Forex & MetaTrader
Lot size is the volume of a forex or CFD position: a standard lot is 100,000 units of the base currency, a mini lot 0.10 (10,000 units) and a micro lot 0.01 (1,000 units); brokers set a minimum lot, a maximum lot and a lot step, and every order must be a multiple of that step.
Lot size, together with the pip value of the symbol and the distance to the stop, determines the money at risk on a trade. Because the lot step is discrete, some sizes are simply not available: a risk calculation that comes out at 0.137 lots has to become 0.13 or 0.14, and on a broker with a 0.1 step it has to become 0.1 or 0.2, which is a large difference on a small account. Multi-target signals compound the issue, since the lot is divided across several positions and each leg must still respect the minimum and the step.
AlgoVesta supports fixed lots, a percentage of balance, or a risk-based lot derived from the stop distance and the symbol's pip value, and it rounds the result to the broker's lot step within the broker's minimum and maximum. For multi-target signals the total lot is split across targets according to your allocation, each leg is rounded to the step, and the wizard shows the resulting per-leg lots before you save; if the lot is too small to split into all targets, fewer legs are opened rather than the total being increased, so the position is never larger than you approved. Brokers that use netting accounts, where same-direction orders merge, are detected and the signal is opened as a single position with the first target. See Forex on MetaTrader and multi-target signal.
A $5,000 account risks 1% per trade. A GBPUSD signal has a 40-pip stop. Risk is $50; at $10 per pip per standard lot the raw size is 0.125 lots, rounded to 0.12 on a 0.01-step broker. With three targets at 50/30/20, the legs are 0.06, 0.03 and 0.03 lots (the rounding remainder goes to the first leg), all sharing the same stop.