Any "active insulin" calculators?

Been looking for an active insulin calculator/remaining on Google and various App Stores, nothing.

 

Looking for a tool to estimate the remaining active insulin so I can properly calculate correction doses/bolus doses.

 

MySugr seems to offer experimental active insulin tool but only for EU (and pro version) and I'm in Canada.

 

Anyone knows of such a tool or even the algorithm

 

My old pump (now using pens) had such a tool and it was great to calculate actual boluses