A Balance is the amount of money you have in your trading account. It is the amount of available funds in your account excluding any unrealized profit or loss or any possible charges for open positions. The Balance does not change during open trades. For example, if you deposited $10,000 in your trading account and then you decided to buy EURUSD with a floating profit of $1,500 then your Balance is still $10,000 until you close the position. The balance of your trading account is displayed in the Terminal Window of MT4:

In the Toolbox, if you are trading with MT5


In forex trading, the balance refers to the amount of money in your trading account after taking into account all trades that have been closed. It is the sum of your initial capital plus any profits or losses resulting from your trading activities.
For example, let's say you deposit $10,000 into your forex trading account. You then make a series of trades, some resulting in profits and some losses. For example, after closing all your trades, your account balance might now be $12,500, which means you've made a profit of $2,500.

It's essential to keep track of your account balance as it reflects the overall performance of your trading strategy. A positive account balance means you've made a profit, while a negative balance means you've suffered losses.
Note that the account balance differs from the equity, which refers to the amount of money in your account currently available for trading. This is because equity considers open positions and unrealized profits or losses. At the same time, the balance only reflects realized profits or losses from closed trades.