Work out volunteer requirement instantly with clear inputs, formula shown and shareable results.
Shifts per role round the coverage hours up to whole shifts, the total shifts multiply that by the roles, and a reserve percentage is added for no-shows. Volunteer no-show rates of 15 to 25 percent are normal, so recruiting exactly to the shift count reliably leaves gaps on the day.
Volunteers needed
volunteers = ceiling(roles x ceiling(hours per role / shift length) x (1 + reserve))
volunteers = ceiling(roles x ceiling(hours per role / shift length) x (1 + reserve)). Shifts per role round the coverage hours up to whole shifts, the total shifts multiply that by the roles, and a reserve percentage is added for no-shows.
Volunteer no-show rates of 15 to 25 percent are normal, so recruiting exactly to the shift count reliably leaves gaps on the day.
Enter roles to cover, hours each role must be covered, length of one volunteer shift, reserve allowance for no-shows. The defaults shown are a realistic worked example — swap in your own figures to get a result you can use.