A Forex EA That Dominates The Market
Home / size Calculator
Manage your risk per trade professionally
A Forex Position Size Calculator determines the exact number of lots to trade based on three inputs: your account balance, your risk percentage per trade, and your stop loss distance in pips. It is the core tool of risk management in forex — ensuring that no single trade can cause disproportionate damage to a trading account.
To use this calculator effectively, you need to understand its four components:
The calculator uses this formula:
Lot Size = (Account Balance × Risk %) ÷ (Stop Loss in Pips × Pip Value)
Practical example: You have a $1,000 account and risk 1% ($10). Your stop loss is 50 pips. The calculation: $10 ÷ (50 × $10) = 0.02 lots.
Had you entered 0.10 lots instead, a 50-pip stop loss would cost you $50 — 5% of your account on a single trade. Five consecutive losses at that size wipes 25% of your capital. That is not a bad strategy. That is a sizing problem.
Choose the exact pair you are trading from the dropdown. The calculator automatically adjusts pip value for each instrument — selecting the wrong pair produces an incorrect lot size.
Enter your current account equity in USD — not your deposited balance. If you have open positions with floating losses, your equity is lower than your balance. Equity is the accurate measure of what you have available to risk right now.
Example: deposited $2,000, but have an open trade with $150 floating loss → your equity is $1,850. Enter 1850.
Enter the percentage of your account you are willing to lose if this trade hits stop loss.
Enter the distance from your entry price to your stop loss, measured in pips.
The hint text under the field shows the pip measurement rule for your selected pair. The most important one for gold traders:
💡 Gold (XAUUSD) Stop Loss Conversion:
After clicking Calculate, three lot size values appear:
| Value | What It Means | Where to Use It |
|---|---|---|
| Standard Lot | The primary result. Lot size floored to 2 decimal places — conservative, never rounds up. | Enter directly into MT4/MT5 Volume field when trading standard accounts |
| Mini Lots | Standard lot × 10. Some platforms or brokers display volume in mini lots. | Use if your platform shows volume in mini lots (0.1 = 1 mini lot) |
| Micro Lots | Standard lot × 100. Useful for cent accounts or micro-lot brokers. | Use for cent accounts or platforms that display micro lot volume |
The result also shows Pip Value at your lot size — this tells you exactly how much each pip movement is worth in dollars at the lot size you will trade. Use this to sanity-check your stop loss cost: multiply pip value by your stop loss distance to confirm it equals your intended risk amount.
Alex’s rule: Do not round up the lot size result. If the calculator returns 0.03 lots, enter 0.03 — not 0.05 because it feels rounder. Rounding up means risking more than your calculated percentage, which compounds over many trades into a meaningfully different risk profile.
In MetaTrader, open your order window (F9 on MT4, or click New Order). Find the Volume field and enter the Standard Lot result from the calculator exactly as shown. Then set your stop loss price to match the pip distance you entered in Step 4.
For EAs: enter the lot size in the EA’s Inputs tab under the lot size or volume parameter before attaching to the chart. Do not use the EA’s default lot size unless you have verified it matches your intended risk calculation. For step-by-step EA configuration, see how to install a forex robot on MT4 — Step 4 covers the Inputs tab setup.
| Pair | EUR/USD |
| Account Balance | $1,000 |
| Risk % | 1% |
| Risk Amount | $10 |
| Stop Loss | 50 pips |
| Pip Value per Lot | $10.00 |
| Lot Size | $10 ÷ (50 × $10) = 0.02 lots |
| Mini Lots | 0.20 |
| Micro Lots | 2.00 |
| Pair | XAUUSD (Gold) |
| Account Balance | $3,000 |
| Risk % | 0.5% (EA setting) |
| Risk Amount | $15 |
| Stop Loss | 150 pips (= $15.00 price move) |
| Pip Value per Lot (XAUUSD) | $1.00 |
| Lot Size | $15 ÷ (150 × $1) = 0.10 lots |
| Mini Lots | 1.00 |
| Micro Lots | 10.00 |
Note how gold allows a larger lot size (0.10) than EURUSD at the same dollar risk — because gold’s pip value is $1/lot instead of $10/lot. This is a common point of confusion for traders switching between pairs.
| Pair | USD/JPY |
| Account Balance | $5,000 |
| Risk % | 1% |
| Risk Amount | $50 |
| Stop Loss | 40 pips |
| Current USD/JPY Rate | 150.00 (example) |
| Pip Value per Lot | (0.01 × 100,000) ÷ 150 = $6.67 |
| Lot Size | $50 ÷ (40 × $6.67) = 0.18 lots |
JPY pip value fluctuates with the exchange rate — this is why the calculator requires you to enter the current live rate for JPY pairs. At USD/JPY 120.00, the same inputs would give a different lot size. Always use the rate at the moment you are about to enter the trade, not a rate from earlier in the day.
