Tools
Position size and lot size calculator: forex, crypto, futures
Risk and stop first, size second — never the other way around. Enter your balance, risk percent, entry and stop, and get the position size for crypto, forex or futures, plus what you actually lose if the stop hits.
How position size is calculated
One formula covers every market: position size = risk in money ÷ distance from entry to stop. Risk in money is your balance × risk per trade in percent. The stop goes where the chart says, and the size follows from it — not the reverse.
A tight stop allows a bigger position for the same risk; a wide stop forces a smaller one. The loss at the stop stays the same either way. The Trading OS journal uses this exact formula to fill in the size and result of every trade.
Crypto: coins and USDT value
Example: a 10,000 USDT balance at 1% risk is 100 USDT. BTC, entry 60,000, stop 59,000: the stop is 1,000 USDT away per coin, so the position is 100 ÷ 1,000 = 0.1 BTC, worth 6,000 USDT. No leverage is needed at all — the position is smaller than the balance.
Fees eat part of the risk. At 0.05% per side, entering and exiting at the stop costs 0.0005 × (60,000 + 59,000) = 59.5 USDT per coin, so the position becomes 100 ÷ (1,000 + 59.5) ≈ 0.0944 BTC — and the stop plus fees costs exactly 100 USDT.
Forex: lots and pip value
A standard lot is 100,000 units of the base currency. On pairs quoted in dollars (EUR/USD, GBP/USD), a 0.0001 pip on one standard lot is worth $10. Lots = risk ÷ (pips to stop × pip value per lot).
The example from the Trading OS Academy lesson: a $5,000 account at 1% risk is $50. EUR/USD, entry 1.0850, stop 1.0810 — 40 pips. Position 50 ÷ (40 × 10) = 0.125 lots. A broker with a 0.01 lot step opens 0.12 lots — $48 at risk, never more than planned. On GBP/USD with a 90-pip stop the same risk gives 0.056 lots.
On JPY pairs a pip is 0.01, and its dollar value depends on the rate: 100,000 × 0.01 ÷ the USD/JPY rate. At 150 that is about $6.67 per pip on a standard lot — type your own number into the field.
For gold (XAUUSD) and index CFDs, contract size and point value differ from broker to broker — take them from the symbol specification in MT5 or MT4 and enter them into the pip value field.
Futures and indices: whole contracts
For futures, the contract specs set the point value: E-mini S&P 500 (ES) — $50 per point, Micro E-mini S&P 500 (MES) — $5, E-mini Nasdaq-100 (NQ) — $20, Micro E-mini Nasdaq-100 (MNQ) — $2 (CME Group). Contracts = risk ÷ (points to stop × point value).
Example: a $50,000 account at 1% risk is $500. ES with a 10-point stop is $500 per contract, so 1 contract. The same stop in MES is $50 per contract, so 10 contracts. You can't buy a fraction of a contract, so the calculator rounds down — rounding up would quietly raise your risk.
Sources: cmegroup.com
Frequently asked questions
- What risk per trade should I use?
- The calculator won't pick it for you. A common reference is 0.5–1% of the account per trade, fixed before you look at the chart. What matters more than the number is using the same one every time, next to a daily loss limit.
- Does leverage change position size?
- Not the loss at the stop — that comes from size and stop distance. Leverage decides how much margin is locked and where liquidation sits. Check that your stop comes before liquidation in the liquidation calculator.
- Why are lots and contracts rounded down?
- Brokers open size in steps (0.01 lots, 1 contract). Rounding up would add risk beyond your limit; rounding down leaves it slightly below — the calculator shows exactly how much.
- Are spread and slippage included?
- Crypto fees are, as a separate field. Spread and slippage aren't: the real loss at the stop can exceed 1R. The journal shows the actual R of every trade.
Let size and R be calculated for every trade
In the Trading OS journal, risk, position size and the result in R are filled in from entry, stop and exit — with the same formula as here.
No sign-up — the journal runs in your browser; an account is only needed for sync.