DueNest makes free, accurate and private calculators for pregnancy, fertility and baby care, with clear explanations and cited sources.
Last updated: October 2, 2026
Expecting and new parents look up the same questions again and again: when is my baby due, how many weeks am I, is my baby growing well. Many tools online give an answer without explaining it. We wanted calculators that show the method, cite their sources and work well on a phone.
Every calculator uses the same methods that doctors use, such as Naegele's rule for due dates and the WHO Child Growth Standards for baby growth. Each page explains the formula and lists its sources. All calculations run in your browser, so the dates and measurements you enter are not sent to us.
We are not doctors. Every formula comes from published guidance by ACOG, WHO, the NHS or the CDC, and we test each calculator against worked examples before it is published. See how we calculate. Read more about how we write and check content in our editorial policy.
DueNest is run by [OWNER OR COMPANY NAME], based in [COUNTRY]. You can reach us through our contact page.
Our calculators give estimates for information only. They do not replace advice from your doctor or midwife. If you are worried about your health or your baby's health, please contact a medical professional.
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