Chronological Age Calculation Examples for WISC-V, WAIS-IV & KTEA

July 14, 2026

Seeing the calendar-subtraction method applied to real dates makes the rounding rule click faster than a formula alone. Below are five worked examples, each showing the exact age, the borrowing step where it applies, and the final rounded test age used for WISC-V, WAIS-IV, and KTEA-3 norm lookup. Verify your own dates against the chronological age calculator — every example below was checked against the same calendar-subtraction method it uses.

For the full rule behind the rounding step shown here, see WISC-V, WAIS-IV & KTEA age-band rounding rules explained.

Example 1 — A Straightforward Case (No Borrowing Needed)

Birth date: November 8, 2016 · Test date: July 14, 2026

years  = 2026 − 2016 = 10
months = 7 − 11 = −4  →  borrow: +12 months, −1 year
days   = 14 − 8 = 6   →  no borrow needed (test day ≥ birth day)

Exact age = 9 years, 8 months, 6 days
Remainder = 6 days → 15 or fewer → round down

Test age: 9:8 (reported as “9 years, 8 months”)

Example 2 — Borrowing Across a Short Month

Birth date: January 30, 2019 · Test date: March 20, 2026

years  = 2026 − 2019 = 7
months = 3 − 1 = 2
days   = 20 − 30 = −10  →  borrow from February 2026 (28 days): −10 + 28 = 18
months = 2 − 1 = 1

Exact age = 7 years, 1 month, 18 days
Remainder = 18 days → 16 or more → round up

Test age: 7:2

Notice the exact age (7 years, 1 month) and the rounded test age (7:2) are a full month apart. Reporting the un-rounded figure here would place this examinee in the wrong norm-table row.

Example 3 — A Leap-Day Birthday

Birth date: February 29, 2020 (leap year) · Test date: March 1, 2026

years  = 2026 − 2020 = 6
months = 3 − 2 = 1
days   = 1 − 29 = −28  →  borrow from February 2026 (28 days, non-leap): −28 + 28 = 0
months = 1 − 1 = 0

Exact age = 6 years, 0 months, 0 days
Remainder = 0 days → round down

Test age: 6:0

Because 2026 is not a leap year, February has only 28 days to borrow from, so this examinee’s calendar age lands exactly on 6 years, 0 months on March 1 rather than February 29. This is the kind of edge case that trips up spreadsheet formulas that assume every February has 29 days — see common mistakes when calculating test age for more on this.

Example 4 — Just Above the Rounding Threshold

Birth date: June 15, 2021 · Test date: July 1, 2026

years  = 2026 − 2021 = 5
months = 7 − 6 = 1
days   = 1 − 15 = −14  →  borrow from June 2026 (30 days): −14 + 30 = 16
months = 1 − 1 = 0

Exact age = 5 years, 0 months, 16 days
Remainder = 16 days → 16 or more → round up

Test age: 5:1

Example 5 — Just Below the Rounding Threshold (One Day Earlier Birth Date)

Birth date: June 16, 2021 (one day later than Example 4) · Test date: July 1, 2026

years  = 2026 − 2021 = 5
months = 7 − 6 = 1
days   = 1 − 16 = −15  →  borrow from June 2026 (30 days): −15 + 30 = 15
months = 1 − 1 = 0

Exact age = 5 years, 0 months, 15 days
Remainder = 15 days → 15 or fewer → round down

Test age: 5:0

Examples 4 and 5 use birth dates exactly one day apart, yet the reported test age differs by a full month — 5:1 versus 5:0. This is the clearest possible demonstration of why the exact birth date, computed to the day, has to feed the rounding rule rather than an approximate or remembered date. A single transposed digit in a birth date can produce exactly this kind of one-month swing in a final report.

Try Your Own Dates

Every example above follows the same two-step process: exact calendar subtraction with borrowing, then the 15/16-day rounding threshold. Enter any birth date and test date into the chronological age calculator to get both the exact age and the rounded WISC-V/WAIS-IV/KTEA-3 test age instantly, without doing the borrowing arithmetic by hand.