Enter Last menstrual period (LMP) and Calculation method to review due date with this tool. An estimated delivery date marks the model’s end of the gestational interval.
The date estimate is calculated from the entered cycle, last menstrual period, conception date or gestational reference using standard calendar intervals.The calculation links Last menstrual period (LMP) and Calculation method to due date. An estimated delivery date marks the model’s end of the gestational interval. It is a reference for discussion, not a guaranteed birthday.
Enter Last menstrual period (LMP) and Calculation method to review due date with this tool. An estimated delivery date marks the model’s end of the gestational interval.
Compare a due-date estimate from the pregnancy dating method selected in the form. This page focuses on translating the chosen reference into an expected date.
An estimated delivery date marks the model’s end of the gestational interval. It is a reference for discussion, not a guaranteed birthday.
Prepare Last menstrual period (LMP) and Calculation method. Keep last-period, conception and clinician-provided dates in their own fields; do not interchange them.
An estimated delivery date marks the model’s end of the gestational interval. It is a reference for discussion, not a guaranteed birthday. Clinical dating, ultrasound findings and cycle variation cannot be resolved by a calendar formula alone.
Use the full settings in the worked-example table. They produce Due Date: October 8, 2026. Compare the method and units as well as the displayed number.
The displayed relationship is The date estimate is calculated from the entered cycle, last menstrual period, conception date or gestational reference using standard calendar intervals. Keep last-period, conception and clinician-provided dates in their own fields; do not interchange them.
Clinical dating, ultrasound findings and cycle variation cannot be resolved by a calendar formula alone. For personal care, discuss the measurements and method with a qualified clinician.
Worked pregnancy due date calculator example. Set Last menstrual period (LMP) = 2026-01-01; Calculation method = Naegele's Rule (LMP). The corresponding output is Due Date: October 8, 2026. An estimated delivery date marks the model’s end of the gestational interval.
Compare a due-date estimate from the pregnancy dating method selected in the form. This page focuses on translating the chosen reference into an expected date.
Keep last-period, conception and clinician-provided dates in their own fields; do not interchange them.
| Field | Example value | Entry check |
|---|---|---|
| Last menstrual period (LMP) | 2026-01-01 | Use the calendar date for this scenario; keep the comparison date explicit. |
| Calculation method | Naegele's Rule (LMP) | Select the method before interpreting the result; different modes answer different questions. |
Relationship used for this example: The date estimate is calculated from the entered cycle, last menstrual period, conception date or gestational reference using standard calendar intervals.
An estimated delivery date marks the model’s end of the gestational interval. It is a reference for discussion, not a guaranteed birthday.
| Output | Displayed result |
|---|---|
| Due Date | October 8, 2026 |
With these settings, due date is October 8, 2026. Use the same units and calculation mode when reproducing this example.
An estimated delivery date marks the model’s end of the gestational interval. It is a reference for discussion, not a guaranteed birthday. Clinical dating, ultrasound findings and cycle variation cannot be resolved by a calendar formula alone.
Replace the illustrative last menstrual period (lmp) value (2026-01-01) with your own value, then complete the other inputs for the same scenario. Keep last-period, conception and clinician-provided dates in their own fields; do not interchange them.