Leverage and margin, explained: how 10× turns a 5% loss into liquidation

Leverage is the most expensive math lesson in finance. Used carefully it can multiply a small edge into a meaningful return; used carelessly it deletes accounts in a single bad week. The actual mechanics are simpler than most explanations make them sound — once you see it, the danger becomes obvious.

What leverage actually is

When you use 10× leverage to buy $10,000 of BTC, you put up $1,000 of your own money (the margin) and borrow the other $9,000 from the broker. Your notional exposure is $10,000; your equity at risk is $1,000. Every dollar BTC moves now represents ten times the move on your equity.

BTC move    Notional $10k changes by   PnL on equity    % of margin
+10%        +$1,000                     +$1,000          +100%
+5%         +$500                       +$500            +50%
+1%         +$100                       +$100            +10%
-1%         -$100                       -$100            -10%
-5%         -$500                       -$500            -50%
-10%        -$1,000                     -$1,000          -100% (liquidated)

Notice the asymmetry. A 10% favorable move doubles your money. A 10% adverse move wipes it. With higher leverage, the move that wipes you out gets smaller proportionally — at 20× you're out at -5%, at 50× at -2%, at 100× at -1%.

Maintenance margin and liquidation

Brokers don't actually let you ride to zero. Most exchanges enforce a maintenance margin — typically 0.5% to 1% of notional. If your equity drops to that threshold, they liquidate your position automatically, recovering the borrowed funds. You keep whatever's left, which is usually close to zero.

The liquidation price is computable. For a long position at 10× leverage with 1% maintenance margin, it's roughly the entry price × (1 − 0.09). Buy BTC at $50,000 → liquidation around $45,500. A 9% move down and you're done.

Isolated vs. cross margin

Two modes. Isolated margin: only the equity assigned to that specific position can be lost; if the position liquidates, the rest of your account is untouched. Cross margin: all your account equity backs every position, so a single bad trade can drain everything.

Isolated is almost always the safer default for systematic strategies. It costs you a slightly tighter liquidation point (less buffer), but it converts "blow up one trade" into "lose one allocation" instead of "lose the account."

How much leverage is actually safe?

There is no universally safe number — it depends on the asset's volatility and your stop placement. The honest framing: leverage should be sized so that your stop-loss, not your liquidation price, is what closes losing trades. If your stop is at 3% from entry and your liquidation is at 4%, you have almost no margin for slippage.

Rule of thumb: stop distance × 3 ≤ liquidation distance. If your typical stop is 3% from entry, your liquidation should be at least 9% away, which means leverage of about 11× or less on a 1% maintenance margin. For most crypto strategies that ATR-size their stops, 2-5× leverage is a sane operating range; above 10× you're betting on no slippage, no spike, no fast crash. Markets reliably deliver all three.

The better alternative

If you need more exposure than your account allows at sensible leverage, the right answer is usually "trade smaller until you have a bigger account," not "crank the leverage." The expected return per trade doesn't change with leverage; only the variance does. Higher variance + path dependency = higher probability of ruin even on a profitable strategy.

The math: a strategy with a positive expected value but high enough leverage that any single trade can wipe you out has a long-run expected outcome of zero (Kelly's argument). The optimal leverage for a given edge is much lower than what most retail brokers will let you take.

Next steps

Read the crypto position sizing post for the maths that connects stop placement, equity at risk and leverage. And risk of ruin covers what happens to expected value when variance gets too large.