Ay sis, nakaka-relate ako dito kasi irregular din ako! Honestly, ang calculators ay helpful para sa rough estimate lang, pero if irregular ang period mo, ang best talaga is i-confirm with your OB through ultrasound, yan ang most accurate way malaman kung exactly kailan conception at when baby developed, especially kung walang clear LMP mo. Marami sa amin dito gamit na rin ng reverse calculator from due date (kung meron ka man), pero pag irregular talaga, ang dating methods from the scan lang ang pinaka-reliable; your doctor might also ask about when you think you conceived or when nakita mo positive pregnancy test para ma-triangulate nila better. Abangan mo na lang ang first ultrasound mo sis, doon talaga magiging malinaw lahat!