How do you calculate lot size?
Lot size comes from one division: lots = money at risk / loss per lot if the stop is hit. The loss per lot is the stop distance multiplied by what one lot gains or loses for each step in price. For a forex pair that step is a pip; for gold, silver, an index or Bitcoin it is a 1.00 move in the price, scaled by the contract size.
The default inputs show it. A $5,000 account risking 2% has $100 on the line. One standard lot of EUR/USD moves $10 a pip, so a 40-pip stop costs $400 a lot, and $100 / $400 = 0.25 lots. That is 25,000 euros of the pair, the same as 2.5 mini lots or 25 micro lots, and the table under the result lays those out side by side.
The answer is then rounded down to the 0.01-lot step most platforms accept, so a rounded size never loses more at the stop than you set. The exact figure stays in the working.
Standard, mini and micro lots: how many units is a lot?
A lot is a fixed bundle of the thing you trade. In forex a standard lot is 100,000 units of the base currency, the first currency in the pair; a mini lot is a tenth of that and a micro lot a hundredth. Gold, silver and index CFDs use the same 1.00, 0.10 and 0.01 steps, but the bundle behind one lot is whatever the platform's contract size says.
| Lot type | Lots | EUR/USD units | EUR/USD per pip | Gold at 100 oz: ounces | Gold per 1.00 move |
|---|---|---|---|---|---|
| Standard | 1.00 | 100,000 | $10.00 | 100 | $100.00 |
| Mini | 0.10 | 10,000 | $1.00 | 10 | $10.00 |
| Micro | 0.01 | 1,000 | $0.10 | 1 | $1.00 |
The Units and lots converter tab does this both ways for any contract size. Type 35,000 units with a 100,000 contract and it returns 0.35 standard lots, 3.5 mini lots or 35 micro lots. Type 25 ounces of gold against a 100-ounce contract and it returns 0.25 lots.
Lot size calculator for gold (XAUUSD)
Gold is priced in US dollars per troy ounce, so a 1.00 move in the price is worth the number of ounces in one lot. With the common 100-ounce contract, a 6.00 stop costs $600 a lot. Risking $100, the size is 100 / 600 = 0.1667 lots, which rounds down to 0.16 lots, or 16 ounces, and the loss at the stop is $96.
Contract size is where gold sizing goes wrong. If your platform's specification showed 10 ounces a lot instead, the same $100 and the same 6.00 stop would allow 1.66 lots, more than ten times as many, for exactly the same money at risk. That is why this calculator asks for the contract size instead of assuming one.
Silver works the same way with a bigger bundle. At 5,000 ounces a lot, a 0.25 stop in the silver price is a $1,250 loss per lot, so $100 at risk is 0.08 lots.
Lot size for NAS100, US30 and other index CFDs
Index CFDs have no single standard lot. One platform may pay 1 dollar per point per lot on NAS100, another 10 or 20. The calculator multiplies your stop in points by the contract size you type, in the currency the index is priced in, and divides your risk by the result.
- NAS100, contract size 1, 40-point stop. One lot loses $40 at the stop, so $100 at risk is 2.50 lots. With a contract size of 10, it is 0.25 lots.
- US30, contract size 1, 60-point stop. One lot loses $60, so $100 at risk gives 1.6667 lots, rounded down to 1.66.
For an index priced in euros, pounds, yen or Australian dollars, pick that currency under Index priced in. If it differs from your account currency, the page asks for the exchange rate before it gives a size.
Lot size for BTCUSD and other crypto CFDs
A Bitcoin CFD is often 1 bitcoin a lot, so a 1.00 move in the price is worth $1 a lot. Stops on Bitcoin are wide in price terms: a 1,500 stop costs $1,500 a lot, so $100 at risk is 0.0667 lots, which rounds down to 0.06 lots. If your platform sets the contract at 0.1 bitcoin, the same inputs allow ten times the lots.
This is sizing for a CFD quoted in lots. For coins bought outright on a crypto exchange, sizing is by coin count, and the position size calculator handles that. For leveraged crypto positions, the crypto liquidation price calculator shows where the position would be closed out.
Where to find the contract size in MT5 and MT4
In MT5 and MT4, right-click the symbol in Market Watch and choose Specification. The window lists the contract size, the number of units in one lot, along with the minimal volume and the volume step, as your broker sets them. This calculator rounds down to 0.01 lots; if your volume step is larger, round down to that step instead.
On any other platform, look for the contract specification of the instrument. Some platforms take order sizes in units rather than lots, so convert between them with the converter tab before you type a size.
Contract sizes, minimum sizes and the leverage on offer differ by platform and by where you live, since regulators in many places limit retail leverage. Those limits cap the largest position you can open; they do not change the size this page works out from your risk. The leverage calculator shows what a position does to your equity once it is open.
Worked examples in pounds and dirhams
When the instrument is priced in a currency your account does not use, the page asks for one rate, written as 1 unit of your account currency = how many units of the quote currency, and divides the loss per lot by it.
- Pound account, gold. A £4,000 account risking 1.5% has £60 at risk. With 100 ounces a lot and a 6.00 stop, one lot loses $600; at 1 GBP = 1.27 USD that is £472.44. The size is 60 / 472.44 = 0.1270 lots, rounded down to 0.12 lots.
- Dirham account, EUR/USD. An AED 20,000 account risking 1% has AED 200 at risk. At 1 AED = 0.2723 USD, a pip on one lot is worth AED 36.72, so a 30-pip stop costs AED 1,101.73 a lot. The size is 0.1815 lots, rounded down to 0.18 lots.
