Keyword Combiner — User Guide

Keyword Combiner — User Guide

Version: 1.0
Author: Glenn Leader
Last Updated: 25th January 2025

Table of Contents

  1. Introduction
  2. What It Does
  3. When to Use It
  4. How to Use It
  5. Options Explained
  6. Examples
  7. Tips and Best Practices
  8. Troubleshooting
  9. Technical Details

1. Introduction

Keyword Combiner is a free tool that generates all possible combinations from multiple word lists. As part of the Phrase Foundry toolkit, it’s designed to save you time when creating keyword variations for PPC campaigns, product names, or domain brainstorming.

This keyword combination tool is simple but powerful. Simply feed it 2-5 word lists, and it’ll generate every possible combination. There’s no complex setup, no subscriptions, no nonsense.

2. What It Does

Keyword Combiner takes multiple lists of words and creates a Cartesian product — that’s the mathematical term for “all possible combinations”.

Simple example:
List 1: red, blue
List 2: car, bike
Output: red car, red bike, blue car, blue bike

That’s 2 × 2 = 4 combinations. However, the tool scales up to 5 lists, which means you can generate thousands or tens of thousands of combinations in seconds.

Keyword Combiner interface showing multiple word lists being combined

Screenshot: The Keyword Combiner tool interface with sample word lists

3. When to Use a Keyword Combiner

PPC Campaigns

Creating ad groups for Google Ads or Microsoft Advertising? You need variations like “cheap red car” and “luxury blue bike”. Simply list your attributes in separate lists, and the tool does the rest.

Product Names

Brainstorming product names or SKU variants? By combining product types, colours, sizes, and materials, you can generate a complete catalogue in minutes.

Domain Brainstorming

Looking for available domains? Combine prefixes, keywords, and TLDs to generate hundreds of potential domain names quickly.

SEO Keyword Research

Building out long-tail keyword variations by combining modifiers, locations, and base terms.

4. How to Use the Keyword Combiner

Step 1: Enter Your Lists

First, the keyword combiner tool starts with 2 word lists visible. Enter one item per line in each textarea. You can paste from a spreadsheet or type manually.

Example:
List 1:

“

red

blue

green

`
List 2:
`

car

bike

truck

`

Step 2: Add More Lists (Optional)

Next, click Add List to reveal additional textareas. You can have up to 5 lists total. Keep in mind that each additional list multiplies the number of combinations.

Warning: Adding a 5th list with 10 items each in all lists = 100,000 combinations. For this reason, the tool has a safety limit to prevent browser crashes.

Step 3: Configure Options

Then, configure your preferences:

  • Separator: Choose how to join the words (space, hyphen, underscore, or none)
  • Prefix/Suffix: Add text before or after each combination
  • Case Normalisation: Convert all output to lowercase, UPPERCASE, or Title Case
  • Deduplication: Remove duplicates (case-sensitive or case-insensitive)
  • Output Limit: Set maximum combinations to generate (100-100,000)

Step 4: Generate

Click Generate Combinations and wait for the results. Once complete, the tool shows you:

  • How many items were in each list
  • Total possible combinations
  • How many were actually generated
  • Processing time in milliseconds

Step 5: Export

Finally, use Copy to copy all combinations to your clipboard, or Save to download as a text file.

5. Options Explained

Separator

Controls what appears between words from different lists.

  • Space (default):

red car

  • Hyphen:

    • red-car

  • Underscore:

    • red_car

  • None:

    • redcar

    Most SEO and PPC work uses spaces. However, hyphens are common for domain names, while underscores are rare but useful for technical IDs.

    Prefix

    Adds text to the start of every combination. Importantly, the selected separator is automatically added between the prefix and the combined words.

    Example: Prefix = buy, Separator = space

    Output:

    buy red car, buy blue bike
    Example: Prefix =     SKU, Separator = hyphen

    Output:

    SKU-red-car, SKU-blue-bike

    Suffix

    Adds text to the end of every combination. Similarly, the selected separator is automatically added between the combined words and the suffix.

    Example: Suffix = online, Separator = space

    Output:

    red car online, blue bike online
    Example: Suffix =     .com, Separator = none

    Output:

    redcar.com, bluebike.com

    Case Normalisation

    Transforms all output to a consistent case.

    • Keep original (default): No change
    • lowercase:

    red car online

  • UPPERCASE:

    • RED CAR ONLINE

  • Title Case:

    • Red Car Online

    Useful if your lists have inconsistent capitalisation.

    Deduplication

    Removes duplicate combinations.

    • None: Keep all combinations (even duplicates)
    • Case-sensitive: "Red Car" and "red car" are different
    • Case-insensitive: "Red Car" and "red car" are treated as duplicates

    Importantly, deduplication happens after case normalisation, so if you set case to lowercase and deduplication to case-insensitive, you'll get the smallest possible output.

    Output Limit

    Safety valve to prevent your browser from freezing.

    • Minimum: 100
    • Default: 10,000
    • Maximum: 100,000

    If your lists would generate more combinations than the limit, the tool stops at the limit and warns you accordingly.

    Pro tip: If you're hitting the limit, first consider whether you really need all those combinations. Alternatively, you should break the task into smaller batches.
    Keyword Combiner options panel showing separator, prefix, suffix and other settings

    Screenshot: Configuration options for customising your keyword combinations

    6. Examples

    Example 1: Basic PPC Keywords

    Let's start with a simple example for creating PPC ad group variations.

