Ok so I found this site online and it's very useful for hcg doubling rate and when to take pregnancy test. You have to know your ovulation date and luteal phase length to get accurate results. You can see the test timing depends on the date you ovulated, your luteal phase length and your initial hcg value. Here's the link
https://whenmybaby.com/implantation-doubling-calculator.php
https://whenmybaby.com/implantation-doubling-calculator.php
. It's accurate too taking into mind your luteal phase length and giving the date of your expected periods. Some sites just take into account our average cycle length even if we ovulate early or late. Thought it would be useful for others here.
