I am not really sure of your question...

If you have a 30 day cycle that means your cycle day 1 is the first day of your period. On a 30 day cycle in a perfect world you would ovulate 14 days prior to your next bleed.

However, that is not an accurate & may be an ineffective way to TTC.

Have a read of "The Billings Method" and get to know your body - your cervical mucous changes throughout your cycle. When your body begins to get ready for conception your cervical mucous changes to look a lot like egg white - slippery and very wet. This is the mucous needed to carry the sperm up into the tubes waiting for your follicle to rupture with a lovely ovum! Your mucous will change dramatically after your fertile window closes back to thicker, whiter mucous.

You can take your basal temperature evry day before rising and chart it - fertility friend have some great tools to have a look at - just google it.

You can use OPK's or "ovulation predictor kits. They look like a pregnancy test and are used to detect your LH surge. This surge occurs just prior to ovulation and causes the follicle to rupture and release your ovum... So using these can show you your really fertile window.

2nd daily BD can get really really really draining and tiresome (trust me I have done it ) and is unnecessary if you get to know your body. This frees you up to enjoy making love.

Goodluck on your journey...