Forex Margin Calculator: Required Margin by Leverage

What "required margin" actually means

Margin is the good-faith deposit your broker sets aside while a leveraged position is open. It is not a fee and it is not lost — it is collateral that returns to your free balance when you close the trade. Leverage simply controls how small that deposit is relative to the full notional value you control. At 1:500, you put up 1/500th of the position's value; at 1:100, you put up 1/100th. This calculator turns those ratios into an exact cash figure so you know how much equity a trade ties up before you click buy.

The formula

The tool computes margin in two steps:

marginPerLot   = (contractSize × price) / leverage
requiredMargin = marginPerLot × lots

• contractSize is the units in one standard lot — 100,000 of the base currency for standard FX pairs.
• price is the current market rate of the pair.
• leverage is your account's ratio expressed as the second number (1:500 → 500).
• lots is your position size in standard lots (0.10 = a mini lot, 0.01 = a micro lot).

The numerator contractSize × price is the notional value of one lot — the full size of the exposure. Dividing by leverage scales that down to the slice you actually fund. Note that required margin is denominated in the quote currency of the pair (the second currency); if that is not your account currency, your broker converts it at the prevailing rate.

Worked example

You want to open 2 standard lots of EUR/USD with the price at 1.1000, on an account with 1:500 leverage.

1. Notional per lot = 100,000 × 1.1000 = 110,000 USD
2. marginPerLot = 110,000 / 500 = 220 USD
3. requiredMargin = 220 × 2 = 440 USD

So you control 220,000 USD of EUR/USD exposure while only 440 USD of your equity is locked as margin. Drop the leverage to 1:100 and the same trade demands 110,000 / 100 × 2 = 2,200 USD — five times more collateral for identical exposure. That contrast is the whole point of running the numbers first.

Edge cases and pitfalls

Quote-currency conversion. Required margin comes out in the quote currency. For EUR/USD it is already USD, but for EUR/GBP it is GBP and for USD/JPY it is JPY. If your account is in USD, the broker converts that JPY or GBP figure at the live rate, so the dollar amount you see can drift slightly from a back-of-envelope estimate.

Margin held ≠ margin you should use. This figure is the minimum to open the trade, not a safe sizing target. If you commit most of your equity as margin, a modest adverse move can trigger a margin call or stop-out. Keeping free margin as a buffer is how you survive volatility — pair this tool with a position-size calculator so risk, not just margin, drives your lot size.

Leverage is a ceiling, not a recommendation. A 1:500 cap lets you post less collateral; it does not make the trade safer. Higher leverage means the same price move represents a larger percentage of the margin posted. Regulators and instrument type can also cap effective leverage below your account headline — gold, indices and exotics frequently carry tighter limits than majors.

Run it on FXNX

FXNX offers leverage up to 1:500 across four account types, so you can model the exact margin a trade will hold before funding it — then open it on raw spreads from 0.0 pips with NX Pro.