The Best Time to Have Sex to Conceive

When you are trying to conceive, advice about timing can start to feel like homework: which day, how often, what time, which position. The research behind it is reassuringly simple. There is a short window when sex can lead to pregnancy, the best days sit just before ovulation, and a relaxed rhythm through that window works about as well as a strict one.

When is the best time to have sex to get pregnant?

The best time is in the two days before ovulation and on ovulation day. In the landmark study of 221 women trying to conceive, every pregnancy came from sex during the six days ending on ovulation day, and the chance of conception rose from about 10% for sex five days before ovulation to about 33% on ovulation day.¹ ASRM reports peak fertility from sex within two days before ovulation.² When researchers corrected for errors in pinpointing ovulation, the single best day was the day before it, and the odds fell close to zero after ovulation.³

The reason is timing on both sides. Sperm can survive for several days, but the egg lives only about 12 to 24 hours after release.⁴ Sex a little early means sperm are already waiting when the egg arrives. Sex late can miss it.

How often should you have sex when trying to conceive?

Every one to two days during the fertile window. ASRM states that the chance of pregnancy rises with frequency and is highest with sex every one to two days in the window, and that couples should not be told to limit how often they have sex.² In the 1995 study, cycle pregnancy rates were similar with sex daily, every other day and even every three days in the window, and lowest when sex happened only once.²

If tracking your window is not for you, ASRM notes that sex two to three times a week throughout the cycle gives results that are nearly as good.²

Does saving up sperm help?

No. ASRM explains that abstinence of more than five days may lower sperm counts, while intervals as short as two days are linked to normal sperm densities.² In a study of almost 10,000 semen samples, men with normal semen quality kept normal concentration and motility even with daily ejaculation; after 10 or more days of abstinence, semen quality started to deteriorate.² Frequent sex in the window does not use up fertility.

Do position, orgasm or lying down afterwards matter?

No. ASRM states there is no evidence that sexual position affects fertility, because sperm are found in the cervical canal within seconds of ejaculation regardless of position.² Sperm deposited near the cervix at mid-cycle have been found in the fallopian tubes within 15 minutes.² The common belief that lying on your back after sex helps sperm reach the egg "has no scientific foundation," in ASRM's words.² Female orgasm may help sperm transport, but there is no known link between orgasm and fertility.²

What about lubricant? Some lubricants reduce sperm movement in lab tests, but ASRM notes that lubricant use was not shown to lower monthly pregnancy rates in couples trying to conceive.² If you want to be cautious, choose one labeled fertility-friendly.

Should you time sex with ovulation tests?

They can help, as long as they do not take over. A 2023 Cochrane review found that timing sex with urine ovulation tests probably increases the chance of a live birth compared with not predicting ovulation (risk ratio 1.36, one trial of 844 women, moderate-quality evidence), in women under 40 trying for less than 12 months.⁵ The evidence for timing with charting methods such as temperature and mucus was too limited to draw a conclusion.⁵

ASRM adds a caution: tying sex to a strict schedule can raise stress and reduce sexual satisfaction, so tracking should guide frequent sex rather than replace it.² A practical rule is to start every-other-day sex when your window is due to open, and add the day of your first positive LH test and the day after. See how long after an LH surge you ovulate and when to take an ovulation test. If you want a device that also confirms ovulation, look for a monitor that reads progesterone (PdG) as well as LH.

A simple plan by cycle length

Use the calculator to estimate your window, then cover it with sex every one to two days.

The calendar method places ovulation 14 days before the next period and the fertile window on the five days before it, so cycle days 9 to 14 in a 28-day cycle and 11 to 16 in a 30-day cycle.² The calculator uses the same count.

The calendar is only a starting estimate: real ovulation days vary from cycle to cycle, which our fertile window guide explains in detail. If you also check cervical mucus, the days with clear, slippery mucus are your best days.⁸

Does age change the best time?

Not the timing, but the odds. In a study of 782 couples and 5,860 cycles, the fertile window was the same six days at every age, but the chance of pregnancy on each fertile day was about twice as high for women aged 19 to 26 as for women aged 35 to 39.⁶ Fertility for men over 35 was also lower after accounting for the woman's age.⁶

When to see a doctor

ACOG recommends an infertility evaluation after a year of regular unprotected sex if you are under 35, after six months if you are 35 or older, and a conversation with your doctor right away if you are over 40.⁷ Read when to see a fertility specialist for what to expect, or return to the Try hub.