Timeframes (Data Intervals)

The timeframe, or data interval, represents the price/trade action within a bar (from  the open to the close) and is expressed either in terms of time (1 minute, 30 minute, daily, etc.) or trading activity (tick count or volume). For example, in a daily chart each bar interval represents the price action of one day - the bar opens in the morning with the beginning of the trading session and closes at the end of the trading session in the afternoon, and so on for each bar. However, you can use any interval for your chart including non-time-based intervals. There are three types of data intervals: time-based, tick-based, and volume-based.

Data (Bar) Interval

Data interval, or bar interval, refers the units into which price data is segmented in an analysis window. For example, a five minute chart consists of bars that is built from 5 minutes of trading activity. By contrast, a daily chart contains bars that each represents trading activity from the beginning of the days trading session to the close of the trading session. In addition to time-based intervals, you can also specify bar intervals based on a specified number of ticks or amount of volume.

Time Stamp

Each data interval (bar) for a given symbol is time stamped with the closing time/date of the interval and summarizes the market activity (prices, volume, trades) that is used to build the bar from the open of the interval to its close. For example, with a 5 minute data interval on an equity symbol, the first bar of the day session would begin building when the session opens, and would include market activity (prices, volume, etc.) for the first 4 minutes and 59 seconds in the market. The bar is time stamped with the its close time, which never changes, which also means it does not reflect the current time.

As an example, for a daily trading session that starts at 9:30 and ends at 4:00 here are examples of bars for selected intervals:

Interval Occurrence Time Stamp Built Using
1 Minute First Bar 9:31 Market activity from 9:30:00 am to 9:30:59
  Second Bar 9:32 Market activity from 9:31:00 to 9:31:59
  Last Bar 4:00 Market activity from 15:59:00 to 15:59:59
5 Minute First Bar 9:35 Market activity from 9:30:00 to 9:34:59
  Second Bar 9:40 Market activity from 9:35:00 to 9:39:59
  Last Bar 4:00 Market activity from 15:55:00 to 15:59:59
Daily Single Bar 4:00 Market activity from 9:30:00 to 15:59:59