In for a penny, in for a pound is a proverbial expression indicating that one should not take half-measures and should go all the way.
The saying is often used as an educational tool to lecture people about committing to their work.
It also indicates that you should not do anything half-heartedly.
We know that the expression was coined in Great-Britain somewhere during the 17th century, but its exact origin is currently unclear.
One of the earliest instances of in for a penny, in for a pound being used in writing can be tied to the writer Thomas Ravebscroft. He used the proverb in his 1695 play “Canterbury Guest”.
British writers and authors have been using the expression as a favorite ever since.
Oscar Wilde has used in for a penny, in for a pound in 3 of his novels: Nicholas Nickleby, Oliver Twist, and The Old Curiosity Shop.
But the term is used outside of literature circles as well. It is well-known for the average speaker and frequently appears in everyday informal language.