The phrase is credited to Seneca The Younger around 4BC to AD65. Among other interests he was a philosopher.

When you translate literally you get: to err is human, to persevere (in the error or mistake) is diabolic ( from the word devil in latin), you can also use for diabolic one of the many synomyms: evil, devilish, atrocious.

The official translation is : to err is human to persist is of the devil.

Having studied latin for a number of years, one has to remember that a translation is a translation in the sense that the translator tries to render the thought or phrase with the most universal coverage and with the highest comprehensibility so that everyone understands with clarity the real meaning.

One can use the translation you have used as it is clear in it's meaning and I for one I do like it. It refers clearly to your mistake and is very specific about what one should avoid, that is to not repeat the same mistake twice. Well done.

If I am talking about an error or a mistake: my translation would be: to make a mistake is human, to continue to make the same mistake over again is atrocious (or a bit harsher, I would say stupid).

If I am talking more generally, such as a wrong choice of path in life or a false deduction, I would use a more universal translation that applies to all of the meanings implied in the latin phrase and I would translate by: to err is human and to continue to err is evil.

Evil in the sense of demoniac, crazy, insane or even deranged.

With this explanation, hicetnunc and all of the other commentators I invite you to try your own free translation of "errare humanum est, perseverare diabolicum"

I am positive that we will get many very good and even original translations.

Have all a beautiful day!

I'm sitting her in Dozyland chuckling over that one.

Short and sweet!  Nice finish.