    List 1: buy, cheap, luxury
    List 2: red, blue
    List 3: car, bike
    Options:

    • Separator: Space
    • Prefix: (none)
    • Suffix: (none)
    • Case: lowercase
    • Dedupe: Case-insensitive
    • Limit: 10,000

    Output (18 combinations):
    `

    buy red car

    buy red bike

    buy blue car

    buy blue bike

    cheap red car

    cheap red bike

    cheap blue car

    cheap blue bike

    luxury red car

    luxury red bike

    luxury blue car

    luxury blue bike

    `

    Example 2: Domain Names

    Next, here's how to generate domain name ideas using the "None" separator.

    List 1: get, find, top
    List 2: cheap, best
    List 3: cars, bikes
    Options:

    • Separator: None
    • Prefix: (none)
    • Suffix: .com
    • Case: lowercase
    • Dedupe: Case-insensitive
    • Limit: 10,000

    Output (18 combinations):
    `

    getcheapcars.com

    getcheapbikes.com

    getbestcars.com

    getbestbikes.com

    findcheapcars.com

    findcheapbikes.com

    findbestcars.com

    findbestbikes.com

    topcheapcars.com

    topcheapbikes.com

    topbestcars.com

    topbestbikes.com

    `

    Example 3: Product SKUs

    Finally, this example demonstrates generating product SKUs with prefixes, suffixes, and uppercase formatting.

    List 1: shirt, trousers
    List 2: red, blue, black
    List 3: S, M, L, XL
    Options:

    • Separator: Hyphen
    • Prefix: SKU-
    • Suffix: -2025
    • Case: UPPERCASE
    • Dedupe: None
    • Limit: 10,000

    Output (24 combinations):
    `

    SKU-SHIRT-RED-S-2025

    SKU-SHIRT-RED-M-2025

    SKU-SHIRT-RED-L-2025

    SKU-SHIRT-RED-XL-2025

    SKU-SHIRT-BLUE-S-2025

    ...

    “

    7. Tips and Best Practices

    Start Small

    Before generating 50,000 combinations, first test with 2-3 items per list to make sure your options are configured correctly.

    Mind the Maths

    Combinations multiply fast. For example, 5 lists with 10 items each = 100,000 combinations. That’s a 3MB text file. Therefore, make sure you actually need that many.

    Use Deduplication

    If your lists overlap (e.g., List 1 has “red car” and List 2 has “car”), you’ll get duplicates. In this case, turn on deduplication to clean them up.

    Prefix/Suffix for Modifiers

    Instead of adding “buy” to every item in List 1, use the Prefix field. It’s faster and cleaner. Additionally, the separator you’ve chosen will automatically be added between the prefix/suffix and your combinations.

    Export Before You Lose It

    Once you’ve generated your combinations, copy or save them immediately. Otherwise, if you refresh the page, they’re gone.

    Chain with Other Tools

    Copy the output and paste it into Keyword Scrubber for further cleaning. Alternatively, you can use Keyword Bloom for expansion.

    8. Troubleshooting

    “Minimum 2 lists required”

    You need at least 2 word lists to generate combinations. Therefore, make sure you’ve filled in List 1 and List 2.

    “Output limited” warning

    Your lists would generate more combinations than your output limit allows. To fix this, either:

    1. Increase the output limit (up to 100,000)
    2. Reduce the number of items in your lists
    3. Split the task into multiple batches

    Browser freezes or slows down

    You’re probably trying to generate too many combinations. Consequently, you should reduce your list sizes or output limit. Remember: 10 items in 5 lists = 100,000 combinations. That’s a lot of text for your browser to handle.

    Combinations look wrong

    First, check your separator setting. If you’re seeing “redcar” instead of “red car”, you’ve set the separator to “None”.

    Duplicate combinations appearing

    Turn on deduplication. However, if you’re still seeing duplicates, check if your lists themselves contain duplicates.

    9. Technical Details

    How It Works

    The tool uses a Cartesian product algorithm. Specifically, it takes the first list and combines each item with every item in the second list. Then it takes those results and combines them with the third list, and so on.

    Example:

    List 1: [A, B]

    List 2: [1, 2]

    Step 1: Combine List 1 with List 2

    Result: [A1, A2, B1, B2]

    If there’s a List 3: [X, Y]

    Step 2: Combine previous result with List 3

    Result: [A1X, A1Y, A2X, A2Y, B1X, B1Y, B2X, B2Y]

    Performance

    The tool can generate 10,000 combinations in under 50ms on modern hardware. However, larger combinations (50,000+) may take several hundred milliseconds.

    Limits

    The tool has the following technical limits:

    • Maximum lists: 5
    • Maximum output: 100,000 combinations
    • Maximum list size: No hard limit, but performance degrades with very large lists (10,000+ items)

    Browser Compatibility

    The tool works in all modern browsers (Chrome, Firefox, Safari, Edge). However, Internet Explorer is not supported.

    Data Privacy

    All processing happens in your browser. As a result, nothing is sent to a server. Consequently, your word lists and combinations are never stored or transmitted.

    Useful Resources

    To further expand your keyword research skills, check out these resources:

    Need More Help?

    If you’re stuck, check the other Phrase Foundry tools:

    • Keyword Scrubber — Clean and deduplicate your lists before combining
    • Keyword Bloom — Expand keywords with seed substitutions

    Alternatively, for bugs or feature requests, use the contact form on the Phrase Foundry website.

    Version History

    • v1.0 (25th January 2025) — Initial release