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Trading Infrastructure

Trade Copier Lot Sizing: The Five Modes and How to Choose

Fixed lot, lot multiplier, balance %, equity %, fixed risk % — five ways a trade copier can size positions across follower accounts. Each one translates the master's lot size differently, and the mode you pick sets the risk on every account.

9 min read

Why Lot Sizing Mode Matters

A trade copier does not copy lot sizes. It translates them. A 1-lot trade on a $100,000 master account is 1% risk. The same 1-lot trade copied to a $10,000 follower account is 10% risk. Without a sizing step in between, the copy scales risk by the ratio of the account sizes.

The lot sizing mode is how the copier does that translation. Pick the wrong one and risk drifts apart across accounts. Pick the right one and every follower takes the same proportional exposure as the master, across account sizes and brokers. Trada exposes five modes, set per follower account, and the rest of this article covers what each does and when it holds.

Quick Answer

Balance percentage is the right default for most prop firm setups: it scales each follower's position proportionally to its account balance, so risk stays consistent regardless of account size differences. Lot multiplier works when all accounts are the same size. Fixed lot is almost never appropriate for multi-account prop firm setups.

5Sizing ModesMultiplier · Fixed · Balance % · Equity % · Risk %
1Recommended DefaultBalance % for most prop firm setups
perAccount ConfigurationEach follower configured independently

The Five Lot Sizing Modes

Lot Multiplier

The copier takes whatever lot size the master trades and multiplies it by a fixed factor.

Example: Master trades 1.0 lots. Multiplier is 0.5. Follower receives 0.5 lots.

When it works: All follower accounts have the same balance as the master account (or a known fixed proportion of it). A $50,000 follower copying a $100,000 master at 0.5x multiplier produces correct proportional risk.

When it fails: Follower balances vary. A 0.5x multiplier on a $20,000 follower and a $80,000 follower produces very different risk percentages even though the lot sizes look proportional on the multiplier.

Fixed Lot

Every trade on every follower account uses a fixed lot size you define, regardless of what the master trades.

Example: Master trades 2.0 lots. Fixed lot is set to 0.1 lots. Every follower trades exactly 0.1 lots.

When it works: Very small evaluation accounts where the minimum lot size must be enforced regardless of master sizing, or testing a copier configuration before going live.

When it fails: Almost every real multi-account setup. Risk as a percentage of account balance will differ across accounts and will not track the master's intended exposure.

Balance Percentage

The copier calculates follower lot size as a percentage of the follower's account balance, scaled relative to the master's balance.

Formula: Follower lot = Master lot × (Follower balance / Master balance)

Example: Master trades 1.0 lot on a $100,000 account. Follower has $25,000. Follower receives 0.25 lots. The risk percentage is identical on both accounts.

When it works: Multi-account setups where followers have different balances. This is the standard mode for prop firm traders managing accounts of varying sizes across multiple firms.

When it fails: It does not fail in normal use. The main edge case is an account with balance near zero (closed losses accumulate), which would produce near-zero lot sizes. Monitor balance levels across followers.

Equity Percentage

Similar to balance percentage, but uses current equity (balance ± open P&L) instead of closed balance.

Example: Master has $100,000 equity and trades 1.0 lot. Follower has $23,000 equity (balance was $25,000 but has $2,000 in open loss). Follower receives 0.23 lots.

When it works: When you want position sizes to track current account state — shrinking during drawdowns, expanding during winning streaks — without touching the configuration.

When it fails: Equity moves with every tick on open positions. A position opened during a drawdown comes out smaller than it would under balance %. Open several trades in sequence during a losing streak and each is smaller than the last, compounding the reduction in the direction you may not want.

Fixed Risk Percentage

The copier calculates lot size so that if the trade hits its stop-loss, the loss equals a defined percentage of the follower's account balance.

Formula: Follower lot = (Account balance × risk %) / (Stop-loss distance in pips × pip value)

Example: Follower has $25,000 balance. Risk is set to 1%. Stop-loss on master is 20 pips. Lot size calculated so 20-pip loss = $250 (1% of $25,000).

When it works: The tightest risk control of the five. Every trade is sized to lose the same percentage of account balance if stopped out, whatever the master's stop-loss distance.

