Equity is the total value of your account taking into consideration all positions and settled transactions. It is calculated using the simple formula below: 👇 

Equity = Account Balance + Unrealized P&L (all positions) + Realized P&L (all positions).

To understand this better, let's say you have the following details for a trade:👇

Account balance=$50

Realized Loss=$4

Unrealized loss=$3

Margin=$10

If you are on isolated margin mode, your equity will be $50-$4-$3=$47

Notice that I subtracted the realized loss and unrealized loss from the starting account balance but if the data above had provided realized profits or unrealized profits, I would have added them to get the equity.

Margin balance in isolated mode, is arrived at by adding losses or gains to the initial margin for a particular position. It is computed using the simple formula below:

Margin Balance = Initial Margin + Unrealized Profit and Loss.

So since our margin according to the above data is $10, the unrealized profits or losses are applied to it, which means that we would have $7 as margin balance.👉($10-$3=$7)

Notice that I did not apply the realized loss of $4 to the margin, this is because the realized loss of $4 is typically settled immediately and deducted from the account balance of $50 when the trade was opened, so it doesn’t directly affect the position’s margin balance of $7 as we calculated above but it does impact the overall equity that was why when I calculated equity earlier, I did👉$50-$4-$3=$47

Notice how I subtracted it from the account balance to arrive at an equity of $47.

So, in isolated margin, equity is not the same as margin balance but in cross margin, the entire account balance is used as margin therefore any addition or  is applied to it. This means hence, that margin balance is the same as equity.