For FX Traders
Free Calculator Suite

The industry standard formula is Lot = (Account Balance × Risk %) / (Stop Loss pips × pip value). This tool applies this formula with 1 pip = 0.01 for JPY-quoted pairs (e.g., USDJPY) and 1 pip = 0.0001 for non-JPY pairs (e.g., EURUSD). 1 standard lot = 100,000 currency units.

Generally 2% or less per trade is recommended. This baseline (advocated by veteran trader Dr. Van Tharp) keeps the ruin probability low during losing streaks: even after 5-10 consecutive losses, more than half of the account remains. This tool warns when risk exceeds 10%.

This means stop loss pips are too large relative to your account balance — even the minimum lot (0.01) exceeds your specified risk %. Three solutions: (1) narrow the stop loss, (2) increase account balance, (3) skip the trade. This tool displays the actual realized risk %, so you can see exactly by how much you exceed.

The pip value differs but the formula itself is the same. USDJPY (JPY-quoted): 1 pip = 0.01, ~1,000 yen per lot. EURUSD (USD-quoted): 1 pip = 0.0001, ~1,500 yen per lot (USDJPY=150 conversion). This tool automatically applies the correct pip value based on the selected pair.

Leverage does not appear in lot sizing itself. Lot is derived from "risk tolerance"; leverage determines "required margin" — they are separate axes. However, large lots with high leverage lower the margin maintenance ratio during drawdowns and increase stop-out risk. Required margin can be checked via the margin calculator.

Pips are the smallest unit of price movement in forex. JPY-quoted pairs (USDJPY/EURJPY etc.): 0.01 yen = 1 pip. Non-JPY pairs (EURUSD/GBPUSD etc.): 0.0001 = 1 pip. Example: if USDJPY moves from 150.00 to 150.10, that is a 10-pip increase.

Because price ranges differ. USDJPY trades in 3-digit values like 130-150, while EURUSD trades in sub-1 decimals like 1.05-1.15. To unify pip units, JPY-quoted pairs use the 2nd decimal (0.01) and non-JPY pairs use the 4th decimal (0.0001) as 1 pip. This tool auto-detects based on the selected pair.

Depends on lot size and pair. For 1 standard lot (100,000 units): USDJPY = 1 pip 1,000 yen / EURUSD = 1 pip ~1,500 yen (USDJPY=150 conversion). For 0.1 lot (10,000 units), 1 pip = 100 yen / ~150 yen. This tool calculates actual P/L based on your input lot size.

Depends on the broker. Some brokers use "sub-pip" notation where 1 pip = 10 points (= 5th / 3rd decimal). Example: USDJPY 150.005 → 0.5 pips = 5 points. This tool only handles pip conversion — for point conversion, please check your broker specifications.

For XAUUSD typically 1 pip = 0.1 (= 0.1 dollar/oz), 1 standard lot = 100 oz. So 1 pip = 10 dollars ≈ 1,500 yen (USDJPY=150). When you select "XAUUSD" in the pair selector, this tool calculates correctly automatically.

The Kelly Criterion is a mathematical formula that derives "the optimal risk % per trade for maximizing capital growth" from win rate and RR ratio. Published by physicist John Kelly in 1956. Formula: f* = W - (1-W)/R (W = win rate, R = avg win/avg loss). Example: with 60% win rate and RR 2.0, f* = 0.60 - 0.40/2.0 = 40% is the "Full Kelly".

Because Full Kelly is only optimal under the theoretical assumption of "infinite trials + perfectly stable win rate / RR". In real trading, win rate estimation errors and drawdowns from losing streaks lead to ruin. Half Kelly (= f*/2) maintains ~75% growth rate while halving drawdown; Quarter Kelly (= f*/4) is even more conservative. This tool displays ruin probability (Cramér-Lundberg method) so you can compare actual risk at each Kelly fraction.

For systems with negative expected value (= win rate × RR < 1 - win rate), the mathematically optimal solution is "do not bet". Example: 40% win rate / RR 1.0 → f* = 0.4 - 0.6/1.0 = -0.2 (negative). This means "this trading system loses money over time" — even Half/Quarter Kelly only delays ruin. The trading system itself needs to be reviewed.

The probability that account balance reaches 50% or less of its initial value. Calculated by the Cramér-Lundberg adjustment coefficient method = expected log growth rate + win/loss distribution to enumerate all ruin paths from losing streaks. Color-coded: ≤5% green (safe), 5-25% orange (caution), >25% red (danger).

For combinations of win rate 30-70% × RR 0.5-4.0, each cell displays the "Full Kelly %". Green (15%+) = safe, orange (5-15%) = standard, red (0-5% / negative) = danger. You can visually grasp where your trading system win rate and RR sit on the zone, and consider improvement direction (= which has bigger effect: improving win rate vs improving RR).