Ovulation Calculator — Best Days to Get Pregnant
To maximise your chance of conceiving, time intercourse to the fertile window — the five days before ovulation and ovulation day itself. Because sperm survive up to five days, starting a few days before ovulation works as well as the day itself. Enter your last period and cycle length to see your most fertile days for the next six cycles, plus the earliest reliable date to take a pregnancy test.
Enter your last period date and press Calculate to see your fertility predictions.
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Frequently asked questions
What are the best days to get pregnant?+
The two to three days before ovulation and ovulation day itself are the most fertile. Having intercourse every 1–2 days through your fertile window gives the best chance of conception without needing to pinpoint the exact ovulation day.
How soon after the fertile window can I test for pregnancy?+
Wait until about 14 days after ovulation — usually the day your next period is due — for the most reliable home pregnancy test result. Testing earlier can give a false negative because hCG levels are still low. The calculator shows the earliest sensible test date for each cycle.
How long does it usually take to conceive?+
Most healthy couples conceive within a year of trying. Around 8 in 10 conceive within 12 months of regular, well-timed intercourse. If you're under 35 and it's been over a year — or over 35 and it's been six months — see a fertility specialist.
How does the ovulation calculator work?+
It uses the calendar method: in a typical 28-day cycle, ovulation happens around day 14 (counting day 1 as the first day of your last period). The fertile window is the 5 days leading up to ovulation plus the day of ovulation itself — sperm can survive for 3–5 days, so intercourse during this window has the highest chance of conception. Enter your last period date and average cycle length, and the calculator computes your fertile window, ovulation day, and implantation date for the next 6 cycles.
When am I most fertile?+
Your most fertile days are typically the 3 days before ovulation plus ovulation day itself. For a regular 28-day cycle, that's roughly days 11–15 (counting day 1 as your first day of menstruation). For longer or shorter cycles, the fertile window shifts proportionally — this calculator does the math for your specific cycle length.
What is the implantation date the calculator shows?+
Implantation happens 6–12 days after ovulation, when a fertilised egg attaches to the uterine lining. The calculator estimates this window — useful if you're tracking for early pregnancy testing or noticing implantation symptoms (light spotting, mild cramping).
When can I take a pregnancy test?+
Home pregnancy tests detect the hCG hormone produced after implantation. Most tests are accurate from 7–10 days after ovulation, with the most reliable results 14 days after ovulation (around the time your next period would start). The calculator shows the earliest test date for each cycle so you don't test too soon.
Is this calculator a substitute for medical advice?+
No. It's an educational tool based on calendar averages. If you've been trying to conceive for over a year (or 6 months if you're over 35), or have known fertility concerns like PCOS, consult a gynaecologist or fertility specialist for personalised assessment.