This table shows calculated lot sizes across common account sizes, risk percentages, and stop loss distances.
Pip value assumed at $10 per standard lot for major USD pairs (EUR/USD, GBP/USD, AUD/USD). Important for gold traders: XAUUSD pip value is $1.00 per standard lot — not $10. If you are sizing a gold position, the table results still apply only if you enter your stop loss distance converted correctly (10 pips on gold = $1.00 price move). For a dedicated XAUUSD position size reference, see the pip value calculator.
| Account Balance | Risk % | Risk $ | SL: 20 pips | SL: 50 pips | SL: 100 pips |
|---|---|---|---|---|---|
| $500 | 1% | $5 | 0.02 | 0.01 | 0.00 |
| $1,000 | 1% | $10 | 0.05 | 0.02 | 0.01 |
| $1,000 | 2% | $20 | 0.10 | 0.04 | 0.02 |
| $5,000 | 1% | $50 | 0.25 | 0.10 | 0.05 |
| $5,000 | 2% | $100 | 0.50 | 0.20 | 0.10 |
| $10,000 | 1% | $100 | 0.50 | 0.20 | 0.10 |
| $10,000 | 2% | $200 | 1.00 | 0.40 | 0.20 |
| $50,000 | 1% | $500 | 2.50 | 1.00 | 0.50 |
Gold traders need a separate reference because XAUUSD calculates differently from forex pairs. On XAUUSD: 1 pip = $0.01 price movement, contract = 100 troy oz, pip value = $1.00 per standard lot (not $10). This means the formula produces different lot sizes for the same dollar risk.
Example: $1,000 account, 1% risk ($10), stop loss 100 pips on gold. Lot size = $10 ÷ (100 × $1) = 0.10 lots. On EURUSD with the same inputs: $10 ÷ (100 × $10) = 0.01 lots. Gold allows 10× larger lot size at the same dollar risk because pip value is 10× lower.
| Account | Risk % | Risk $ | SL: 50 pips gold ($5 move) | SL: 100 pips gold ($10 move) | SL: 200 pips gold ($20 move) | SL: 300 pips gold ($30 move) |
|---|---|---|---|---|---|---|
| $500 | 1% | $5 | 0.10 | 0.05 | 0.02 | 0.01 |
| $1,000 | 1% | $10 | 0.20 | 0.10 | 0.05 | 0.03 |
| $1,000 | 2% | $20 | 0.40 | 0.20 | 0.10 | 0.06 |
| $3,000 | 1% | $30 | 0.60 | 0.30 | 0.15 | 0.10 |
| $5,000 | 1% | $50 | 1.00 | 0.50 | 0.25 | 0.16 |
| $10,000 | 1% | $100 | 2.00 | 1.00 | 0.50 | 0.33 |
| $10,000 | 2% | $200 | 4.00 | 2.00 | 1.00 | 0.66 |
Stop loss distances for gold are measured as price moves: 50 pips = $5.00 price move, 100 pips = $10.00 price move. For context on how gold EAs manage stop loss placement on XAUUSD, see the best gold forex robot comparison.
Note: Values are floored to 2 decimal places (minimum tradeable lot on most brokers is 0.01). A result of 0.00 means the account is too small to safely trade that stop loss distance at that risk level — reduce stop loss or increase balance before trading.
When running an automated EA — particularly grid-based or martingale systems — position sizing requires a different approach than manual trading. An EA can open multiple positions simultaneously, meaning total account exposure compounds with every new order.
At 1% risk per trade with 5 concurrent open positions, you are already at 5% total account exposure. If the EA uses a martingale multiplier, that figure can double or triple within the same drawdown cycle. For grid EAs like the Oreshnik gold robot, keeping individual trade risk at 0.5% or lower gives the system enough margin to manage drawdown without triggering a margin call mid-sequence.
Before setting EA lot parameters, use this calculator to determine the correct base lot for your account size and intended risk level. If the EA requires a fixed lot input rather than a risk percentage, calculate the lot first — then enter that number into the EA’s input settings. For a step-by-step walkthrough of EA input configuration, see how to install a forex robot on MT4 — Step 4 covers the Inputs tab where lot size is set.
If you want to see how verified live-account EAs manage drawdown in practice, the best MT4 forex robots comparison includes real Myfxbook equity data — not just balance curves — across 10+ systems.
