https://www.nhs.uk/live-well/healthy-weight/bmi-calculator/

Once upon a time the NHS encouraged websites to 'embed' their calculator in their own web pages. Now they do not. I consider it better to visit the NHS anyway and use their very simple script which has been refined over time, as is now more inclusive with regard to ethnic influences and other matters.

It is not proposed to discuss BMI. That is a separate subject and not relevant here. Once you have your instant results you could check the rest of that page for useful information, some of which may be relevant to you personally.

What it did for me and will do for you, is provide minimum and maximum guideline kcal figures, which are absolutely essential as a first step on which to base your plan. You will quickly be able to judge progress and be able to make adjustments if necessary, as required. You absolutely must have a base line to work to. The spreadsheet needs those two numbers.

Like this website, the NHS utility does not require any personal identifying information or registration. Quick and simple but amazingly useful.