Helping You Monitor Your Fertility

Recommended Pages for Further Reading


"Charting your fertility symptoms can help suggest when it is appropriate to begin taking ovulation tests to confirm suspicions of approaching ovulation."


Ovulation Calendar


Most ovulation predictor kits (OPKs) work by detecting lutenizing hormone (LH). LH levels surge immediately before ovulation. By detecting this surge, home ovulation tests can offer advance notice of ovulation. LH levels surge

Overview of Home Ovulation Testing

Ovulation tests require repeated testing until you receive a positive test result. Once the result is positive, you know that you will likely ovulate in the next 24 to 36 hours. Planning intercourse during the next 48 hours will help maximize the odds of conception.

If you have been charting your fertility, you may already have an idea when in your cycle ovulation occurs. Otherwise you can use the principles of the rhythm method to roughly estimate your ovulation date and begin ovulation testing a few days earlier. You can subtract the luteal phase length (typically 14-days) from your average cycle length to roughly estimate the cycle day of ovulation. You will want to begin testing earlier though to detect ovulation, so you will subtract an additional 3 days. You should consider testing then.

Example: If you have a 30-day cycle on average, the rhythm method would roughly place ovulation around cycle day 16 (30 minus 14 equals 16). Subtracting 3 additional days yield cycle day 13. Therefore you should begin testing on cycle day 13.

This is reasonable to estimate if your cycle length is regular. If you have irregular cycles, this calculation may be completely ineffective. With ovulation tests, the only option is to test early and often. This can become quite expensive in the case of long, irregular cycles. As an alternative, you should consider tracking cervical mucus or other symptoms to help anticipate ovulation. Ovulation testing can then be performed at that time if still desired.


  1. A few days before ovulation is expected, begin testing.
  2. Continue testing until you receive a positive test result.
  3. For the best chances of conceiving, plan intercourse following the positive test result over the next 48-hours. Ovulation is likely to occur 24-36 hours after the positive test.

Recording on Charts

Most charts will include an area for you to record ovulation test results. If so, mark down positive or negative test results using a '+' or '-' sign as appropriate. Simply leave days blank if no test was taken.


  • Ideal for couples trying to conceive since it detects ovulation before it occurs
  • Fairly simple to use. Tests are either positive or negative.
  • Tests are very effective since they measure LH levels directly


  • Tests can be expensive
  • Daily testing may become impractical if cycles are irregular in length. Tracking of other fertility symptoms should be considered to help identify when to administer tests.