How to Calculate Lot Size in Forex

Position sizing answers one question: how big can this trade be so that, if the stop-loss is hit, I lose the amount I decided on and no more? The answer depends on three numbers: how much you are willing to lose, how far away your stop is, and what each pip of movement is worth. Nothing else goes into it.

• Amount at risk is money in your account currency. With percentage risk it is balance × risk %, so 1% of $10,000 is $100.
• Stop-loss in pips is the distance from your entry price to your stop price divided by the pip size (0.0001 for most pairs, 0.01 for yen pairs).
• Pip value per lot is what a one-pip move is worth on 1.00 standard lot, in your account currency.

The denominator, stop × pip value, is the loss on one full lot if the stop is hit. Dividing the amount you are prepared to lose by that figure gives the number of lots that loses exactly that amount. The rest of this guide is about getting those three inputs right for different instruments and account currencies.

It helps to see the formula as the profit-and-loss formula run backwards. Loss at the stop = lots × stop in pips × pip value per lot. If you fix the loss you will accept, you can solve for lots.

A lot is a standard quantity of the instrument. In forex it is counted in units of the base currency, the first currency in the pair:

Most MT4, MT5 and cTrader brokers let you trade in steps of 0.01 lots, so a "micro lot" is simply 0.01 in the volume box. Some brokers express size in units instead (50,000 rather than 0.50 lots); the maths is identical. The lot converter translates between the two.

Outside forex the word "lot" means whatever the broker's contract specification says it means. These are the defaults calc.forex uses, which match the most common retail specifications:

Index, oil and crypto contracts vary far more between brokers than forex does. One broker's NAS100 lot may be worth $1 per point, another's $10 or $0.10; some oil contracts are 100 barrels rather than 1,000. Before sizing a trade on anything that is not a currency pair, open the symbol's specification in your platform and match the contract size. On calc.forex you can change it under Contract specs in every calculator.

Pip value is the step most people get wrong, because the familiar "$10 per pip" is only true when the pair is quoted in your account currency.

Profit or loss on a currency pair is always earned in the quote currency, the second currency in the pair. The first part of the formula gives the pip value in that currency; the second part converts it into the currency your account is held in.

When the quote currency is your account currency

EUR/USD, GBP/USD, AUD/USD, NZD/USD and XAU/USD are all quoted in US dollars. For a USD account no conversion is needed: 0.0001 × 100,000 = $10 per pip per lot, at any exchange rate. Gold works the same way: $0.10 × 100 oz = $10.

When your account currency is the base currency

USD/JPY is quoted in yen, so one pip is 0.01 × 100,000 = ¥1,000 per lot. To turn yen into dollars, divide by the USD/JPY rate: at 150.00, ¥1,000 ÷ 150 = $6.67. At 140.00 it would be $7.14; at 160.00, $6.25. The pip value of USD/JPY, USD/CHF and USD/CAD in a dollar account changes whenever their price changes.

When neither currency is your account currency

For EUR/GBP in a USD account, a pip is worth £10 per lot, converted at GBP/USD: at 1.2500, £10 × 1.25 = $12.50. For GBP/JPY in a EUR account, ¥1,000 is converted at EUR/JPY: at 165.00, ¥1,000 ÷ 165 = €6.06.

The conversion uses the exchange rate between the quote currency and your account currency, written the way the market quotes it. Multiply when the quote currency is the base of that rate (GBP in GBP/USD); divide when it is the quote (JPY in USD/JPY or EUR/JPY). Trading EUR/USD from a EUR account is the second case: $10 ÷ 1.10 = €9.09 per pip.

These rates are round numbers chosen so you can check the arithmetic by hand. The calculators fill in current reference rates, which you can replace with your broker's quote.

The pip value guide explains pips in more detail and lists the pip value per standard, mini and micro lot for the major pairs, gold and silver.

