Age as Calculator

YYYY-MM-DD. Required in every mode except the reverse mode, which works it out for you.
Leave blank to use today. Set it to any past or future date to age forward or backward.
Supply a second birth date to get the age gap between two people.
Reverse mode: the age the person was (or will be) on the date above.
Reverse mode: optional. Given, it pins the birth date to a single day.
Reverse mode: optional.
ASQ mode: completed weeks of gestation at birth. 40 weeks is full term.
ASQ mode: the days part of the gestational age, e.g. 32 weeks 4 days.
ASQ mode: if you know the due date, it is used instead of the gestational age.
Age in years
20 years
Age Calculator
Extra months
0 months
Extra days
0 days
Age
20 years, 0 months, 0 days
Chronological age (years;months)
20;0
Age in decimal years
20.0004 years
Age in months
240 months
Age in weeks
1,043 weeks
Days lived
7,305 days
Hours lived
175,320 h
Minutes lived
10,519,200 min
Seconds lived
631,152,000 s
Whole weeks after the months
0 weeks
Days after those weeks
0 days
Age in years, months, weeks and days
20 years, 0 months, 0 weeks, 0 days
Born on a
Saturday
Next birthday
2021-01-01
Next birthday falls on
Friday
Days until the next birthday
366 days
Age on the next birthday
21 years
Worked out from ISO 8601-1:2019, Date and time - Representations for information interchange and 4 other sources.

How this is worked out

5 steps
  1. Born 2000-01-01 (a Saturday); measuring on 2020-01-01.
  2. Whole years first: 2000-01-01 + 20 years lands on or before 2020-01-01.
  3. Then whole months and days: + 0 month(s) + 0 day(s) reaches 2020-01-01.
  4. Elapsed days = 7,305, i.e. 1043 weeks and 4 day(s).
  5. Next birthday 2021-01-01 (Friday), 366 day(s) away; turning 21.
The same age in every unittable
Years: 20, Months: 240, Weeks: 1,043, Days: 7,305, Hours: 175,320, Minutes: 10,519,200, Seconds: 631,152,000

Results are general information, not financial, tax, legal, medical or engineering advice.