Absolute Humidity: Function or Lookup

Hey all,
I want to calculate the absolute humidity for all my temp/hum sensors so that I can compare them better against each other and decide if it’s a good idea to open a window.
I alread found threads that describe how to do it with a function to calculate the value. But in my case that would be 6 sensors doing this calc every time a value changes or even more often on a fixed schedule?
I think the formula is not that trivial and as I’m running on a PI4 I thought about alternative ideas to tackle the issue in the most efficient way. So if storage or memory won’t be an issue I could save processing power by using some sort of lookup table.
So if we talk about -30.0 to +50.0 °C and 0.0% to 100.0% we will end up with 800000 keys.
Is that something thats worth a thought or am I running into a wrong direction here?
If thats a reasonable idea, does anybody have an idea how to approach that?
Thanks in advance

Can you provide a link to the threads that you found? Doing thousands of calculations in a RPI 4 is no problem. The table idea sounds like a bit much.

There’s a nice custom_component in HACS.