1. Decide the amount at risk. Either a percentage of your balance (fixed-fractional) or a fixed money amount. Write it down in your account currency.
2. Place the stop where the trade idea is wrong, then measure its distance from the entry in pips. For a long EUR/USD at 1.1000 with a stop at 1.0980, that is 0.0020 ÷ 0.0001 = 20 pips. The stop comes from the chart, the volatility or your strategy rules, not from the size you would like to trade.
3. Find the pip value per lot in your account currency, as above.
4. Divide the amount at risk by (stop in pips × pip value per lot).
5. Round down to your broker's lot step and recheck the actual risk at the rounded size.
6. Check the margin. Make sure the position fits comfortably within your free margin.

Steps 2 and 3 are where the errors happen. A stop measured in the wrong unit (points instead of pips, or the other gold pip convention), or a pip value that skips the currency conversion, produces a lot size that can be wrong by a factor of ten.

All examples use the same round reference rates: EUR/USD 1.10, GBP/USD 1.25, USD/JPY 150 and EUR/JPY 165.

EUR/USD from a USD account

Balance $10,000, risk 1%, stop 20 pips.

Each pip on 0.50 lots is worth $5, so a 20-pip loss is exactly $100.

USD/JPY from a USD account

Risk $100, stop 40 pips, USD/JPY at 150.00.

The "$10 a pip" shortcut would give $100 ÷ (40 × $10) = 0.25 lots here, a third smaller than necessary. The opposite mistake, using $10 for a pair whose pip is worth more (EUR/GBP at $12.50, for example), makes the position too large.

EUR/USD from a EUR account

Balance €10,000, risk 1% (€100), stop 20 pips, EUR/USD at 1.1000.

The euro account can trade a slightly larger size than the dollar account for the same 1%, because each pip is worth fewer euros than dollars.

USD/JPY from a EUR account

Balance €10,000, risk 1% (€100), stop 30 pips. Neither currency in the pair is the euro, so the yen pip value is converted at EUR/JPY (165.00).

Gold (XAU/USD)

Balance $10,000, risk 1% ($100). You buy gold at $4,000.00 with a stop at $3,995.00, a $5.00 move.

calc.forex counts a gold pip as $0.10, so $5.00 is 50 pips, and a pip on one 100-ounce lot is worth $0.10 × 100 = $10.

At the minimum size of 0.01 lots (1 oz), a gold pip is worth $0.10, so the same $5.00 stop risks $5. That is the right size for 1% of a $500 account; with less than $500, or a wider stop, even 0.01 lots risks more than 1%.

Some platforms and traders call $0.01 a gold pip instead. Then the same stop is 500 pips, each worth $0.01 × 100 = $1 per lot, and $100 ÷ (500 × $1) = 0.20 lots: the same answer. The convention does not matter; mixing conventions does. A 500-"pip" stop entered into a calculator that values a gold pip at $10 gives 0.02 lots, ten times too small. A 50-pip stop valued at $1 a pip gives 2.00 lots, ten times too large. The safest habit is to think about gold stops in dollars ($5.00 below entry) and let the calculator convert them.

NAS100 (Nasdaq 100 CFD)

Balance $10,000, risk 1% ($100), stop 80 index points, contract worth $1 per point per lot, lot step 0.1.

If your broker's NAS100 contract is $10 per point, the same trade is 0.125 lots: 0.1 lots (risking $80) with a 0.1 lot step, or 0.12 lots (risking $96) if the broker allows 0.01. Always read the contract size from the platform before trusting an index calculation.

The formula rarely produces a size your broker accepts. Most forex accounts trade in steps of 0.01 lots; many index, commodity and crypto CFDs use 0.1 or 1. Round the exact answer down to the nearest step. Rounding up, or to the nearest step, can push the loss at the stop above your limit.

When the right size is below the minimum lot

Small accounts run into the opposite problem. With $200 and 1% risk, the amount at risk is $2. A 30-pip stop on EUR/USD then needs 0.0067 lots, below the usual 0.01 minimum. The smallest tradable size, 0.01 lots, would lose $3 at the stop: 1.5% of the account. The honest options are to accept the higher percentage knowingly, find a tighter stop that the strategy genuinely supports, use a broker that offers nano lots or unit-based sizing, or skip the trade. Trading 0.01 lots while believing you risk 1% is the one option to avoid.

