Used Margin Explained: Why Your Trades Get Blocked

Used Margin Explained

Meet Dave. Two thousand dollars sitting in his EUR/USD account. Three trades already open, all doing fine. He spots a fourth setup, clean, textbook, exactly the kind of trade he's been waiting for. He clicks buy, and the platform throws back an error: insufficient margin. He checks his balance. It still reads two thousand dollars, untouched. So what just blocked him?

Nothing got closed. Nothing got lost. And yet the platform is telling him he can't afford a trade he clearly has cash for. The answer isn't hiding in his balance at all, it's in a number most new traders never even look at: Used Margin.

Required Margin — One Trade

Quick recap so nothing here feels new. Every time you open a single position, your broker sets aside a slice of your balance just for that trade — that's Required Margin. It's calculated from the lot size, the instrument's contract value, and the leverage your broker offers, and it varies pair to pair and account to account, so it's always worth checking your own broker's margin schedule before sizing up.

Say Dave opens one EUR/USD trade and it locks up two hundred dollars. That two hundred isn't gone, it isn't a fee, it's parked. The instant he closes that trade, it's released straight back to him. One trade, one number, one lock. Simple so far.

But Dave doesn't run one trade at a time — he had three open when he tried that fourth entry. So here's the question a simple recap can't answer: if every trade locks up its own little slice, what happens to your account when three, four, five of those slices are locked up at once? That's where this stops being simple.

Three Trades, One Account

Here's Dave's actual account the moment before that fourth click. None of these trades talk to each other — each one only knows its own slice. But your broker doesn't care that they're separate; it adds every single one of those slices together and locks that whole combined amount away from you.

Two hundred, plus one hundred fifty, plus two hundred. That total, five hundred fifty dollars, is what actually gets subtracted from what Dave can use. That combined number — the sum of every Required Margin across every open trade — is Used Margin. It's not a fee, it's not lost money, it's just unavailable, for as long as those trades stay open. And unavailable money can still block a perfectly good trade.

Your Turn

Pause here and try it on your own account, real or demo. Open your trade list, and for every position currently live, find its Required Margin. It's usually sitting right there in your trade panel, sometimes labeled 'margin,' sometimes shown per position. Add every single one of those numbers together, in your head or on paper. That total is your Used Margin.

Got a number? Good, hold onto it. Because here's the relationship in one sentence: Required Margin belongs to one trade. Used Margin belongs to your whole account. One is a single brick. The other is the entire wall built from every brick you've stacked so far.

• Add a trade → the wall grows
• Close a trade → the wall shrinks
• Only one trade open → Required Margin and Used Margin are, for now, the exact same number

Used Margin Calculation

Let's put that relationship into a formula you can actually use, not just a feeling.

Ten open trades means ten numbers added together. One open trade means the formula collapses down to just that one number. It doesn't matter what pair each trade is on, what direction, what timeframe — the formula doesn't ask any of that. It only asks: is this position still open? If yes, its Required Margin gets added to the pile. If it's closed, it drops out of the sum completely, the second you close it.

Balance, Used Margin, Free Margin

Now here's where Dave's confusion actually gets solved. Your account balance is the full pot of money you deposited, plus or minus whatever you've realized. Used Margin is the slice of that pot currently locked across every open trade. Subtract one from the other and you get what's actually available to open something new — your Free Margin.

Dave's balance said two thousand. His Used Margin was five hundred fifty. That leaves fourteen hundred fifty dollars technically free. So why did his fourth trade still get rejected? Because that new trade needed more Required Margin than his fourteen hundred fifty could cover, once you factor in leverage and lot size on top of it. Balance alone told him nothing. Free Margin was the number he needed — and that's the number that saves an account before a margin call ever shows up.

Spotting It Live on EUR/USD

Let's take this onto a real chart. As of writing, EUR/USD is trading around 1.1587–1.1602, holding near its August peak after a modest monthly gain of roughly 1.5%. That kind of steady range is exactly where margin mistakes creep in quietly — the price isn't crashing, so traders forget to check what's locked up behind the scenes.

Here's how you'd hunt for this in real time: pull up your open trades panel side by side with the chart, and before you even look for a signal, calculate your current Used Margin and Free Margin first. Now say the chart hands you a bullish engulfing candle at a clean support level — that's a simple, bullish, reversal pattern. Classic frame: your entry trigger is a close back above that engulfing candle, your stop sits just under the wick with a little wiggle room so normal noise doesn't tag you out, and your target is set at a two-to-one reward against that risk.

But here's the real point: where this candle shows up on the chart matters more than the shape of the candle itself. And even a perfect signal is worthless if your Free Margin can't cover it. The pattern can be flawless and still fail — the stop is what saves you when it does.

The Margin Call Moment

So back to Dave. Three trades open, five hundred fifty locked as Used Margin, fourteen hundred fifty sitting as Free Margin. His fourth trade, at the lot size he chose, needed Required Margin higher than that Free Margin could cover. His platform did exactly what it's designed to do — it protected him from opening a position his account genuinely couldn't support.

This is the same mechanism behind a margin call, just one step further down the line. Most brokers set a margin call level (commonly around 100% of Used Margin) and a harder stop-out level (often 20–50%, depending on the broker) where they start force-closing positions automatically to protect both you and them from a negative balance.

Recap: Used Margin

Used Margin is simply the sum of Required Margin across every position you currently have open. It's not lost money, and it's not a fee — it's your own capital, temporarily reserved. The moment a trade closes, its slice comes back to you. But while trades are open, that locked total quietly shrinks what you can actually deploy next, no matter how healthy your balance looks.

• Required Margin = the lock for one single trade
• Used Margin = the sum of every Required Margin across all open trades
• Free Margin = Balance minus Used Margin — this is what you can actually trade with
• A rejected trade almost never means you're broke — it means Free Margin ran out
• Falling Free Margin, driven by rising Used Margin or floating losses, is what eventually triggers a margin call

Dave's account was never in danger of losing money that day — his platform simply refused to let him overextend it. Understanding Used Margin turns that 'insufficient margin' error from a confusing wall into a number you can calculate, predict, and plan around before you ever click buy.