Need formula for accrued vacation time for Excel 2013

I need to create a spreadsheet to track accrued vacation time earned and used. I am new to Excel, can anyone help me with a formula? PLEASE??? Vacation is earned at a rate of .625 days per pay period, which is twice a month.

This is a little bit vague. I think what you are asking for quite possible, but the format for the sheet is important to how the formula is written. Can you make a sample layout and give some directions as to how you want it to work. I will happy to help with the formula and will even fill in some of the sheet for you if you would like!

Hi!'
I'm jumping in here with my specific situation.

I'm looking to create a spreadsheet that tracks each employee's vacation, including monthly accrual in real time, plus carryover dates from previous years, days used and balance available. Each employee starts accruing as of their 90th day, at a rate of 3.33 hours/month for the first year. THEN, after hitting the 1st year anniversary, the accrual changes to 4 hours/month (yielding 6 days available for that year). The pattern continues each year, adding one more day (i.e. changing the accrual rate on each anniversary). I would love for the spreadsheet to automatically update the accrual rate on each employee's anniversary but haven't been able to figure it out. Would love to hear any suggestions!
Thanks!