I am part of a small company who uses SharePoint. The administrators can't see my calendar and mine is the only one, and I can't find where to change my permissions so that they can. Please advise.
Is the calendar you're referring to a SharePoint calendar or an Exchange/Outlook calendar?
If it's a SharePoint Calendar you can go the the page you'd like everyone to access the calendar from then settings>add an app> Calendar> then on the left side 'Calendars in View'> New Calendar> then provide the URL and name of the calendar you want everyone to be able to see.
If it's from Outlook/Exchange, do the same steps as above however click the 'Exchange' radio button instead of SharePoint after clicking 'New Calendar'. Click the 'Find' button to auto populate your EWS and OWA URLs. if that doesn't work more information on how to find them is here. Then click 'okay.
Everyone will be able to see that calendar overlay as long as they have access to that public calendar.