Category Archives: Leo Mattersdorf

The Hardest Thing in the World to Understand is Income Taxes

Albert Einstein? Leo Mattersdorf? Fictional?

Dear Quote Investigator: I have been struggling trying to figure out how much I owe to the Internal Revenue Service this year. The quote I would like you to explore does not sound very extraordinary. What makes it funny and outrageous is the identity of the person who supposedly said it:

The hardest thing in the world to understand is the income tax.

Did Albert Einstein really say this? I have seen this statement in many places, and the quote is even listed on the official website with an attribution to Einstein [EIS]. However, I am skeptical because no one seems to have a good reference, and the humor is too perfect.

Quote Investigator: This is a timely and entertaining query, and QI may have found the origin of this quotation. In 1963 a letter written by Leo Mattersdorf appeared in Time magazine with the following assertion: “From the time Professor Einstein came to this country until his death, I prepared his income tax returns and advised him on his tax problems.” Mattersdorf told the following anecdote about Einstein [TLM]:

One year while I was at his Princeton home preparing his return, Mrs. Einstein, who was then still living, asked me to stay for lunch. During the course of the meal, the professor turned to me and with his inimitable chuckle said: “The hardest thing in the world to understand is income taxes.” I replied: “There is one thing more difficult, and that is your theory of relativity.” “Oh, no,” he replied, ”that is easy.” To which Mrs. Einstein commented, “Yes, for you.”


Einstein died in 1955, so this story appeared after his death. Nevertheless, there is solid evidence that Mattersdorf was a friend of Einstein’s, and he performed tax accounting work for him. Here are additional selected citations in chronological order.

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