Motor and developmental assessments are normed by exact age — and for the infants you see, prematurity matters too. This free calculator gives the precise years;months;days in the borrow-30 format your manuals expect.
Why exact age matters for motor assessment
Developmental motor scales sort children into narrow age bands. An age that's off by days can shift the standard score and the eligibility call. The publisher convention is borrow-30 (every month = 30 days), which a general calendar calculator does not produce.
Instruments this matters for
- PDMS-2 — Peabody Developmental Motor Scales
- Bayley-4 — Bayley Scales of Infant & Toddler Development
- AIMS — Alberta Infant Motor Scale
- Sensory Profile 2 and other age-banded tools
NICU follow-up & prematurity: for infants born preterm, developmental scoring should use corrected age (chronological age minus weeks born early) until about 24 months, per the American Academy of Pediatrics. Using chronological age instead can swing an infant's Bayley score by double digits.
What this tool gives you
- Exact years;months;days in borrow-30 format
- Works offline — no signal needed in the clinic or on home visits
- Deterministic, unit-tested math; 100% private — nothing you enter leaves your device
Why not just use a generic calculator? It uses calendar math, not the borrow-30 result — here's why that matters →
Built for your assessments
- Speech-Language Pathologists
- School Psychologists
- Pediatric OTs & PTs
- Early Intervention
Exact chronological age in seconds — free.
Free iOS / Mac app, or use it in your browser. No ads, no accounts, no subscription.
