The same buy signal in copy trading can lead to a position size of 5% of capital on one account and 40% on another. The direction and entry price will match, but the load on the accounts will not.
This happens when copying a trade but skipping the calculation: how much money can be lost, what nominal withstands this limit, and how much room remains until liquidation.
How to calculate position size before choosing leverage
Leverage is often perceived as a position size control: set 10× instead of 5× and get a bigger trade. This approach is not suitable for risk management.
Suppose the account has 10,000 USDT. One trading idea allocates 100 USDT risk, and the planned exit is 2% from the entry. For a simple linear USDT-margined position, a rough nominal calculation before commissions and slippage looks like this:
100 USDT / 0.02 = 5,000 USDT
At 5× leverage, this position requires about 1,000 USDT initial margin. At 10× — about 500 USDT. But a 2% price move with the same nominal will still result in approximately 100 USDT result change. Leverage changed margin requirements, not the selected monetary risk.
Therefore, the working sequence is simple: first the monetary limit and exit point, then nominal, and only then leverage. The calculation should include a margin for commissions, slippage, quantity rounding, and possible price gaps.
| Step | What to determine |
|---|
| 1. Risk limit | How many USDT is acceptable to lose on one trading idea |
| 2. Exit point | At what price movement the scenario stops being valid |
| 3. Position size | What nominal fits into the set monetary risk |
| 4. Leverage | How much initial margin will be required for this nominal |
Why copying ratio alone is insufficient
The trader and subscriber almost never have matching account conditions. Capital, free margin, already open positions, maximum leverage per instrument, and even minimum quantity steps differ.
There is also a less obvious problem: several small trades can become one large bet. For example, three strategies simultaneously hold longs on assets moving almost identically. Individually, positions seem moderate, but together they occupy too large a risk share.
Before starting copying, it is worth answering several practical questions:
- What amount is allocated for copying in general;
- How much is acceptable to lose on one idea;
- What is the overall limit on all open positions;
- How deals in one direction and related markets will be accounted for.
A trader's past profitability does not answer these questions. It also doesn't guarantee that the subscriber will get the same result: entry price, liquidity, commissions, and account conditions vary.
Liquidation is an emergency boundary
It is better not to use liquidation as a planned exit. The criterion depends on margin mode and exchange rules. With isolated margin, it usually triggers when the mark price reaches the calculated liquidation price. With cross or portfolio margin, the platform may assess the maintenance margin level of the entire account and start liquidation upon reaching a set threshold; the mark price participates in position valuation. The boundary is also influenced by position size, balance, and contract conditions. Increasing nominal may move the position into a different risk category where maintenance margin requirements are higher.
In isolated margin mode, separate margin is allocated for the position, although automatic replenishment can change this boundary. In cross margin mode, positions use the total available balance. Loss on one decreases buffer for others, so the displayed liquidation price can change even without position changes.
The popular estimate of 1 / leverage doesn't give an accurate liquidation price. It doesn't consider commissions, maintenance margin, risk categories, mark price, or exchange rules. The higher the effective leverage, the less room there is for error.
After execution, the calculation needs to be verified
Even a good plan remains just a plan until the order is executed. After entry, compare the calculated and actual nominal, average price, unfilled volume in open orders, margin mode, and current buffer before liquidation.
After timeout, partial fill, cancellation or resubmission of an order, first restore the real account state. This is covered in the article about reconciling orders and positions.
Order size also affects the result. A separate measurement analysis shows how nominal changes the model VWAP using order book snapshots. This is a model, not actual CopyTrader executions, but it clearly shows why a margin is needed in the calculation.
Finally, it is worth checking leverage, position mode, and margin type on related accounts. The reconciliation mechanism is described in the article on synchronizing settings before copying.
Leverage should be the last number in the calculation, not the first. First decide how much money can be lost and where to exit. Then calculate the position and check if it has enough buffer before the emergency boundary.
This material is educational and not investment advice. Trading derivatives with leverage can quickly lead to loss of funds. Formulas and interfaces vary by exchanges and contract types; check current rules of your platform before trading.
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