Position sizing

The calculation

risk amount   = balance × risk per trade (%)
ticks to stop = |current price − stop loss| / tick size
risk per lot  = ticks to stop × tick value
lot size      = risk amount / risk per lot

The result is then multiplied by the Ratio of the account link (if you set one) and clamped between your channel's Min Lots and Max Lots, rounded to two decimals; the broker's own volume limits still apply on top. The clamp is not a risk check: if the stop is so wide that the formula asks for fewer lots than Min Lots, the order goes out at Min Lots and risks more than your percentage (you get a notification), and above Max Lots it goes out at Max Lots and risks less. Risk-Based is one of three Position Sizing Methods; Fixed Percentage and Fixed Lots ignore the stop distance.

A worked example

Balance           10,000 USD
Risk per trade    0.5%          → 50 USD at risk
Signal            BUY EURUSD 1.0850, SL 1.0800
Stop distance     0.0050        → 50 pips
Pip value         10 USD per pip per standard lot

lot size = 50 / (50 × 10) = 0.10 lots

Why metals and indices trip people up

Contract size differs per instrument and per broker. Gold is often 100 ounces per lot, an index CFD might be 1 or 10 contracts per point, and micro variants divide everything by ten. Sizing from a forex assumption on a gold signal is how a 0.5% risk becomes 5%.

• PipSync reads tick size, tick value and contract size per symbol, from your own account where your platform provides it and otherwise from PipSync's shared MT5 service.
• Suffixed symbols (.m, micro) carry their own specs — re-check sizing when you trade a suffixed variant.
• If no spec can be read, a currency pair is sized with the standard forex contract and every other instrument goes out at your Min Lots. If your account returns contract data that cannot be used, a Risk-Based or Fixed Percentage trade is skipped with the notice "contract data unusable"; Fixed Lots is not affected.

Margin and free equity

Sizing is about risk, but the broker also needs margin. A correctly-sized position can still be rejected for insufficient free margin when several trades are already open.

• Max open positions is the practical margin control — cap the book, not just each trade.
• Watch free margin during high-volatility sessions; floating loss eats it before any stop is hit.
• Rejections for margin appear in the trade log with the broker's own message.