Everyone is different.
It’s one of humanity’s strengths – we’re diverse in more ways than one!
Bearing that in mind when it comes to the ideal weight then it’s obviously not as simple as some might think.
If you are a broad shouldered giant you will be able to carry a lot more weight than a lanky beanpole!
The simplest method for calculating ideal weight is via their BMI (body mass index) which basically takes into account height, gender and weight to come up with a figure. Based on that figure you can then see if someone is overweight etc., etc.
If you want to work out your BMI then there are plenty of tools online to help you.
Here are a couple I found (I’m not saying they’re better or worse than any others!)
You’ll obviously need to know your height AND weight to be able to use any of those tools!