Regex to Replace Multiple Spaces with a Single Space

Replace Multiple Spaces with One

Pasted text, copied tables, and OCR output often contain runs of spaces that should be normalized to a single space.

Collapse Any Run of Whitespace

\s+

text.replace(/\s+/g, " ") replaces every run of whitespace (spaces, tabs, newlines, etc.) with a single space.

Spaces Only (preserve newlines)

[ \t]+

text.replace(/[ \t]+/g, " ") collapses runs of spaces and tabs while keeping line breaks intact.

Tested Examples

Input	\s+	[ \t]+
"hello world"	"hello world"	"hello world"
"a\t\tb"	"a b"	"a b"
"line1\n\n\nline2"	"line1 line2"	"line1\n\n\nline2"
" leading trailing "	" leading trailing "	same

Trim and Collapse Together

text.replace(/\s+/g, " ").trim()

Or in one regex pass:

text.replace(/^\s+|\s+$|(\s)\s+/g, "$1")

Preserve Paragraph Breaks

If you want to collapse single line breaks but keep blank lines (paragraph separators):

text.replace(/[ \t]+/g, " ").replace(/\n{3,}/g, "\n\n")

Performance

\s+ is one of the safest patterns: no nested quantifiers, no alternation. Even on multi-megabyte inputs the regex engine processes it in linear time.

Unicode Whitespace

\s covers ASCII whitespace plus form feed and vertical tab. To also include Unicode space characters (non-breaking space, em space), use the u flag and \p{White_Space}:

text.replace(/\p{White_Space}+/gu, " ")

This catches the troublesome \u00A0 (non-breaking space) commonly pasted from Word.