[bitwize]

Handheld calculators typically get between 8 and 12 digits of precision. A four-function calculator will top out at 8; a scientific calculator will offer more (plus scientific notation support).

15 digits is about what's offered in double precision floating point calculations.

[progers7]

If you're interested in common handheld calculators, you might enjoy this light-hearted series by Matt Parker titled "Calculator Unboxing": https://www.youtube.com/watch?v=8Nzi1h2m7pE&list=PLt5AfwLFPx...