While child labour has always been an important part of the industrial revolution story, there is little quantitative evidence about the number of child workers in the 1740–1850 period. This article estimates trends in the percentage of the agricultural day-labouring workforce that were children. By using the wage level to identify child workers, it is possible to estimate child labour for a large sample of English farms. It is found that girls were rarely employed as day-labourers, while boys were employed about as frequently as women. The percentage of boys in the day-labour workforce increased until the 1820s and then declined.