When it fails: It requires a stop-loss on the sender order. If the master trades without a defined stop — runs wide stops, adds to losers, or uses trailing stops that move — the calculation has no distance to resolve against, and lot size falls back to a default.

Which Mode for Which Setup

Setup TypeRecommended ModeWhy
Multiple prop firm accounts of different sizesBalance %Proportional risk across all account sizes without manual recalculation
All follower accounts are the same size as masterLot Multiplier (1x)Simplest configuration when account sizes match
Evaluation account (minimum lot enforced)Fixed LotOverride proportional sizing when broker minimums apply
Strategy with consistent stop-loss disciplineFixed Risk %Most precise risk control — requires stop-loss on every trade
Accounts with active drawdown managementEquity %Position sizes shrink automatically during losing periods

Lot Sizing and Prop Firm Rules

Prop firm accounts add one constraint that changes the calculus: the daily loss limit. The lot sizing mode sets how far a single adverse trade can move a follower account relative to that limit.

Sizing Mode
Risk Predictable per Trade
Scales with Account Balance
Fixed Lot
Lot Multiplier
Balance %
Equity %
Fixed Risk %

For prop firm setups, two things have to hold: risk is predictable per trade, and it scales with account balance. Fixed lot fails both. Lot multiplier fails the second. Balance %, equity %, and fixed risk % satisfy both, which leaves them as the appropriate choices for accounts with daily loss rules.

Set your lot sizing mode before setting your daily loss protection thresholds. If lot sizing is wrong, even correctly configured protection thresholds will fire at unexpected P&L levels because the actual risk per trade differs from your assumptions.

For more on setting daily loss and overall loss thresholds, see the trade copier risk management guide. For the full setup process across prop firm accounts, see how to copy trades across prop firm accounts.

Common Mistakes

MistakeWhy It FailsFix
Using fixed lot across accounts of different sizesRisk % is inconsistent — a 0.1 lot is 0.1% risk on $100k but 1% risk on $10kSwitch to balance % and let the copier calculate proportional sizing
Using equity % during a drawdownPosition sizes compound downward while losses are open, reducing exposure at the worst timeUse balance % as default; switch to equity % only with deliberate intent
Copying without a stop-loss and using fixed risk %Fixed risk % cannot calculate lot size — falls back to an uncontrolled defaultEnsure every master trade has a defined stop-loss before using this mode
Setting lot multiplier on mismatched account sizesA 1x multiplier on a $10k follower copying a $100k master means 10x the intended riskSet multiplier to follower balance / master balance ratio
Changing lot sizing mode on live accountsAny open positions were opened under the previous sizing — they will not be adjustedChange sizing mode only when no positions are open on follower accounts

Getting the Configuration Right

The lot sizing mode is configured per follower account. Before going live:

  1. 1Identify your master account balance and every follower account balance.
  2. 2Calculate the expected lot size ratio (follower balance / master balance) for each account.
  3. 3Select balance % for most setups. For same-size accounts, lot multiplier at the ratio from step 2.
  4. 4Place a minimum-lot test trade on the master. Verify each follower receives the expected lot size.
  5. 5Check that the expected lot size on each follower represents the same risk percentage as the master.
  6. 6Only after verification: configure your daily loss and overall loss protection thresholds based on the confirmed lot sizes.

A misconfigured mode carries the wrong risk on one or more accounts on every trade from that point forward, and open positions are not retroactively resized — the mode applies from the next trade on. The test trade costs a spread; the misconfiguration costs a funded account. Set the mode per follower, confirm it on a minimum-lot test trade, then configure protection thresholds against the lot sizes you confirmed.

Frequently Asked Questions

Sources

  1. 1.FTMO: Challenge Rules and Conditions — position sizing requirements, ftmo.com/en/rules (accessed May 2026)
  2. 2.Apex Trader Funding: Funded Account Rules — lot size and risk guidelines, apextraderfunding.com (accessed May 2026)
  3. 3.BIS Quarterly Review: Position sizing and risk management in algorithmic trading, 2023
  4. 4.Finance Magnates: Retail prop firm account disqualification causes, 2025
  5. 5.MetaQuotes: MT5 position sizing documentation, metaquotes.net (accessed May 2026)

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