Talk to your accountant. I would say, that for people wanting i.e. 3 day weekend, or 6 hour days, agreeing on the 4/5 or 3/4 salary is reasonably simple (I eve

Talk to your accountant. I would say, that for people wanting i.e. 3 day weekend, or 6 hour days, agreeing on the 4/5 or 3/4 salary is reasonably simple (I even managed to use this in my salary negotiation, where they offered me X$ for full time, and I managed to negotiate 85% X for 4/5 part-time) The extra day/two hours are not as big of a difference in productivity anyway :) I would say there is bigger difference in below 3/5 part-time, and in companies I have been at, there is assumption that people with less than 3/5 part-times are sort-of on extended trainig? I.e. summer project -> internship -> part-time -> full time progression was expected over ~2 years. If you can, and your regulatory environment allows it, look for other means of employment. You could help your new highers become self-employed and then have just an agreement for billable-hours, but you can easily break the regulations for social security payments this way. In my country we have 'agreement about commisioned work', that is somewhere in the middle between being fully employed, and being self employed, but with some aditional constraints on maximum billable-hours per month? I don't remember, do consult your accountant responsible for payroll :-)