Age difference calculator
The age difference between two people is the gap between their birth dates, and it never changes. Someone born in 1990 and someone born in 1994 are always four years apart, whatever ages they happen to be.
How to find an age difference
The constancy is what people get wrong. A four-year gap feels enormous between a six-year-old and a two-year-old and negligible between a fifty-year-old and a forty-six-year-old, but the gap itself has not moved. What changes is the ratio: four years is twice the whole life of the younger child in the first case and under a tenth in the second, which is why the same gap reads so differently at different stages.
Questions
No. The gap between two birth dates is fixed; what changes is how large it feels relative to their ages.
Take the difference between the two birth dates in years, months and days.
No; the gap is the same either way.
Because the ratio to the younger person age shrinks as both get older.
Yes, it is just a date difference under a different name.