There are two common ways to set the amount at risk:

• Fixed-fractional (a percentage of the balance): risk a fixed share, such as 1%, of the current balance. Position sizes grow after wins and shrink after losses.
• Fixed-amount: risk the same money on every trade, such as $100, whatever the balance, until you deliberately change it.

Fixed-fractional sizing slows down automatically during a drawdown, which is why it is the most common default. Because each loss is a percentage of a smaller balance, a run of stopped-out trades on its own can never take the account to zero (gaps and slippage aside). The cost is a slower recovery: after a run of losses, the winning trades are smaller too.

Fixed-amount sizing is simpler to reason about and maps neatly onto prop-firm rules, which are usually stated in money. Its weakness is that the percentage at risk rises as the account falls: $100 is 1% of $10,000 but 1.25% of $8,000. Traders who use it typically reset the amount at set intervals or after a set drawdown.

Whichever you use, the lot size formula is the same; only the "amount at risk" input changes. The risk management guide covers how much to risk in the first place.

A fixed 20-pip stop is tight on GBP/JPY on a busy day and wide on EUR/CHF on a quiet one. Many traders set the stop as a multiple of the Average True Range (ATR), a measure of the average range of a bar, and let the formula set the size.

With a daily ATR of 0.0050 on EUR/USD and a 1.5× multiplier, the stop is 0.0050 × 1.5 ÷ 0.0001 = 75 pips. Risking $100: $100 ÷ (75 × $10) = 0.133 lots, rounded down to 0.13 lots, for an actual risk of $97.50. When volatility doubles, the stop doubles and the size halves, so the money at risk stays the same.

Lot size from risk and lot size from leverage answer different questions. The formula above gives the size that loses a set amount at your stop. Leverage decides how much of your balance the broker holds as margin while the position is open.

0.50 lots of EUR/USD at 1.1000 is a position worth 50,000 × 1.10 = $55,000. At 30:1 leverage the broker holds $55,000 ÷ 30 = $1,833.33 as margin; at 500:1, $110. In both cases the loss at a 20-pip stop is $100. Higher leverage does not change the risk of a correctly sized trade. It only frees up margin, which also makes it easier to open trades that are far too large.

Check that the margin for all your open positions leaves a comfortable buffer of free margin, especially if you hold several positions or trade through news. The leverage and margin guide explains margin calls and stop-outs.

• Using $10 per pip for every pair. It is only true for pairs quoted in your account currency. For USD/JPY at 150 it is $6.67; for EUR/GBP with GBP/USD at 1.25 it is $12.50.
• Mixing pip conventions on gold, oil, indices or crypto. A stop measured with one pip size and valued with another is out by a factor of ten or a hundred.
• Assuming every broker's index lot is the same. $1, $10 and $0.10 per point all exist.
• Rounding up. 0.375 lots becomes 0.37, not 0.38.
• Forgetting the spread and commission. You buy at the ask but a long position's stop is triggered by the bid, so the loss at the stop is measured from your fill and includes the spread. Commission is extra. On short stops, costs are a large share of the risk; see the trading costs guide.
• Moving the stop without resizing. Widening a stop from 20 to 40 pips at the same size doubles the risk.
• Treating correlated trades as separate risks. Long EUR/USD and long GBP/USD at 1% each is closer to one 2% bet against the dollar than to two independent 1% trades.
• Forgetting that stops are not guaranteed. Over weekends and around major news the price can gap through a stop, and the fill can be worse than the stop price. The formula sizes the planned loss, not the worst case.

For other balances, scale linearly: a $5,000 account trades half these sizes and a $50,000 account five times as much (then round down again). For pairs not quoted in your account currency, the pip value changes with the exchange rate, so use a calculator rather than this table.