i think its quite hard to pinpoint the exact day because you can never really be sure when you ovulate or if you ovulate on time or a little late, the only way you could be a100% sure would be to of had IVF, life would be so much easier if wecould pinpoint the exact day
Yes there are charts on internet look them up
You can work out roughly the date of conception. But that doesn't ness mean that is the day you had sex. Sperm can live inside you for up to a week. Usually takes around 2/3 days between.