Date & Time
The exact age at testing — in years, months, and days — the way schools, speech-language pathologists, psychologists, and clinics calculate it.
Calendar method: subtract the birth date from the test date column by column — days, then months, then years. If the day subtraction goes negative, borrow the number of days in the month before the test date (e.g., testing on March 10 borrows 28 or 29 days from February); if the month subtraction goes negative, borrow 12 months from the year. This is the hand-calculation method taught for standardized test protocols, and it is exact.
30-day-month method: some test publishers and clinical tools simplify every month to 30 days and every year to 360 days. Take the total number of days between the two dates, then divide: years = total days ÷ 360, months = the remainder ÷ 30, days = what's left. The two methods can differ by a few days — use whichever method your test manual or protocol specifies. Age equivalents and eligibility cutoffs (for example, school-entry or early-intervention ages) are usually based on the calendar method.
This tool is for quick reference. Always confirm critical eligibility or diagnostic calculations against the specific test publisher's instructions.
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