Calculating Basic from CTC
First, to calculate Basic from CTC. For example, if your CTC is 55900/-, calculate your Basic as 30% to 50% from CTC (55900/- * 39.36% = 22002/-). 22002/- is your basic amount.
Calculating HRA and Other Allowances
Now, calculate your HRA as Basic * 50% (22002/- * 50% = 11001/-), then Conveyance Allowance (1600/-), Medical Allowance (1250/-), Other/Special Allowances (13530/-), etc.
Basic = 22002/-
HRA = 11001/-
Conveyance Allowance = 1600/-
Medical Allowance = 1250/-
Other Allowance = 13530/-
Total Gross = 49383/-
ESI Contributions
Employee contribution to ESI: Gross * 1.75%
Employer contribution to ESI: Gross * 4.75%
Total = 6.50%
As per my knowledge, please calculate your gross from CTC.