Volume Delta

Volume Delta represents the difference between the pressure exerted by buyers and sellers in the market. It is calculated by subtracting the volume traded at the bid price from the volume traded at the ask price.

The Volume Delta indicator presents the cumulative number of transactions taking place on both bid and ask within a specified time frame. It shows the absolute value of the net difference between bid and ask volumes. The color representing the higher value, whether it's bid volume (green) or ask volume (red), is displayed on top of the total volume.

Volume Delta oscillates around zero.
A Delta value of zero indicates that the buying and selling pressures are balanced within the given candle.
A positive Delta indicates a larger volume of aggressive buying at the ask price resulting from trades executed by aggressive sellers.
On the opposite, a negative Delta signifies a higher volume of aggressive selling at the bid price resulting from trades executed by aggressive sellers.

In TabTrader, the Volume Delta is utilized in additional tools, such as Cumulative Delta and Volume Delta + Volume. 

Formula

Bid/Ask Volume = Number of transactions at the bid and the ask

Bid/Ask Volume Actual = Number of assets traded at the bid (BVol) and the ask (AVol)

Additional display line = | BVol - AVol |, color represents whichever is greater (BVol or AVol)