Split a date string into day, month and year in C# and JavaScript

C# & ADO.NET · By the Postback Notes editorial team · Published 2026-08-25

Given "25/12/2026", it is tempting to split on / and take the three parts. It works until the input arrives as 12/25/2026, 2026-12-25 or with a time attached. Parse the string into a date with an explicit format first; then day, month and year are properties.

C#: parse, then read the parts

using System.Globalization;

string input = "25/12/2026";
if (DateTime.TryParseExact(input, "dd/MM/yyyy", CultureInfo.InvariantCulture,
                           DateTimeStyles.None, out DateTime date))
{
    int day = date.Day;        // 25
    int month = date.Month;    // 12
    int year = date.Year;      // 2026
    string monthName = date.ToString("MMMM", new CultureInfo("en-GB")); // "December"
    DayOfWeek dow = date.DayOfWeek;                                    // Friday
}
else
{
    // not a valid date in that format: "31/02/2026" is rejected too
}

MM is the month and mm the minutes; mixing them up is a classic bug.
Pass several accepted formats as an array: new[] { "dd/MM/yyyy", "d/M/yyyy", "yyyy-MM-dd" }.
With CultureInfo.InvariantCulture, the / in the format matches a literal slash. With another culture, it means "that culture's date separator", which may be a dot or a dash.
On .NET 6 and later, DateOnly.TryParseExact represents a date without a time.

Why plain Split is fragile

string[] parts = input.Split('/');
int day = int.Parse(parts[0]);   // works for "25/12/2026"...
// ...but gives day 12, month 25 for "12/25/2026", and throws for "2026-12-25"

Splitting gives you three numbers but no guarantee they form a date: 31/02/2026 splits happily. Parsing validates the date as a whole.

From a TextBox in Web Forms

An asp:TextBox with TextMode="Date" renders an HTML date input, which always posts yyyy-MM-dd regardless of how the browser displays it, so parse with that format:

DateTime.TryParseExact(txtBirth.Text, "yyyy-MM-dd", CultureInfo.InvariantCulture, DateTimeStyles.None, out DateTime birth);

For three separate drop-down lists (day, month, year), build the date with new DateTime(year, month, day) inside a try/catch for ArgumentOutOfRangeException, or check day <= DateTime.DaysInMonth(year, month) first.

JavaScript

function parseDmy(s) {
  var m = /^(\d{1,2})\/(\d{1,2})\/(\d{4})$/.exec(s.trim());
  if (!m) return null;
  var d = +m[1], mo = +m[2], y = +m[3];
  var date = new Date(y, mo - 1, d);              // months are 0-based in JavaScript
  // reject 31/02 and similar, which Date silently rolls over into March
  return date.getFullYear() === y && date.getMonth() === mo - 1 && date.getDate() === d ? date : null;
}
var dt = parseDmy("25/12/2026");
if (dt) console.log(dt.getDate(), dt.getMonth() + 1, dt.getFullYear()); // 25 12 2026

Splitting other strings into arrays is covered in Split a string into an array.

Official documentation

Microsoft Learn: DateTime.TryParseExact, Custom date and time format strings, DateOnly
MDN: Date