a USD-denominated account:

Say your stop is 25 pips away:

• Risk per standard lot = 25 pips × $10 = $250
• Position size = $100 ÷ $250 = 0.4 lots (four mini lots)

Pip values differ for pairs where USD isn't the quote currency, like USDJPY or EURGBP, so check your platform's pip value before sizing. If you're new to pips, start with how to read a forex chart.

Example 3: crypto

• Entry on BTC: $60,000
• Stop: $58,800
• Stop distance: $1,200 per BTC

Position size = $100 ÷ $1,200 ≈ 0.083 BTC (about $5,000 notional).

Crypto's volatility usually means wider stops, which means smaller positions. That's not a flaw — it's the formula doing its job. More on volatility in reading crypto charts with AI.

Leverage doesn't change your risk

This is the most common misunderstanding in crypto and forex. In the BTC example, you could open that 0.083 BTC position with $5,000 of your own money, or with $500 at 10× leverage. Either way, if the stop at $58,800 is hit, you lose about $100.

Leverage changes how much margin is tied up. It does not change the loss at your stop. What leverage does change is how close your liquidation price sits to your entry — so always make sure your stop triggers well before liquidation would.

Don't forget costs

Real losses are usually a bit bigger than the formula says because of:

• Spread and commissions on entry and exit
• Slippage when the market moves fast, especially around news
• Funding or swap fees if you hold overnight or hold perpetual futures (see crypto funding rates explained)

A practical habit: size for slightly less than your full risk budget to leave room for these.

A quick checklist before every trade

1. Where is the idea invalidated? That's the stop.
2. What's the stop distance in dollars, pips or points?
3. What's 1% (or your number) of the account today?
4. Divide. Round down, never up.
5. Check that the target offers a reward worth the risk — see risk management for retail traders.

Where ChartPilot helps

ChartPilot's AI chart analysis gives you a structured read of key levels and invalidation zones, which makes step one — deciding where the stop belongs — faster and more consistent. The sizing itself stays with you. Log the planned size next to the result in your trading journal and you'll quickly see whether you're sticking to your own rules.

This article is for educational purposes only and is not financial advice. Trading involves risk, including the loss of capital.