I am building a chicken coop as a project at a local school and I am needing to know to calculate the require amount of cement, gravel and sand mix and how to calculate the amount of concrete for the job.
Sounds like a great little community project @Rob2. I'm sure community members will be happy to help with your calculations.
Do you also need some inspiration for the chicken coop? Here's some posts that might help on that front:
Welcome to the Workshop community. We're pleased to have you join us and look forward to seeing how this project progresses. Feel free to post whenever you need a hand with anything.
Could you please clarify what you are building? Is it just a standard concrete slab to build the coop on? Proportions of cement/gravel/sand depend on the strength you need...
Something like these concrete calculators should do the job: