Ovulation calculator
This ovulation calculator allows you to find out when you'll be most fertile, and what your due date would be if you got pregnant on these dates.
Pregnancy planner
For the best chance of getting pregnant, you need to maximise the chance of your fertile egg and your partner's sperm getting together. You can only get pregnant on the few days each cycle around ovulation, when an egg is released.
When is the best time to conceive?
To increase your chances of getting pregnant, you need to get your fertile eggs and your partner's sperm together as often as possible. You can only get pregnant on the few days each cycle around ovulation, when an egg is released.
How does the menstrual cycle work?
- Your cycle starts on the first day of your period and continues up to the first day of your next period.
- At the same time, eggs begin to mature in the ovary.
- The lining of the womb thickens ready for fertilisation.
- During ovulation your cervical mucus becomes thinner and clearer to help the sperm reach the released egg.
- About 10 to 16 days before the start of your next period, an egg is released from one of the ovaries (ovulation).
- If sperm is present at the moment of ovulation, or some time during the next 24 hours, the egg may be fertilised.
- If the egg has not been fertilised, the egg is re-absorbed by the body, the hormone levels drop, and the womb lining is shed. This is the beginning of your next period.
Read more here about how pregnancy works
Conception and sex
To boost your chances of conceiving, aim to have regular sex throughout your cycle so you know that there should hopefully be good-quality sperm waiting for the time that the egg is released. An active sex life is all most people need to conceive.
If you are quite sure when you ovulate each month you can give yourself the best chance of getting pregnant by having sex in the days leading up to ovulation. Continue having sex during ovulation. After this your fertile time will be over for that cycle.
Taking a pregnancy test? Read about how pregnancy tests work.
How to spot the signs of ovulation
Ovulation usually happens about 10 to 16 days before the start of your next period, so it helps to know your cycle length before you start trying to conceive.
You may never have considered when you might ovulate within your cycle, and if you have been using a hormone contraceptive such as the Pill, you won’t have had a natural menstrual cycle for a while.
As a first step, mark on your ovulation calendar the dates that you bleed during a period. You can then count how many days from the first day of your period to your next period to work out the length of your cycle.
Cervical mucus changes
The cervix secretes mucus throughout the menstrual cycle, starting off sticky white and gradually becoming thinner and clearer.
Before and during ovulation the mucus increases and becomes much thinner, slippery and stretchy. Women often compare it to raw egg white.
This thinner mucus is designed to help the sperm swim easily through it. It indicates that you are in your fertile phase, so this is the time to have sex if you want to get pregnant, but use contraception if you do not!
The last day you notice the wetter secretions is sometimes known as ‘peak day’ and for most women this occurs very close to the time of ovulation.
Temperature
You can also find out about your menstrual cycle by keeping a note of your temperature each morning when you wake up. Your temperature rises by about 0.2°C when ovulation has taken place.
As it is only an indicator that you have ovulated, and doesn’t tell you when your fertile time starts, this is not very useful for most women.
Using ovulation test kits (also known as ovulation predictor kits)
Ovulation predictor kits are available from chemists and are fairly simple to use. They work by detecting a hormone in your urine that increases when ovulation is about to take place.
The simplest ovulation test kits check for luteinising hormone (LH), which surges 24-36 hours before ovulation. This will help to identify the best two days for conception, although a woman can be fertile for a day or so before and after this time.
It is best to become familiar with your usual menstrual cycle to help figure out when you should start testing. If you have an irregular cycle then an ovulation predictor kit can help you identify the time of ovulation, but expect to use more of the test strips.
FOUND THIS HELPFUL?
We’re committed to providing clear, up-to-date information for every woman who needs it - for free. But we do need support. For just £5, you can help us provide more advice and support to those in need.
Planning for pregnancy?
A tool for women who are planning a pregnancy that will tell you all you need to know about how to improve the health of your future pregnancy and child/ren.
- Macdonald S, Macgill-Cuerden J (2012) Mayes’ midwifery: a textbook for midwives, 14th edition, London Balliere Tindall
Review dates
Last reviewed: 13 June, 2017
Next review: 13 June, 2020
Read more about getting pregnant
-
How to know when you are pregnant
How do you know whether you're pregnant or not? If you've been trying to get pregnant, there are a few ways to find out whether you're pregnant. -
Taking a pregnancy test
Pregnancy tests work by looking for a hormone called human chorionic gonadotrophin (hCG). This hormone is only made in your body when you are pregnant. -
‘Media glamourises pregnancy at advanced ages,’ study suggests
Researchers say women are being misled into thinking pregnancy is more straightforward past the age of 35 than it is. -
Planning a pregnancy
If you've decided you're ready to start a family, find out how to get pregnant and some of the lifestyle changes that might help you.