Researchers studied the work of 200 of the world's most famous artists and calculated that even if they died young, the painters created their best work at a little before two thirds - 0.6198 to be precise - through their lifespan.
The figure is almost similar to the so-called "golden ratio" or Fibonacci code - 0.6180 - which has long been associated with optimal proportions in science and art, scientists said.
The study, which involved calculating the auction room sales records of artists since Goya, found that the average age at which they produced their most valuable work was 42, the 'Sunday Times' reported.
Monet, who died at the age of 86, was 60 when he painted what became his most valuable work, which sold in 1998 for 19.8 million pounds, the report said.
However, this figure is skewed by Old Masters who died at a young age, so this led the scientists also to calculate the point during artists' lives at which they flourished and produced their best work.
"The average age may be 42, but more important is the relative age given the lifespan of the painter," said mathematician Philip Hans Franses of the Erasmus School of Economics in Holland.