DedupeLines
Free · No signupBrowser-local · zero upload · 80 MB cap

Remove blank lines, online

Paste any text, get the blank lines stripped out — including the "looks empty but has spaces" ones. Unlike the home-page dedupe, this tool keeps every non-blank row intact — nothing else is touched.

Input · 0 lines
output · 0 lines
Paste something on the left — results stream in here.

Or press Ctrl+Enter

Input lines0
Blank lines0
Output lines0

When to use this tool

guide
01 / Log & CSV cleanup

Logs and CSV exports often arrive with random blank rows between data. Strip them in one paste so the next tool downstream sees a tidy block.

02 / AI / LLM output

Chat models love padding output with empty lines for "readability". Paste, strip, and you have clean rows ready for a spreadsheet or downstream parser.

03 / Email list import

Exports from CRM, Sheets or Mailchimp often include trailing empties. Clean them up before re-importing to avoid validation errors.

04 / Excel / Sheets paste

Copying a non-contiguous range from a spreadsheet pastes blank rows where the gaps were. Drop them here, get a continuous list back.

How it works

three steps
  1. 01

    Paste your text

    Logs, CSV exports, AI output, scraped content — anything with blank rows mixed in.

  2. 02

    Choose trim

    Trim is on by default — leading/trailing whitespace on each remaining line gets stripped. Toggle off to preserve the formatting of every non-empty row.

  3. 03

    Hit Run

    Empty lines and whitespace-only lines vanish. Order of the remaining rows is preserved.

Under the hood

engine notes
Definition of "blank"
Empty string OR matches /^\s*$/
Catches tabs, regular spaces, and Unicode whitespace (NBSP, en-space, em-space, etc.). A line with only invisible Unicode whitespace is still considered blank.
Throughput
100K lines cleaned in ≈100 ms on a 2024 M3 MacBook Air
Single linear scan, one regex test per line. No allocation per dropped line.
Threading
Web Worker for files ≥ 2 MB or ≥ 100K lines
Above the desktop threshold, the page stays interactive while a Worker processes the file and delivers the result as a .txt download.

Privacy & limits

what stays where

Everything runs in your browser. Nothing about the blank-line scan touches the network — the regex test happens line by line, in memory. After page load the tool works offline. 80 MB hard cap per run.

Frequently asked

answered

What counts as a blank line?

Two conditions: (1) the string is exactly empty, or (2) it matches the regex /^\s*$/ — meaning it contains only whitespace characters. This catches plain spaces, tabs, and invisible Unicode whitespace like NBSP (U+00A0), en-space, em-space, and zero-width space.

Does it modify the non-empty lines?

Only if the trim toggle is on (it is, by default). With trim off, every non-blank line is preserved exactly as-is — leading/trailing spaces stay. The tool only changes the lines it removes, not the lines it keeps.

How is this different from `grep -v "^$"`?

`grep -v "^$"` catches only truly empty lines, not whitespace-only ones — a line containing a single space passes through `grep -v "^$"` but is removed by this tool. Closer to `grep -Ev "^\s*$"` if you want a shell one-liner equivalent.

Is my text uploaded anywhere?

No. All processing happens in your browser tab. Once the page is loaded, the blank-line scan is local — there is no upload step, and the telemetry layer cannot see your input. The page works offline after loading.