Maintenance Margin Rate: Liquidation Formulas, Tiers, and Deductions

You may hear that 20× leverage means liquidation after a 5% adverse move. In practice, it can happen around 4.5%. Maintenance margin rate accounts for that 0.5% difference.

There Are Two Kinds of Margin

A futures position has two margin amounts with different purposes.

Initial margin is money required to open the position. It equals notional divided by leverage: the amount meant when someone says “$40 for one contract.”

Maintenance margin is the minimum that must remain to keep holding the position. If accumulating losses reduce margin below it, the exchange forcibly liquidates the position.

The maintenance margin rate, or MMR, expresses that minimum as a percentage of notional. At 0.5% MMR, a $30,000 position requires $150 to remain alive.

You start with $1,500. After losing $1,350, the remaining $150 touches the maintenance threshold. The position ends there; the exchange does not wait until every dollar is lost.

Where MMR Enters the Liquidation Formula

For an isolated-margin long, an approximate liquidation price is:

The theoretical total-margin-loss price at 20× is $57,000, a 5% decline. Actual liquidation occurs $300 higher, at $57,300. The 0.5% MMR brings liquidation closer.

Reverse the signs for a short.

Entry and liquidation fees, plus unsettled funding, also come out of margin, bringing the actual liquidation price slightly closer. A liquidation calculator may differ from the exchange display by a few dollars because of fee treatment. Allowing room around liquidation is more practical than trying to eliminate every small discrepancy.

MMR Is Not Fixed: Position-Size Tiers

This is frequently overlooked. Exchanges raise MMR as position notional grows. Liquidating larger positions requires sweeping deeper through the order book and exposes the exchange to greater risk.

The following hypothetical table illustrates the structure. Actual thresholds and rates vary by exchange and asset, so check the asset's tier table before trading.

Even at the same entry and leverage, position size changes liquidation distance.

A particularly dangerous case is starting in tier 1 and crossing into a higher tier through averaging down or additional entries. It is easy to expect more quantity to move liquidation farther away, but the accompanying MMR increase can instead bring it toward the current price. This often explains why lowering average entry does not lower liquidation as much as expected. When planning staggered buying or averaging down, check the tier of the final notional in advance.

Higher tiers also lower maximum leverage. If you keep increasing a 20× position and hit the tier-3 cap, the exchange may reject additions or forcibly reduce leverage.

Maintenance Amount: Why Tier Boundaries Do Not Create Abrupt Jumps

Applying the higher MMR to an entire position just because it exceeds a boundary by $1 would abruptly raise maintenance requirements and liquidate otherwise healthy positions. Exchanges prevent that with a maintenance deduction, similar to a progressive income-tax deduction.

Apply it to a $300,000 position.

If displayed maintenance margin is smaller than “notional × MMR,” the deduction explains it. It allows liquidation price to move gradually across a tier boundary instead of jumping. It still moves, however: the unfavorable change is gradual, not absent.

When Does Margin Ratio Become Dangerous?

The ratio shown in a position window commonly means:

Some exchanges invert the formula, so a lower number is more dangerous. Misreading the direction can make liquidation appear safe. First establish whether risk increases toward 100 or toward zero.

For the 100%-threshold convention, waiting until the ratio exceeds 50% is already late in practical terms. The choices then are adding margin, partially closing, or closing completely, and rushing any of them makes matters worse. Put your stop well before liquidation; treat liquidation as the final net if the stop fails.

What Differs Between Isolated and Cross Margin?

The maintenance calculation stays the same, but its denominator changes.

Isolated margin counts only funds allocated to that position. Its liquidation price is set at entry and stays independent of other positions and wallet funds. The loss ends with the allocated amount.

Cross margin uses the entire account's equity. More balance moves liquidation farther away; losses on other positions pull even an untouched position's liquidation closer. It is a continuously changing value. See isolated vs. cross margin.

A common cross-margin misunderstanding is that lowering leverage from 20× to 10× changes an existing position's P&L and liquidation price substantially. They remain almost unchanged because the setting changes locked margin, not exposed notional. This is why risk should be assessed by notional rather than the setting alone. Read leverage ratios and liquidation distance alongside this explanation.

Three Checks Before Opening

1. What is the MMR for this asset and size? Check the tier table in the exchange's futures specifications. Altcoins commonly have much higher MMR than BTC and therefore closer liquidation prices.

2. Which tier will the final notional reach after additions? If planning to average down, calculate from the final position. A higher tier brings liquidation closer.

3. Is there enough distance between the stop and liquidation? If they sit together, brief slippage or a wick can turn a planned stop into liquidation. Liquidation has higher fees and makes remaining margin harder to recover.

The same arithmetic explains the danger of 100× leverage. Margin reaches zero after a 1% adverse move, but subtracting 0.5% MMR means the position actually ends after 0.5%. Add the spread and fees, and it can be within liquidation range immediately upon entry.

Three Key Points

① MMR is the minimum remaining-margin proportion required to maintain a position. It brings liquidation closer: at 20×, the example's actual distance is 4.5%, not 5%.
② MMR rises in tiers as notional grows. Averaging down can bring liquidation toward the current price.
③ Displayed maintenance margin includes a deduction and is therefore smaller than “notional × MMR.” First check which direction of the margin ratio means greater danger.

Notice

The tiers, MMRs, deductions, and prices are hypothetical values illustrating calculation structure, not actual figures from a particular exchange. Values differ by exchange, asset, and date; check the applicable tier table before trading. Liquidation formulas are approximations excluding fees and funding, and may differ from actual liquidation prices. Leveraged trading can lose all principal. Investment decisions and responsibility are yours.