What is a realized profit and loss?

Realized profit or loss is the profit or loss incurred after a Futures position is closed.

For example, if you bought 1 contract of ES for 4,100 and sold it for 4,200, your Realized Profit and Loss = (Sell Price - Buy Price) x Quantity x Contract Multiplier = (4,200 - 4,100) x 1 unit x 50 = USD 5,000.