Forex margin calculator

How do you calculate forex margin?

Required margin = lots x 100,000 x margin percentage, and the answer comes out in the pair's base currency, the first one in its name. The margin percentage is 100 divided by the leverage, so 30:1 means 3.33%. If your account is in another currency, the margin is then converted at one rate.

The default inputs hold one lot of USD/JPY in a US-dollar account at 30:1. The lot is 100,000 dollars, so the margin is 100,000 x 3.33% = $3,333.33. No price or exchange rate is needed, because the margin is already in dollars. With a $10,000 balance, $6,666.67 stays free and the margin level is 10,000 / 3,333.33 = 300%.

Where the leverage calculator measures how geared your whole account is, this page answers the narrower question a platform asks before every order: how much of the balance this one position will lock up, at the rate set for that pair, and how far equity can fall before the close-out level.

Margin percentage and leverage are the same rule

Platforms quote margin either as a ratio or as a percentage. The calculator takes both, and the conversion is a single division:

Halving the leverage doubles the margin. The bar chart in the result draws the same comparison for your own pair, lots and rate, so you can see what a change in the account's setting would free up or tie down.

Why margin is worked out in the base currency

A lot is counted in the base currency, so its margin is too. The help pages of a widely used trading platform, named in the sources below, give the forex margin formula as volume in lots x contract size / leverage, with the result in the symbol's margin currency, which is generally the base currency. The platform then converts it to the deposit currency at the current rate, using the ask price for buys and the bid price for sells, and may multiply it by a margin rate set for the symbol.

This calculator follows the same order. When your account is in the pair's second currency, the pair's price converts the margin: for a dollar account trading EUR/USD at 1.1000, one lot needs 3,333.33 euros of margin at 30:1, which is $3,666.67.

When the account currency is neither side of the pair, the calculator also asks for an exchange rate: how many units of the pair's second currency 1 unit of your account currency buys, the same direction the leverage, pip value and position size calculators use. A dirham account trading EUR/USD therefore types the EUR/USD price and how many US dollars one dirham buys. The calculator holds no live prices and never fills one in.

Free margin, margin level and the room before close-out

Three account figures follow from the required margin:

• Equity = balance + open profit or loss.
• Free margin = equity - all margin in use. It is what is left for new positions.
• Margin level = equity / margin in use x 100. Platforms close positions when it falls to a set level.

The calculator adds a fourth: loss before close-out = equity - close-out level x margin in use. On the default position, with the close-out at 50%, equity can fall from $10,000 to $1,666.67, a loss of $8,333.33, which is an 8.33% move against the $100,000 position. With that much free margin, 2.00 more lots of USD/JPY at the same setting would still fit.

Open trades change all of this. Say the account also has $2,000 of margin used elsewhere and a $1,500 open loss, and you add one lot of EUR/USD at 1.1000. Equity is $8,500 against $5,666.67 in use: free margin $2,833.33, a margin level of 150%, and room for a $5,666.67 loss, a 5.15% move against the new position, before 50%.

Retail margin rules in the US and the UK

Two regulators set floors that read most naturally as margin percentages:

• United States. The Commodity Futures Trading Commission's rule 17 CFR 5.9 sets a minimum security deposit for retail forex of 2% of notional value for major currency pairs and 5% for every other pair. The lower figure counts only when both currencies in the trade are majors, and which currencies count as major is designated by the registered futures association. On one lot of a dollar-based pair such as USD/JPY, the 2% floor is $2,000 when both currencies are designated majors, and the 5% floor is $5,000.
• United Kingdom. The Financial Conduct Authority's page on contracts for difference, last updated 13 June 2025, says firms selling CFDs to retail consumers must limit leverage to between 30:1 and 2:1 depending on the underlying asset, close out a customer's position when their funds fall to 50% of the margin needed to maintain it, and make sure a client cannot lose more than the total funds in their account.

The 50% default under Other positions and the close-out level comes from that UK rule. Firms elsewhere, and professional accounts, may use other levels, so type the one your own platform states.

Margin for mini and micro lots

Margin scales in a straight line with size. At 30:1, a mini lot of USD/JPY (0.1, or 10,000 dollars) needs $333.33 and a micro lot (0.01) needs $33.33. That is why small accounts can open positions at all, and also why a few micro lots on a small balance can use a large share of it.

The figure under More lots the free margin covers divides the free margin by the margin for one lot of the same pair at the same setting and rounds down to 0.01. It is a ceiling on what the platform would accept, not a size anyone has to trade. For sizing from the money at risk instead, the lot size calculator starts from your stop.

Forex margin examples in pounds, dirhams and yen

• Pound account, GBP/USD. £8,000 balance, half a lot at 30:1. The lot is counted in pounds, so the margin is 50,000 x 3.33% = £1,666.67 with no rate needed. Free margin is £6,333.33 and the margin level 480%.
• Dirham account, EUR/USD. AED 40,000 balance, one lot at 30:1 with EUR/USD at 1.1000. The margin is 3,333.33 euros, or $3,666.67. Using 1 AED = 0.2723 USD, an example rate you would replace with the one on your platform, that is AED 13,465.54 and a margin level of 297.05%. With the close-out at 50%, equity could fall by AED 33,267.23, about an 8.24% move against the AED 403,966.21 position.
• Yen account, USD/JPY. ¥1,500,000 balance, one lot at 30:1, price 150. The margin is $3,333.33, or ¥500,000, and the margin level is again 300%.

Pick a currency and the calculator chooses a pair counted in it where one exists, so the default needs no price or rate. Changing the currency never rescales a rate or a price you typed.

How to calculate forex margin in Excel or Google Sheets

With lots in B2, leverage in C2, the pair's price in D2 and the rate 1 account currency = x second currency in E2, the required margin is =B2*100000/C2*D2/E2. Put 1 in E2 when the account is in the pair's second currency, and 1 in both D2 and E2 when it is in the first. For a margin percentage in C2 instead, written as 0.02 for 2%, use =B2*100000*C2*D2/E2.

Add the balance in F2 and the margin in G2, then free margin is =F2-G2 and margin level is =F2/G2 (formatted as a percentage). The loss before a 50% close-out is =F2-0.5*G2. For several positions, sum their margins first and use the total as G2.

What this calculator leaves out, and common mistakes

It works one position at a time against the balance you enter and does not follow prices. It ignores the spread, swap and commission, margin rates a platform applies on top of leverage, hedged-position margin rules, and the margin call warnings some firms send before closing anything. The room before close-out counts only the new position's move; open trades that lose at the same time use it up faster.

• Converting from the quote currency. Margin starts in the base currency, so a dollar account trading USD/JPY needs no rate at all.
• Reading free margin as spare cash. It shrinks with every open loss.
• Using the account's top leverage for every pair. Under the US rule, any pair that is not two majors needs at least 5%, not 2%.
• Treating margin as the most you can lose. The loss depends on the position size and the price move, not on the deposit.

Glossary

Required margin: the deposit a position ties up while it is open. Margin percentage: required margin as a share of the position value; 100 divided by the leverage. Base currency: the first currency in a pair, in which a lot is counted. Equity: balance plus open profit or loss. Free margin: equity minus margin in use. Margin level: equity divided by margin in use, as a percentage. Close-out level: the margin level at which the platform closes positions. Notional value: the full value of the position.

Frequently asked questions

Courses behind forex margin

Sources and review