Call it a day Informal

To decide to stop working on something, at least for the rest of the day — whether because the task is finished, everyone is tired, or progress has stalled.

It’s a deliberately neutral, no-blame way to end things: nobody is failing by calling it a day, they’re simply acknowledging that the current session is over.

The phrase grew out of 19th-century American labor speech, where workers who quit partway through a shift would “call it a half day” to formally mark that they were being paid for, and stopping at, only half a day’s work. Over the second half of the century the qualifier was dropped, and “call it a day” came to mean simply declaring the day’s work finished, whether at the usual hour or early. A parallel form, “call it a night,” emerged in the early 20th century for evening activities specifically, splitting the original expression into a daytime and a nighttime version that are still used according to the time of day.

We’ve been at this for six hours — let’s call it a day.

The painters called it a day once the rain started.

I think I’ll call it a day and finish the report tomorrow morning.

A: “Should we keep debugging?” B: “No, let’s call it a day, we’re both too tired to think straight.”