If we are going to post/list our favorite calculator apps, I like these.
None of mine are free, though.
Digits https://apps.apple.com/us/app/maxicalc-pro-big-retro-lcd-paper-tape-calculator/id622309324
I have had Digits Calculator on my iPads since the first 2010 iPad and iOS 5.1.1.
Love Digits calculator.
Calc Pro HD – iPad Calculator by Panoramic Software Inc.
https://apps.apple.com/us/app/maxicalc-free-big-retro-lcd-basic-desk-c
This one covers a lot of conversion stuff, as well as standard calculator functions.
I get a lot of use out of this one, too.
I tend to like calculator apps that use the calculator tape roll analogy.
AND, just to have and use for both fun and nostalgia and to get a rise out of friends and family.
MaxiCalc Free: Big Retro LCD Basic Desk Calculator by Fernando Sciessere
https://apps.apple.com/us/app/maxicalc-free-big-retro-lcd-basic-desk-calculator/id657247248
OR
MaxiCalc Pro: Big Retro LCD Paper Tape Calculator by Fernando Sciessere
https://apps.apple.com/us/app/maxicalc-pro-big-retro-lcd-paper-tape-calculator/id622309324
This is a very good modern re-creation of the old-school loudest and noisy-est electric tape roll adding machines from the 1970’s, with all of the modern calculator functions built into this calculator app!
Chunky, clack-y huge number push buttons, and all!
I JUST LOVE IT! And it looks great on my 12.9 inch iPad Pro!
To the Original Poster,
There are a WHOLE LOTTA third party calculator apps designed for iPad.
Lots of great-looking calculator apps for iPad.
Some even mimic classic pocket calculators from the 1960’s, ‘70’s, ‘80’s and ‘90’s!.
Have fun finding a calculator app you like!