A pound account trading EUR/GBP, or a yen account trading USD/JPY, needs no rate: the pair opens quoted in your own currency and the rate field stays hidden.
Lot size and pips: how the stop and the risk move the answer
Lot size moves in the opposite direction to the stop. With $100 at risk on EUR/USD, a 20-pip stop allows 0.50 lots, 40 pips 0.25 lots, 60 pips 0.16 lots and 80 pips 0.12 lots. Double the stop and the lots halve, before rounding. The bar chart in the result draws this for whatever you enter.
The money at risk works the other way: double it and the lots double. Contract size divides straight into the answer, so a contract ten times larger means a tenth of the lots. Leverage appears nowhere in the formula. A higher leverage setting lets you open a bigger position, but the lot size that keeps the stop-out loss at your chosen figure stays the same.
Common lot size mistakes, and what this calculator leaves out
- Assuming every gold or index lot is the same. Contract sizes differ between platforms; copy yours from the specification.
- Reading 0.1 lots as one micro lot. 0.1 lots is one mini lot, or ten micro lots.
- Using 0.0001 as the pip on yen pairs. On USD/JPY, EUR/JPY and GBP/JPY a pip is 0.01, so a lot is worth 1,000 yen a pip.
- Typing the stop in pips for gold. For metals, indices and Bitcoin this page wants the stop as a distance in price, such as 6.00 on gold.
The size is worked out before spread, commission, swap and slippage, and a stop can fill beyond its price in a fast market or after a weekend gap. The page does not check your margin or your platform's minimum volume. The pip value calculator gives the value of a move for a size you already hold, and the forex margin calculator shows the margin a size ties up.
Glossary
Lot: the unit of trade size on a forex or CFD platform. Standard, mini and micro lot: 1.00, 0.10 and 0.01 lots. Contract size: the units behind one lot, such as 100,000 currency units or 100 ounces, shown in the platform's specification. Base currency: the first currency in a pair, the one a forex lot is counted in. Quote currency: the second currency, in which the price and the pip value are stated. Volume step: the smallest change in lots a platform accepts. Stop distance: the gap between entry and stop, in pips for forex and in price for everything else.
Frequently asked questions
How do I calculate lot size in forex?
Divide the money you are prepared to lose by the stop in pips times the pip value of one lot. With $100 at risk, a 40-pip stop and $10 a pip on EUR/USD, that is 100 / 400 = 0.25 lots.
How do I calculate lot size for gold (XAUUSD)?
Work out what one lot loses at the stop, which is the stop in price times the ounces in a lot, and divide your risk by that. At 100 ounces a lot, a 6.00 stop loses $600 a lot, so $100 of risk is 0.16 lots after rounding down. Check the contract size in your platform first.
What lot size should I use for NAS100 or US30?
It depends on the contract size your platform uses and your stop in points. At a contract size of 1, a 40-point stop on NAS100 with $100 at risk is 2.50 lots, and a 60-point stop on US30 is 1.66 lots. The page does the arithmetic; the risk you choose is yours.
What is the lot size for BTCUSD?
With a contract of 1 bitcoin a lot, each 1.00 move is worth $1 a lot. A 1,500 stop with $100 at risk gives 0.06 lots after rounding down. Some platforms use a smaller contract, which changes the answer.
How many units are in a standard, mini and micro lot?
In forex a standard lot is 100,000 units of the base currency, a mini lot 10,000 and a micro lot 1,000. For gold, silver and indices, multiply 1.00, 0.10 or 0.01 lots by the contract size in your platform.
Where do I find the contract size in MT5?
Right-click the symbol in Market Watch and choose Specification. The window lists the contract size, the minimum volume and the volume step. MT4 shows the same window.
Is 0.01 a micro lot?
Yes. 0.01 lots is one micro lot, 0.10 lots is one mini lot and 1.00 lot is one standard lot. On EUR/USD a micro lot is worth ten cents a pip to a dollar account.
Does leverage change my lot size?
Not the lot size that matches your risk. Leverage decides how big a position the margin in your account can open, while the lot size here comes only from your risk, your stop and the contract size.
How do I convert units to lots?
Divide the units by the contract size. 35,000 units of a forex pair is 0.35 lots, and 25 ounces of gold at 100 ounces a lot is 0.25 lots. The converter tab also shows the mini and micro lot equivalents.
Why is my lot size rounded down?
Platforms take sizes in steps, usually 0.01 lots. Rounding up would lose more than your chosen risk at the stop, so the page rounds down and shows the exact figure in the working.
Courses behind lot sizing
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See what the course coversSources and review
Last reviewed 13 November 2026 by the NIFM Academy editorial team. Next review by 13 May 2027.
- Lot sizing arithmetic, lots = money at risk / (stop distance x value of one step per lot), rounded down to 0.01; the working is printed under every result. Checked 13 November 2026.
- Contract conventions, forex standard lot of 100,000 base-currency units with a pip of 0.0001, or 0.01 on yen-quoted pairs; gold, silver, index and Bitcoin contract sizes vary by platform and are entered by the visitor. Checked 13 November 2026.
- MetaQuotes, MetaTrader 5 Help and MetaTrader 4 Help, Market Watch pages, the Specification command in the Market Watch context menu lists the contract size (units in one lot), the minimal volume and the volume step, as set by the broker. Checked 13 November 2026.