Predict ovulation timing, fertile window, and success rates when taking Clomid (clomiphene citrate). Estimate LH surge and best days for conception.
Clomid (clomiphene citrate) is one of the most commonly prescribed fertility medications. It works by stimulating the pituitary gland to release more FSH and LH, which triggers ovulation. The Clomid Ovulation Calculator helps you predict when ovulation is most likely to occur based on your dosing protocol, cycle length, and other factors.
Timing is critical when using Clomid. Ovulation typically occurs 5–10 days after the last Clomid pill, creating a specific window for timed intercourse or intrauterine insemination (IUI). This calculator maps out your entire cycle timeline—from when to take your medication to when to begin ovulation predictor kit (OPK) testing, your fertile window, and when to schedule a progesterone confirmation test.
Understanding your Clomid cycle timeline and expected success rates helps reduce the stress of fertility treatment by giving you clear, actionable information about what to expect and when. The calculator also estimates per-cycle and cumulative pregnancy rates based on your dose and cycle number.
Clomid treatment requires precise timing to maximize your chances of conception. Knowing when to expect ovulation helps you plan OPK testing, time intercourse optimally, and schedule confirmatory blood work.
This calculator takes the guesswork out of your Clomid cycle by providing a day-by-day timeline. It also gives you realistic expectations about success rates based on your specific situation.
Expected Ovulation = Last Clomid Day + 5 to 10 days Fertile Window = Ovulation Day - 2 to Ovulation Day + 1 Progesterone Test = Ovulation Day + 7 Pregnancy Test = Ovulation Day + 14
Result: Ovulation Day 12–17, Fertile Window Day 10–18
On a Days 3–7 protocol, the last pill is taken on Day 7. Ovulation is expected 5–10 days later (Days 12–17), with the fertile window spanning Days 10–18.
Clomid (clomiphene citrate) is a selective estrogen receptor modulator (SERM) that blocks estrogen receptors in the hypothalamus. This tricks the brain into thinking estrogen levels are low, prompting increased secretion of GnRH, FSH, and LH. The resulting FSH surge stimulates the ovaries to develop follicles, while the LH surge triggers ovulation.
The medication is typically taken for 5 days early in the menstrual cycle. The Days 3–7 protocol may produce more follicles, while the Days 5–9 protocol may result in a single dominant follicle that grows larger, potentially leading to better endometrial lining.
Proper monitoring is essential for Clomid treatment success. Your doctor may recommend baseline blood work (Day 3 FSH and estradiol), mid-cycle ultrasound to check follicle development, and a Day 21 progesterone test to confirm ovulation. At-home monitoring with OPKs and basal body temperature charting can supplement clinical monitoring.
If you are having IUI, timing is especially critical—insemination is typically performed 24–36 hours after the LH surge is detected by OPK or blood work.
If you have not conceived after 3–6 cycles of Clomid with confirmed ovulation, your doctor may recommend additional testing, a switch to letrozole (Femara), or advancement to injectable gonadotropins with or without IUI. In vitro fertilization (IVF) may be discussed after failed oral medication cycles.
Begin using ovulation predictor kits (OPKs) 2–3 days after your last Clomid pill. For a Days 3–7 protocol, start testing around Day 10.
Clomid can cause false-positive OPK results if you test too soon after the last pill. Wait at least 3 days after finishing Clomid before trusting OPK results.
About 8–12% per cycle for conception, with an 80% cumulative rate of ovulation over multiple cycles. The pregnancy rate per ovulatory cycle is about 15%.
Most doctors recommend up to 6 cycles of Clomid. About 75% of pregnancies occur in the first 3 cycles. After 6 cycles, other treatments are usually considered.
Higher doses may shift ovulation slightly later in the cycle. The 5–10 day window after the last pill remains the general guideline regardless of dose.
Your doctor will likely increase the dose to 100mg and then 150mg in subsequent cycles. About 50% of women who fail to ovulate at 50mg will respond to a higher dose.