Spaces, Underscores, or Hyphens in UTM Values?

Spaces in URLs are encoded, which can make campaign links harder to read and copy. Most teams choose underscores or hyphens for multi-word values.

Common options

• summer_sale is explicit and easy to scan in reports.
• summer-sale is readable and works well if used consistently.
• summer sale may become encoded and less convenient to inspect.

Which should you choose?

There is no universal winner. Pick one convention, document it, and do not alternate between separators for similar values. This matters more than the separator itself.

Keep the convention narrow

Do not allow each person to choose independently. A short rule such as “lowercase with underscores” is easy to teach and audit.

Use the BestUTM builder to encode values safely and keep your campaign naming guide nearby.

Choose for the whole workflow

Consider how values look in URLs, spreadsheets, exports, and analytics filters. Underscores are explicit, while hyphens are compact. Both are workable when the team uses one consistently.

Write the decision in the naming guide and make the builder or template follow it by default.

A repeatable review process

Review the link before publishing, immediately after it goes live, and again when the campaign report is first checked. These three moments catch different problems: naming errors, redirects or page issues, and unexpected reporting behavior.

Write down the correction instead of fixing one URL silently. A short record helps the whole team avoid repeating the same mistake in the next campaign.

Avoid hidden characters

Copied values can contain leading spaces, trailing spaces, non-breaking spaces, or punctuation that looks normal in a document but creates a different URL value. Paste into the builder, inspect the generated link, and keep source values simple.

This is another reason a controlled list is safer than free-form names for source and medium.