About how much longer were Lovelace's notes than her translation?

Ada Lovelace’s notes were about three times longer than the translation they accompanied. The translation was Luigi Federico Menabrea’s 1842 French account of Charles Babbage’s proposed Analytical Engine.

Lovelace translated Menabrea’s paper into English for publication in 1843, but she did far more than render the text in another language. At Babbage’s suggestion, she added seven substantial notes, labelled A through G, explaining the machine’s architecture, operation, and possible uses.

Her notes included the famous Note G, which described a method for calculating Bernoulli numbers with the Analytical Engine. Because the machine was never completed, the procedure could not be run on the original hardware, but it is widely regarded as the first published computer program.

The comparison is sometimes misstated as saying that each individual note was three times the translation’s length. The more accurate meaning is that Lovelace’s notes, taken together, were roughly three times the length of Menabrea’s original article.