Enquiry about exemption of allowances from income tax

no need to calculate. your employer based on the information provided by you, will consider it in your form 16. if any other information, which is not a part of form 16, then you have to claim outside.

it is better to provide all information to employer to include all income and specifically deduction. if you claim anything outside the form 16, then dept may call the documents for the deduction claim outside form 16.

simply file ITR using form 16 details..