What it means
To do your bit means to chip in and do your share, even if it's only a small bit, so the whole job doesn't land on everyone else. It's got a helpful, community feel to it, the kind of thing people say about mucking in at a fundraiser, helping neighbours out, or sorting the shared mess without making a song and dance about it.
Usage examples
"Everyone did their bit for the street party, some baked, some hung bunting, and the whole road pitched in."
"If everyone does their bit, the whole hall will be cleared in ten minutes."
"She always does her bit for the village fete without being asked."
"Come on, do your bit and stack the chairs instead of ghosting the clean-up."
"We all did our bit to get Nan's garden sorted before she came back from hospital."
Where it comes from
The phrase hangs on bit meaning your own small share of a job or duty. It became especially common in Britain during the First World War, when do your bit was used in posters and public campaigns to urge people to contribute whatever help they could to the wider war effort.
