I'm looking at the RSI for AAPL and noticed an approximate 20 point difference between Google's and Yahoo's RSI. Are they using two slightly different versions of RSI? Or is there some sort of time delay between the two sites? It seems like a fairly large difference is why I ask.

Google Finance's RSI: 28.23

Google Finance RSi for AAPL RSI

Yahoo's RSI: 51.31

Yahoo Finance RSI for AAPL

2 Answers 2


Google's RSI is using a 10 period on 2 minute bars - i.e. it is based upon the last 20 minutes of data.

Yahoo's RSI is using a 14 period lookback on an undetermined timeframe (you could maybe mouse-over and see what incremental part of the chart is giving) and given the "choppier" price chart, probably 30 second or 1 minute bars.

Given the difference in both the period specified and the periodicity of the charts - you should expect different results.


Look at the 'as of'. Google's as of is 11:27 whil Yahoo's is 11:19. Given the shape of the Google curve, it looks to me that Yahoo's may well drop that much in the next 8 minutes.

In fact, looking at it now, Yahoo's algorithm showed it as about 30 at 11:24, before going back up again some. It may not have been identical to Google's, but it was certainly close.

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