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Email Subject Line Tester

Analyze your subject line for length, spam triggers, personalization, and emotional appeal before you hit send.

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How to Write Email Subject Lines That Get Opened

Your email subject line is the first thing subscribers see. It determines whether your email gets opened or ignored. On average, 47% of email recipients decide to open an email based on the subject line alone.

Why Subject Lines Matter

A great subject line can increase your open rates by 50% or more. But a poor one can send your email straight to spam or the trash folder. Here's what our subject line tester analyzes:

Optimal Length (30-50 Characters)

Research shows subject lines between 30-50 characters have the highest open rates. Anything longer gets cut off on mobile devices, where over 60% of emails are read. Keep it concise while still conveying value.

Avoid Spam Triggers

Certain words and phrases trigger spam filters and reduce deliverability. Words like "free," "act now," "limited time," and "buy now" can hurt your inbox placement. Our tool checks for over 50 common spam triggers.

Use Personalization

Emails with personalized subject lines are 26% more likely to be opened. Using merge tags like the recipient's name or simple words like "your" creates a personal connection.

Strategic Emoji Use

Emojis can increase open rates by up to 56% when used appropriately. One or two relevant emojis help your email stand out in a crowded inbox. But too many look spammy.

Power Words Drive Action

Certain words trigger emotional responses and curiosity. Words like "discover," "secret," "proven," and "new" create urgency and interest that drives opens.

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