Well - I ask how well do you wish it to actually calculate your bolus/correction dose - to do it accurately it needs access to your insulin on board info which the pump knows, but nobody else does instantly, so whether it's a meter or a phone app, it needs sufficient info entered into it, in order to enable it to access that info and make an accurate calculation.
Otherwise you could just calculate the required dose for Xgrams of carb using mental arithmetic or a calculator which is on most phones anyway if you can't do mental arithmetic.
I recall a consultant saying to me when my afternoon ratio was 1u to 8g carb, ooh that makes it difficult for you! No it doesn't said I - I learned my 8 times table when I was little! However - I am now fully aware that junior schools don't teach you the times tables these days. Grand daughter aged 8 - after I had a rant that they weren't taught them now - later told Grandad that Grandma clearly has an anger management issue about it. I don't believe that phrase had even been invented when I was her age in the 1950s ! Hence I can't complain if anyone younger than me can't multiple or divide in their heads - but still think that's utterly ridiculous.