Merge Two Texts: Append, Interleave, or Pair Their Lines
Combining two pieces of text sounds trivial until the combination has structure: pairing every question with its answer, gluing a column of names to a column of emails, alternating original and translated lines, or simply stacking two documents in order. Spreadsheets can do some of this with formulas; doing it by hand means hundreds of copy-paste operations. This free merger takes two texts and combines them in one of three ways — appending one after the other, interleaving their lines alternately, or joining corresponding line pairs with a separator — turning structured merges into a single click. Everything runs locally in your browser.
Append Mode: One Text After the Other
Append is the simplest merge: the full content of Text A followed by the full content of Text B, separated by a line break. Use it to stack chapters, concatenate exported fragments, combine two lists into one before deduplicating, or assemble a document from parts drafted separately. It replaces the open-both-files-and-paste routine with one operation and guarantees nothing is lost or reordered in transit.
Interleave Mode: Alternating Lines
Interleave weaves the two texts together line by line: the first line of A, then the first line of B, then the second of A, and so on. When one text runs out, the remaining lines of the longer one follow in order. This layout is the standard format for bilingual study text — original above, translation below, repeating — and for call-and-response scripts, side-by-side comparison reading, and quiz formats where a question line alternates with its answer line.
Pair Mode: Joining Corresponding Lines
Pair mode joins line 1 of A with line 1 of B on a single output line, placing your separator between them, then line 2 with line 2, and so on — effectively zipping two columns into one. With a dash separator, names and roles become labeled entries; with a comma, two columns become CSV rows; with a tab, the output pastes into a spreadsheet as two columns; with @ between user names and domains, you assemble email addresses. Any leftover lines from the longer text are appended unpaired so no data silently disappears.
Preparing Columns from Spreadsheets
The typical source of paired data is a spreadsheet: copy column one into Text A, column two into Text B, and pair them with the separator the destination needs. This direction — from columns to delimited lines — complements what spreadsheets do poorly without formulas. Enable Skip empty lines so blank cells copied at the end of a column do not produce dangling separators, and check the output statistics to confirm the line count matches your row count.
Keeping Line Counts Aligned
Interleave and pair modes assume the two texts correspond line by line, so a missing or extra line shifts every pairing after it. Before merging, glance at the line counters under each input: equal counts mean clean pairing. If they differ, the usual culprits are a trailing blank line, a header row present in one column only, or a wrapped line that became two. The merger still completes — extra lines are appended at the end — but aligning counts first produces the result you actually intended.
Privacy and Client-Side Processing
Both texts are processed entirely in your browser with JavaScript; nothing is uploaded, stored, or logged. Contact lists, translations in progress, and internal documents are safe to merge here. The texts are cleared from memory when you close or refresh the page, and the download button saves large merged outputs to a file directly.