Convert date format

100% local. Your text never leaves this browser tab.

Paste a list of dates and every one is reformatted at once. This page turns MM/DD/YYYY into YYYY-MM-DD, the ISO 8601 order that sorts correctly as plain text. It uses one pattern rule you can adjust for any order, and it runs entirely in your browser.

The rule

One pattern reorders every date

The tool above uses a single pattern rule: capture the three numbers, then output them in the order you want.

Find (pattern):   (\d{1,2})/(\d{1,2})/(\d{4})
Replace with:     $3-$1-$2

MM/DD/YYYY  ->  YYYY-MM-DD   (used above)

Same idea, other orders:
  DD/MM/YYYY -> YYYY-MM-DD :  replace with  $3-$2-$1
  YYYY-MM-DD -> DD/MM/YYYY :  find (\d{4})-(\d{2})-(\d{2}), replace $3/$2/$1

Reformat, not just reorder (name a group, then re-date it):
  find (?<d>\d{8})  replace ${d:date(yyyyMMdd->dd MMM yyyy)}
  20261231  ->  31 Dec 2026   (reparses the date, month name and all)

$1, $2 and $3 are the captured numbers, reordered however your target needs. To change the layout itself (add a month name, pad, or read a compact date), name the group and reformat it with ${name:date(FROM->TO)}.

Why ISO order

Year first, so it sorts

ISO 8601 sorts right

Putting the year first (YYYY-MM-DD) means dates sort chronologically as plain text, which is why databases, logs and file names prefer it.

Works on a whole list

Every line that matches the pattern is converted in one pass, so you can paste a column of dates and reformat them all at once.

Reformat, not just reorder

Name a captured date and re-date it with ${d:date(yyyyMMdd->dd MMM yyyy)}: it reparses the value and re-emits it, so you can turn 20261231 into 31 Dec 2026, month name included, not only swap the pieces around.

The Windows app

Put it on a hotkey

☕ Every date in the right format on a hotkey, for the price of a coffee. Yours forever.

Download this exact setup as a ready-made Date to ISO profile. Give it a global hotkey in the Windows app and any list of dates you copy is reformatted the instant you paste. Same engine as above, entirely offline.

Get the Windows app →
Pay once, €3.39, no subscription. If the app doesn’t open, the profile is saved to your downloads, just import it.
FAQ

Questions, answered plainly

How do I convert a date to YYYY-MM-DD?

Paste your dates above and each MM/DD/YYYY date becomes YYYY-MM-DD instantly. The tool uses one pattern rule you can copy, or export as a profile for the Windows app.

How do I change the output order?

Reorder the capture groups in the replacement: $1 is the first captured number, $2 the second and $3 the third, so $3-$1-$2 gives year, month, day.

Why use YYYY-MM-DD instead of MM/DD/YYYY?

YYYY-MM-DD is the ISO 8601 standard and it sorts in date order when treated as plain text, unlike MM/DD/YYYY. It also avoids the confusion between US and European day and month order.

Can I reformat a date, not just reorder the numbers?

Yes. Name the date group and reformat it with a date token: ${d:date(yyyyMMdd->dd MMM yyyy)} reparses 20261231 and writes 31 Dec 2026, so you can convert between any two layouts, including month names, not only swap the pieces.

More generators: GUIDs, date formats, random strings, sequential numbers and today's date.