失之毫厘，差以千里

失之毫厘，差以千里

Literally means:

a difference of centimetres will make a difference of thousands of miles

Actually means:

a small discrepancy leads to a great error

失 refers to mistake or error; 毫, 厘, 微 are minute units for length; 千里 is 1.5 million times of one Li.

The phrase means that a minor mistake may result in a huge problem. It is used to remind people to be conscientious and careful. Derogatory.

失，差错，失误。毫、厘，微小的长度单位。千里，一厘的一百五十万倍。

失之毫厘，差以千里，指起初出了小差错或稍微有点偏差，结果就会造成很大的错误。强调做事要认真，不能有一点点差错，否则会有很大的损失。具有贬义色彩。