Enter Last menstrual period (LMP), Cycle length (days) and Method to review due date with this tool. Calendar milestones are calculated from an assumed dating basis.
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), Cycle length (days) and Method to due date. Calendar milestones are calculated from an assumed dating basis. They do not establish fetal development or the exact timing of delivery.
Enter Last menstrual period (LMP), Cycle length (days) and Method to review due date with this tool. Calendar milestones are calculated from an assumed dating basis.
Explore pregnancy calendar milestones from the selected reference date. Keep the estimated due date, elapsed gestational time and milestone labels distinct.
Calendar milestones are calculated from an assumed dating basis. They do not establish fetal development or the exact timing of delivery.
Prepare Last menstrual period (LMP), Cycle length (days) and Method. Select the date basis that matches the information available and check the current-date assumption used for elapsed weeks.
Calendar milestones are calculated from an assumed dating basis. They do not establish fetal development or the exact timing of delivery. Uncertain last-period dates, irregular cycles and clinical findings can change pregnancy dating. A clinician’s established due date may take precedence.
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. Select the date basis that matches the information available and check the current-date assumption used for elapsed weeks.
Uncertain last-period dates, irregular cycles and clinical findings can change pregnancy dating. A clinician’s established due date may take precedence. For personal care, discuss the measurements and method with a qualified clinician.
Worked pregnancy calculator example. Set Last menstrual period (LMP) = 2026-01-01; Cycle length (days) = 28; Method = Naegele's Rule (LMP). The corresponding output is Due Date: October 8, 2026. Calendar milestones are calculated from an assumed dating basis.
Explore pregnancy calendar milestones from the selected reference date. Keep the estimated due date, elapsed gestational time and milestone labels distinct.
Select the date basis that matches the information available and check the current-date assumption used for elapsed weeks.
| Field | Example value | Entry check |
|---|---|---|
| Last menstrual period (LMP) | 2026-01-01 | Use the calendar date for this scenario; keep the comparison date explicit. |
| Cycle length (days) | 28 | Use the stated unit and the measurement required by this model. |
| 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.
Calendar milestones are calculated from an assumed dating basis. They do not establish fetal development or the exact timing of delivery.
| 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.
Calendar milestones are calculated from an assumed dating basis. They do not establish fetal development or the exact timing of delivery. Uncertain last-period dates, irregular cycles and clinical findings can change pregnancy dating. A clinician’s established due date may take precedence.
Replace the illustrative last menstrual period (lmp) value (2026-01-01) with your own value, then complete the other inputs for the same scenario. Select the date basis that matches the information available and check the current-date assumption used for elapsed weeks.