I am SO confused and would really appreciate some help. How do I work out what my take home will be after tax and national insurance from my SMP payments? I have made a massive underestimation in my savings account as totally forgot to account for tax and national insurance (I could cry, well actually, I am!). My maternity leave has already started, and I'm 9 days postpartum so maybe totally over emotional anyway. Have attached a picture of my monthly SMP payments before any deductions. My tax code is 1263L. I am in a commission paid job so my monthly payments are never the same (if that makes a difference).