Merge Lists

What is the Merge Lists Tool?

The merge lists tool is a free, browser-based utility that combines two one-item-per-line lists into a single clean list. Paste two columns from a spreadsheet, CSV exports, email lists, keyword lists, or tag sets, choose a merge mode, and instantly get one usable output. Everything runs locally in your browser — your data never leaves your device.

It is one of the fastest ways to merge two lists online without opening spreadsheet formulas. Combine lists by stacking them, alternating them, deduplicating them into a union, or finding the items they share.

Four Merge Modes

• Concatenate (A + B): Appends all of List B after List A in original order. The simplest way to combine two exports into one sequential list.
• Union (unique from both): Returns every unique item across both lists — equivalent to a SQL UNION. Perfect for building a clean master list of tags, keywords, emails, or IDs without duplicates.
• Intersection (common only): Returns only the items that appear in both lists — equivalent to a SQL INNER JOIN. Use it to find shared emails, matching IDs, or overlapping products.
• Interleave (alternate): Alternates items from each list — A₁, B₁, A₂, B₂ — great for schedules, quizzes, rotations, or paired content. When lengths differ, the remaining items are appended.

How to Merge Two Lists Online

1. Paste List A into the first input, one item per line.
2. Paste List B into the second input, one item per line.
3. Choose a merge mode — Concatenate, Union, Intersection, or Interleave — and the result updates instantly.
4. Adjust options: trim items, remove empty lines, remove duplicates, sort A–Z, or toggle case-sensitive matching.
5. Swap lists if you need to switch their order, then Copy or Download the merged result.

Common Use Cases

• Combining two CSV column exports, copied spreadsheet ranges, or CRM dumps into one stacked list.
• Building a master list of unique keywords, domains, tags, or emails without duplicates.
• Finding overlap between two lists, such as common email addresses or shared product IDs.
• Alternating speakers, quiz questions, or assignments from two equal-length sources.