How to calculate the accumulated leave?

Hi Madam,

I have read in one of your answers to a question regarding the calculation of leave salary at the end of job, termination, or resignation, that the leave salary for accumulated leaves will be calculated based on Basic Wage.

My doubt is what is accumulated leave?

If I received all the dues of leave salary on last leave and I resigned 1 year after resumed duty, only 1 month leave salary is due for me. Is it consider accumulated leave or is it a normal annual leave?

And, why the calculation is based on basic pay in this case?

I think the accumulated leaves are the days due more than 60 days. Please advise me as I am planning to resign from my job.

I completed 20 years in the same company and there is no unpaid leave salary except the last 1 year of service.