Not sure if there is an official answer but I would say that if it bothers you then it is too much. If it causes you undue pain, anguish or embarrassment then it is too much.

How to put pay to it? 

Well,  there is no one-fits-all solution. 

You can take probiotics that can be effective at controlling it. Reduce dairy products that are major gas producers, avoid starchy carbs and sugar in the same meal (avoid fruits after meals?) and do not drink juice with meals. 

I am a firm believer that separating your food groups helps (that is a personal opinion, not a fact) so I do...it has helped me with digestion and lowered my gas level but it is not an obligation.

Avoid sodas and sugary foods.

Sharon

Some folks have had success from paying careful attention to how they chew and swallow, to avoid swallowing air. In other cases extreme gas can be from bacterial overgrowth. If that turns out to be your situation the standard treatment is a few months of an antibiotic like doxycycline. 

Look at doing a FODMAPs elimination or SCD diet, followed closely with your GI. No beans/legumes or gluten for me ever. But found I have trouble will all grains, dairy and polyols...so I limit those. Just some thoughts.