This web-based calculator works alongside MT4 and MT5 — you calculate your lot size here, then enter the result directly into your platform’s order window. Here is the exact workflow:
The Volume field in MT4 and MT5 accepts lot sizes to 2 decimal places (e.g. 0.03, 0.15, 1.20). Most brokers set minimum volume at 0.01 lots. If the calculator returns 0.00, your account balance is too small to safely trade that stop loss distance at the stated risk percentage — either tighten your stop loss or increase account balance.
If you want position sizing calculated automatically inside MT5 without switching to a browser, a position size EA (Expert Advisor) can do this. A position size EA reads your account balance and stop loss level directly from the chart and outputs the correct lot size in real time.
To install and configure any EA in MT5, including position size utilities, see the complete guide: how to install a forex robot on MT5. Note that a position size EA is a utility EA — it calculates lot sizes but does not place trades automatically. For the difference between trading EAs and utility EAs, see what is a forex EA.
MT4 uses the same Volume field and the same lot size inputs. The calculation from this tool applies identically to MT4 and MT5 — pip values and contract sizes are the same across both platforms for all major pairs and XAUUSD. For MT4-specific EA installation, see how to install a forex robot on MT4.
At 1% risk ($10) with a 50-pip stop loss, the correct lot size is 0.02 lots. At 2% risk ($20) with the same stop loss, it is 0.04 lots. Always calculate based on your specific stop loss distance — not a fixed lot number. Two traders with identical account balances but different stop loss distances should trade completely different lot sizes.
Gold uses the same formula, but pips are measured differently. On XAUUSD, 10 pips equals a $1.00 price move. Example: buy at 2000.00, stop loss at 1995.00 = $5.00 distance = 50 pips. Enter 50 in the Stop Loss field — the calculator handles the rest. The pip value assumption of $10 per standard lot applies correctly to XAUUSD on standard accounts.
Position size is the total notional value of a trade. Lot size is the standardised unit MT4 and MT5 use to express that value. A standard lot equals 100,000 units of base currency — or 100 troy ounces for gold. A mini lot is 0.10, a micro lot is 0.01. Most retail traders operate between 0.01 and 1.00 lots depending on account size.
Yes. Pip value differs across pairs — particularly for JPY pairs and commodities like XAUUSD. This calculator uses $10 per pip per standard lot, which is accurate for major USD-quoted pairs and gold. For exotic pairs or accounts denominated in non-USD currencies, pip value will vary. Use the pip value calculator to confirm exact pip value before trading non-major pairs.
For automated EAs — especially grid or martingale-style systems — keep risk per trade at 0.5% or lower. EAs can open multiple positions simultaneously, so total portfolio exposure compounds quickly. At 1% risk per trade with 5 open positions, you are already at 5% total account exposure. For EAs running on gold with current high volatility, 0.5% or less is not conservative — it is necessary.
Calculate your lot size using the web calculator above — enter account balance, risk %, and stop loss distance in pips — then manually enter the result in MT5’s New Order window in the Volume field. Alternatively, install a position size EA (utility type) inside MT5 that reads your stop loss directly from the chart. To install any EA in MT5, including position size utilities, see how to install a forex robot on MT5.
Use the XAUUSD-specific table above. Gold’s pip value is $1.00 per standard lot — not $10. At $1,000 account, 1% risk ($10), and a 100-pip stop loss: lot size = $10 ÷ (100 pips × $1) = 0.10 lots. On EURUSD with identical inputs, the result would be 0.01 lots. Gold allows larger lot sizes at the same dollar risk because its pip value per lot is 10× lower than major forex pairs.
On most brokers, the minimum tradeable lot size is 0.01 lots (micro lot). If the position size calculator returns 0.00 for your inputs, it means the account is too small to risk only 1% on that stop loss distance — you would need to widen the stop loss, reduce risk%, or increase account balance. Never round a 0.00 result up to 0.01 to force a trade — that is not risk management, it is ignoring the math.
Four steps: (1) Determine account equity in USD. (2) Decide risk % per trade — typically 1% for manual trading, 0.5% or less for EAs. (3) Identify stop loss distance from entry to stop price in pips. (4) Apply the formula: Lot Size = (Account Balance × Risk%) ÷ (Stop Loss Pips × Pip Value per Lot). For major USD pairs, pip value = $10 per standard lot. For XAUUSD, pip value = $1 per standard lot. The calculator on this page does this automatically.
Silver (XAGUSD) uses a different contract size than gold — typically 5,000 troy ounces per standard lot, with 1 pip = $0.001 price move. Pip value at standard lot = $5.00 (5,000 oz × $0.001). At 0.01 lot, pip value = $0.05. Use the pip value calculator to confirm pip value for XAGUSD at your intended lot size, then apply the same formula: Lot Size = Risk $ ÷ (SL pips × pip value).
Lot Size = (Account Balance × Risk %) ÷ (Stop Loss in Pips × Pip Value)