# Email Preview Tester

> Email preview tester: check how your subject line and preheader render in Gmail, mobile inboxes, and truncated views before you send. Free, no signup.

- **Canonical URL:** https://boringtoolskit.com/email-preview-tester/
- **Category:** Text & Developer Tools
- **Evidence level:** authored-methodology
- **Reviewed:** July 2026
- **Last verified:** 2026-09-20
- **Privacy:** Inputs and results stay in this browser unless the page clearly labels an external request.

## How it works

The simulator removes unsupported control characters, applies a documented character budget for the selected representative viewport and client card, and adds an ellipsis when a subject or preheader exceeds that simulation budget.

## Worked example

Enter a sender name, Subject A, an optional Subject B, and preheader text. Switch between compact mobile, wide mobile, and desktop to compare how the same copy may truncate in four representative inbox layouts.

## Assumptions

- Character budgets are deterministic BTK simulation limits, not measurements of every live inbox client.
- Actual display varies with client version, device, settings, personalization, sender reputation, and email markup.
- The tool evaluates presentation only. It does not send email, inspect HTML, score spam risk, or predict inbox placement or deliverability.

## Common questions

### Does this send my email content anywhere?

No. The preview runs in your browser and does not upload, send, or automatically store the sender, subject, or preheader.

### Is this an exact Gmail, Apple Mail, Outlook, or Yahoo rendering test?

No. These are representative layouts with documented simulation budgets. Live clients can display different text lengths and styling.

### Does a good preview mean my email will reach the inbox?

No. Presentation and deliverability are different. This tool makes no spam, reputation, placement, open-rate, or delivery prediction.

## Related tools

- /word-counter/
- /text-case/
- /meta-tags/

## Sources

- [Email sender guidelines](https://support.google.com/a/answer/81126)
- [Mail User Guide](https://support.apple.com/guide/mail/welcome/mac)
- [Outlook help and learning](https://support.microsoft.com/outlook)
- [Yahoo Mail help](https://help.yahoo.com/kb/mail)

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