Compare calculators
Both calculators run independently β change the inputs on either side to compare results.
Due Date Calculator (Naegele's Rule)
Estimate your due date from your last menstrual period using Naegele's rule, adjusted for your actual cycle length and luteal phase so a non-28-day cycle isn't misdated.
Days until estimated due date
224 days
More than 189 days until your due date puts you in the first trimester (under ~13 weeks), the window covering the dating ultrasound and initial prenatal visit.
Counts calendar days until your estimated due date using Naegele's rule (266 days from conception), so each band corresponds to a pregnancy trimester window.
Gestational Age Calculator
Converts the number of days since your last menstrual period into gestational age expressed as weeks and days. Use it at any point in pregnancy to know your exact stage for prenatal care, screenings, and milestone tracking.
Key differences
| Due Date Calculator (Naegele's Rule) | Gestational Age Calculator | |
|---|---|---|
| Category | Pregnancy | Pregnancy |
| Inputs required | 3 | 1 |
| Result | Days until estimated due date (days) | Gestational age (weeks) |
| What it does | Estimate your due date from your last menstrual period using Naegele's rule, adjusted for your actual cycle length and luteal phase so a non-28-day cycle isn't misdated. | Converts the number of days since your last menstrual period into gestational age expressed as weeks and days. Use it at any point in pregnancy to know your exact stage for prenatal care, screenings, and milestone tracking. |