What is considered genius IQ? What was Einstein's? What is highest ever?

Anything above 140 was considered a genius according to Terman's Intelligence Scale. As for Einstein, nobody really knows his IQ as IQ test was not even made during his time. As such all his test scores were merely speculations. High IQ for adult ever recorded was that of Marilyn Von Savant, a newspaper columnist. IQ score is 230!

And depending on the scale 130 qualifies you to join Mensa. (but top 2% of any widely given standardized intelligence test works.)

This is an very old chart from 1928 as you can see a lot has changed. 175 or above Precocious 150–174 Very superior 125–149 Superior 115–124 Very bright 105–114 Bright 95–104 Average 85–94 Dull 75–84 Borderline 50–74 Morons 25–49 Imbeciles 0–24 Idiots This is a modern chart 145–160 Very gifted or highly advanced 130–144 Gifted or very advanced 120–129 Superior 110–119 High average 90–109 Average 80–89 Low average 70–79 Borderline impaired or delayed 55–69 Mildly impaired or delayed 40–54 Moderately impaired or delayed