Why is VWAP sometimes different between a 1-minute chart, a 5-minute chart, and/or Montage?

DAS Trader Pro calculates VWAP in 2 different ways. On the Montage, the VWAP is calculated by using every intraday price tick and weighting by volume. This is usually the textbook definition of VWAP and is what pro terminals like Bloomberg use. The charts, on the other hand, weights the volume during each candle against a price calculated using the (high+low+close)/3 of that candle. This is why for particularly volatile stocks, you’ll see discrepancies across time frames. If in doubt, use the Montage’s value.