You have got the scale in reverse. From the article : "The score is essentially runs/second: the number of times you can run the benchmark in one second. For a

You have got the scale in reverse. From the article : "The score is essentially runs/second: the number of times you can run the benchmark in one second. For all scores, bigger is better" So, no, dart2js is actually slower than hand written javascript code, which is in turn slower than dart code running on the dart VM. EDIT : I got it all wrong, sorry, didn't see the far end of the graph.