Favourite backtesting tool

I was wondering what tool/site people use.

I bring the data I need in and calculate what I require. I figure I should just trust one of the tools and save myself some time.

 

History.
But the conundrum is history is no guarantee for the future.........

 

I have been using sharesight.com.au lately and it is great for putting in backdated buys to see the performance over time in a "what-if" sort of way. You can also set it to automatically re-invest all dividends. Still getting acquainted with it but it has been really useful thus far.

 

Thanks Pier1. Agree. Better to be informed though.

 

Thanks Izzy, Ive had that suggested for tracking purposes before. Ill check it out with backtesting in mind.