Corrected Age and Gestational-Week Equivalent
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Valid entry range: 1900–2100. Enter the evaluation date manually.
Gestational age at birth is not derived; without a birth date the tool cannot determine preterm status or whether the evaluation follows birth.
Corrected calendar age （Estimated due date (EDD))
—Enter both dates.
Gestational-week equivalent (EDD = 40 weeks 0 days)
—EDD is assumed equivalent to 40w0d.
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Calendar method and clinical limitations
Method
EDD corresponds to a gestational-week equivalent of 40w0d (280 days). Calculate signed calendar days from EDD to evaluation and add to 280, then divide by seven. This is NOT the gestational age at birth.
Corrected calendar age counts completed calendar months since EDD, plus residual days. Month-end dates are clamped to the final day where necessary. Before EDD, negative weeks and days are shown instead of completed age months. The week-equivalent display is limited to 0w0d–44w6d for UI purposes, not medical criteria.
Hypothetical example
EDD 2026-05-01, assessment 2026-04-10: 21 days before EDD, or minus 3 weeks 0 days, gestational-week equivalent 37w0d. On 2026-06-01: 1 month 0 days since EDD, equivalent 44w3d.
Population and limits
Without an actual birth date, this tool cannot determine the gestational age at birth, whether the child has been born, chronological age or preterm birth status. Relevance of corrected age to developmental assessment varies with the individual and purpose. The 36-month warning is a review prompt, not a clinical decision rule.
Sources and review
Sources checked 2026-11-10.