You cant know without taking a test to check for HCG. If you have an ultrasound scan the baby can be seen, later the fetal heart can be heard by Doppler, and later still the baby can be seen moving.
By taking a pregnancy test
You would know if you are pregnant without using a pregnancy test by checking the vagina,and sticking your finger up through your vagina,and then If it tastes like cheese,you are pregnant.
has your period come yet? if it has your not pregnant if it hasn't then you are (but take a test just to be sure)
you don't get your period,but seriously if you don't want to wait that long, just buy a test
You would know if you're pregnant by taking a pregnancy test. A pregnancy test can be taken from two weeks after intercourse and doesn't require you to know when your period should have started.
In theory what you just siad makes no sense at all because you dont need a test if you know your pregnant as the first part suggests.
Some women have pregnancy symptoms in which they suspect that they are pregnant. Other women have a strong maternal instinct and just "feel" pregnant. But it is hard to really know without having an accurate pregnancy test (either at home or at a doctors office).
The only way to know is by taking a pregnancy test.
You don't. The only way to know for sure is to take a home pregnancy test or see a Dr.