Practice · 8 problems with answers
Chronological Age Examples & Practice Problems
Work through eight chronological age examples, from easy to tricky, and check your answers instantly. Each one shows the full working, including borrowing months, years and leap days.
By Sandeep · Updated November 2026
Before you start, you may want to review how to calculate chronological age. Then try each problem: subtract the birth date from the test date, type your answer and press Check.
Practice problems
Score: {{score}} / 8Born 5 March 2019, tested 17 August 2026. What is the chronological age?
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Answer: 7;5;12. No borrowing: 2026 − 2019 = 7, 8 − 3 = 5, 17 − 5 = 12.
Born 10 June 2020, tested 28 November 2026. What is the chronological age?
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Answer: 6;5;18. No borrowing: 6 years, 11 − 6 = 5 months, 28 − 10 = 18 days.
Born 25 September 2018, tested 10 April 2026. What is the chronological age?
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Answer: 7;6;16. Borrow March (31 days): 10 + 31 = 41, month 3. Borrow a year: 3 + 12 = 15, year 2025. Then 7, 15 − 9 = 6, 41 − 25 = 16.
Born 30 January 2017, tested 2 March 2026. What is the chronological age?
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Answer: 9;1;0. Borrow February 2026 (28 days): 2 + 28 = 30, month 2. Then 9 years, 2 − 1 = 1 month, 30 − 30 = 0 days.
Born 15 December 2021, tested 7 January 2026. What is the chronological age?
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Answer: 4;0;23. Borrow December (31 days): 7 + 31 = 38, month 0. Borrow a year: 12 months, year 2025. Then 4, 12 − 12 = 0, 38 − 15 = 23.
Born 30 November 2019, tested 29 November 2026. What is the chronological age?
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Answer: 6;11;30. Borrow October (31 days): 29 + 31 = 60, month 10. Borrow a year: 22 months, year 2025. Then 6, 22 − 11 = 11, 60 − 30 = 30. One day short of 7!
Born 29 February 2020 (leap day), tested 1 March 2024. What is the chronological age?
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Answer: 4;0;1. 2024 is a leap year, so borrow February (29 days): 1 + 29 = 30, month 2. Then 4, 2 − 2 = 0, 30 − 29 = 1.
Born 4 July 2015, tested 4 July 2026. What is the chronological age?
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Answer: 11;0;0. Same day and month, so exactly 11 years, 0 months, 0 days.
Types of Chronological Age Examples
Every chronological age example falls into one of four types. Once you can spot the type, the working becomes routine:
- No borrowing: every part of the test date is larger than the birth date, as in problems 1 and 2. Just subtract.
- Borrow a month: the test day is smaller than the birth day. Take one month and add its days, as in problem 4.
- Borrow a month and a year: after borrowing a month, the months are still too small, so borrow 12 months from the year, as in problems 3, 5 and 6.
- Leap years and exact birthdays: February has 29 days in a leap year (problem 7), and a test on the birthday gives 0 months and 0 days (problem 8).
Tips for Getting Every Example Right
- Borrow from the month before the test month. For a test in April, use March’s 31 days.
- Write the dates in columns first. Year, month, day, with the test date on top.
- Check leap years. 2024, 2028 and 2032 have a 29 February.
- Sanity check the answer. If the birthday has already passed this year, the years should equal the difference in years; if not, one less.
- Check with a calculator. Our chronological age calculator shows the same working, so you can compare step by step.
Chronological Age Examples in Real Life
Chronological age examples are not just classroom exercises. Speech-language pathologists, school psychologists and teachers calculate an exact age for every standardized test, and parents check it for school entry and premature babies. A one-day error can change a norm table, which is why practice matters. See our chronological age for testing guide, the corrected age calculator for babies born early, and school age calculator for kindergarten start dates.
Printable Practice
Teachers and trainers can print this page for a quick worksheet: the problems print without the answers, which only appear when you press Show answer on screen. For more background, read what is chronological age.
Chronological Age Examples FAQs
What is an example of chronological age?
A child born on 25 September 2018 is 7 years, 6 months and 16 days old on 10 April 2026, written 7;6;16.
How do you practice calculating chronological age?
Work through examples of increasing difficulty, starting with no borrowing, then borrowing a month, then a month and a year, and finally leap years. The practice problems above follow that order.
What is the hardest type of chronological age problem?
Problems that need borrowing both a month and a year, especially when the borrowed month is February in a leap year.
Can I print these chronological age practice problems?
Yes. Use your browser’s print option. Answers stay hidden unless you reveal them on screen first.