Flexflyer for your benefit & others on the board Ive posted this idiot link i.e. what you have to be an idiot to not know, lie about and get wrong, look and learn steviishite and jimmyriddle
This is for advfn users, as the above was specific to another data feed I use(It always classifies a trade one way or the other which makes it good)
This is how advfn calculates it
The Buy/Sell indicators are assumed. The trade price is compared to the bid/offer price to calculate the assumed direction of the trade
Volume - Shows the totals shares traded in the day. This is the sum of shares bought and sold. The Buy, Sell and unknown indicators are calculated as follows: Where the trade price is closest to the Offer price, the trade is considered a 'Buy'. Where the trade price is closest to the Bid price, the trade is considered to be a 'Sell'. Where the trade price is dead centre between the Bid and Offer, the trade is considered 'unknown', this indicates that the trade cannot be identified as either a 'Buy' or a 'Sell'.