Help with alpha acid conversion

[Newbibrewbi]

I’ve got a recipe where the hops are written out as grams alpha acid per hl and I need to convert it to IBUs for beersmith.
Does anyone have a formula for this?

Recipe says:
Boil 70 mins
Hercules 7,5g aa /hl at boil start
Saaz 0,8 g after 60 mins.

I interpret this as 0,8 g aa/hl for the saaz as well but how much should I put?

Any ideas on how this math maths is welcome.

 

[marc1]

I'd get the AA content by taking the AA percentage of the hops and multiplying it by the weight.

So if the Hercules was 10%AA, 100g would be 10g of AA.

Use the actual AA of your hops and figure out how much to use in a hl. Then scale from 1hl to your batch size.