About 725,000 student volunteers give time worth about £175m a year, according to a new report from the National Union of Students.
The report, released to coincide with Student Volunteering Week, which starts today, says that about a third of students devote on average about 44 hours a year per person to volunteering.
The data was collected by research by the NUS between July and December, including an online survey of 2,000 students and a series of telephone interviews with key people in the student volunteering scene.
When asked why they volunteered, 78 per cent of respondents to the survey said they wanted to "improve things or help people". Two-thirds said it was a good way to develop skills.
The 69 per cent of respondents who did not volunteer said the major barrier was not having enough time.
Eighteen per cent of all students said they did not think they could afford to do more volunteering than their current levels.
The £175m figure was worked out by multiplying the number of hours volunteered by the minimum wage figure of £5.03 an hour for people aged between 18 and 20.
Student Volunteering Week, which runs until 2 March, asks students to participate in campus events and programmes in their local community.
The students will work with a range of charities from local food banks to national organisations such as the children’s charity Barnardo's.
Raechel Mattey, vice-president of the NUS, said the research confirmed that student volunteers were "contributing to their communities in a very positive way".
Nick Hurd, the Minister for Civil Society, said: "Volunteering can be a hugely beneficial way to gain experience and develop skills and it’s good to see that students across the UK are embracing it as a way to develop themselves alongside their education."