What is Ask and Bid?
The market always has 2 prices, just like at any bank exchange office:
The Ask price is the price at which an asset can be purchased.
The Bid price is the price at which an asset can be sold.
The Spread is the difference between the Bid and Ask prices.
For example, BTCUSD has 2 prices:
Ask $68240 - the buy price.
Bid $68230 - the sell price.
The difference between the prices is the Spread. The spread in this case is $10 (Ask price $68240 - Bid price $68230 = spread $10).
The spread is not a fixed value and can constantly change along with the prices. The spread is included in the result of your trade from the very opening.
What price is used to build a chart and how to change the direction?
There are two ways of displaying the chart: by the selling price (Bid) and by the buying price (Ask). You can always change the display mode of the chart in the terminal.
Desktop
To change the display mode of a chart on your PC, use the arrow icon showing the direction (at the top left of the chart) and select the price display type in the dropdown menu.
Mobile app
To change the display mode of a chart on the mobile app, use the arrow icon showing the direction (at the top of the chart) and select the price display type in the dropdown menu.
Key point
To avoid confusion, remember this rule:
Buy Trade
Opens at the Ask price
Closes at the Bid price
Sell Trade
Opens at the Bid price
Closes at the Ask price
Useful tips
After opening a trade, the chart is automatically displayed in the price mode at which the trade will be closed. For example, if you opened a Buy trade at the Ask price, the chart will be displayed in the Bid price type.
The end of each buy at the Ask price will be a sale at the Bid price. The exit price from a buy trade should be determined using the Bid chart only.
The end of each sale at the Bid price is a buy at the Ask price. The exit price from a sell trade should be determined using the Ask chart only.