A ‘lot’ is the measurement of volume (size of the position).
1 standard lot is equivalent to a volume of 100,000 ‘units’ having been traded.
1 unit of GBP:USD is equivalent to £1.
100,000 units (1 standard lot) of GBP:USD is equivalent to £100,000.
1 unit of EUR:JPY is equivalent to €1.
100,000 units (1 standard lot) of EUR:JPY is equivalent to €100,000.
1 unit of USD:CHF is equivalent to $1.
100,000 units (1 standard lot) of USD:CHF is equivalent to $100,000.
and so on…
Different volumes traded are denoted by different ‘lot’ sizes, called ‘standard’, ‘mini’ and ‘micro’. Let’s have a look at how many units they respectively represent, below:
MT4 ‘lot’ size
Number of ‘Units’
This is what volume looks like in your trading platform. Where 1.00 denoted 1 standard lot.
You are able to open and close different size positions, therefore manipulating your risk/exposure to the market and its movement.
Let’s have a look at an example, below.
A trader opens a long position of EUR:USD with a volume of 1 standard lot.
The trader later closes 0.4 standard lots (4 mini lots) from their open position.
Therefore, the trader now has 0.6 standard lots (6 mini lots) of their original position left open.