What week of pregnancy are you in right now?

How is pregnancy week calculated?

From your last menstrual period (LMP), current week = number of days since the first day of your LMP, divided by 7, rounded down. If you instead know your due date, this calculator first back-calculates an equivalent LMP (due date minus 280 days) and then works from that same rule — the same math the Pregnancy Due Date Calculator uses in reverse.

Why do doctors count from the last period instead of conception?

Medical convention counts gestational age from the first day of the last menstrual period because that date is usually known with reasonable precision, while the exact conception date rarely is. Conception typically happens about two weeks after LMP, so you're considered a couple of weeks "pregnant" before conception technically occurs — standard practice, not an error.

How is this different from your Due Date Calculator?

The Pregnancy Due Date Calculator focuses on calculating and confirming your due date from several possible starting points — LMP, a known conception date, or an IVF transfer date. This tool assumes you already have one of those dates and instead focuses on week-by-week progress right now: your current gestational week, trimester, days remaining, and an illustrative size comparison for this stage of the pregnancy.

Are size comparisons medically precise?

No — fruit and vegetable size comparisons are illustrative and popular in pregnancy apps and books, but actual fetal size varies meaningfully from pregnancy to pregnancy. Your provider's ultrasound measurements are the accurate source for size and growth tracking, not a produce-aisle comparison.

Worked example: an LMP of March 10 checked on July 16 is 128 days later, or floor(128 ÷ 7) = 18 completed weeks — squarely in the second trimester, with a due date of December 15 (LMP + 280 days) about 152 days away at that point, and a size comparison of roughly "lemon to banana" for the week-14-to-20 range.