Copy trading position sizing: why followers may trade different volumes

Equity-to-equity scaling

The cTrader Copy documentation explains an equity-to-equity model. At a high level, the copied trade size reflects the relationship between investor equity and strategy provider equity. If a provider has ten times the allocated equity, a follower’s proportional exposure can be around one tenth of the provider’s volume before platform and broker constraints.

That is not a universal equation for every platform. Some products support fixed amounts, multipliers or separate allocation rules. Never apply one product’s formula to another without its documentation.

Why small accounts face rounding problems

Suppose proportional calculation suggests a volume smaller than the broker’s minimum permitted trade. The broker can impose a minimum lot size or increment, meaning the copied order may be adjusted or not placed. cTrader explicitly documents adjustment to permissible broker volume steps in some cases.

A small allocation can therefore create fewer copied trades, a different concentration, and markedly different costs as a percentage of the account.

Deposits, withdrawals and changes in provider equity

When the provider or follower adds or removes capital, the system may need to rebalance copied positions. A deposit is not merely a cosmetic balance update; it may affect position sizes and the follower’s risk. Before copying, check how the specific service handles such events and whether adjustments involve market executions.

Practical calculation discipline

Compare the provider’s current leverage and open trade exposure to your own allocation. Estimate loss if all copied positions move against you by a plausible amount. The basic position-size calculator is useful for understanding risk budgets, but it does not replace the platform’s actual copy-sizing formula.