March in the birth records
March accounts for 5,172,961 births, or 8.32% of the 62,187,024 records in the SSA 2000–2014 sample. Within this month, March 21 is the most common date, ranked #130 nationally. March 31 has the fewest total records and ranks #339. The table above includes all 31 dates, not just those two extremes.
What makes this month worth a closer look
March returns to 31 days after February. Comparing whole-month totals without allowing for that length would give March an automatic advantage. This table instead asks about March 1, March 2 and every other date individually. A person with a March birthday can see the exact row that applies rather than relying on a label for the season.
March 1 is sometimes used to celebrate a February 29 birthday in an ordinary year. The source counts actual recorded birth dates, not celebration choices, so we never move leap-day births into the March 1 row. For that separate result, use February 29. Each date here keeps its own recorded count.
Read your row and make a card
Rank #1 is most common across all 366 dates. “1 in” divides all birth records by the records for that specific date; the daily-average column divides by the number of times the date occurred. A higher “rarer than” percentage means more other dates had higher counts. These are different ways of describing the same historical sample, not estimates of everyone alive today.
Select your date in the table to open the birthday calculator. Save a portrait or landscape result, or combine it with your name. The complete methodology and original FiveThirtyEight source stay available for anyone who wants to check the numbers.