Compare calculators
Both calculators run independently β change the inputs on either side to compare results.
Ovulation & Fertile Window Calculator
Pinpoint your likely ovulation day and fertile window from your cycle length, luteal phase, and the cycle day you're on today β based on the fixed-luteal-phase method.
Days until ovulation
8 days
More than 6 days until ovulation means you are before the fertile window. Conception is unlikely now; the window opens about 5 days before your predicted ovulation.
Counts days until ovulation as (cycle length minus luteal phase) minus current cycle day; the fertile window spans the 5 days before ovulation through ovulation day itself.
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
| Ovulation & Fertile Window Calculator | Gestational Age Calculator | |
|---|---|---|
| Category | Pregnancy | Pregnancy |
| Inputs required | 3 | 1 |
| Result | Days until ovulation (days) | Gestational age (weeks) |
| What it does | Pinpoint your likely ovulation day and fertile window from your cycle length, luteal phase, and the cycle day you're on today β based on the fixed-luteal-phase method. | 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. |