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Free tools to grow and optimize your email marketing
Simple, accurate calculators and builders for small businesses, freelancers and newsletter creators. Everything runs in your browser — we never see what you type.
Popular tools
Pick one and get an answer in under a minute.
- Email Marketing ROI Calculator
Estimate revenue, profit, ROI and the break-even point for any campaign.
- Email Subject Line Preview
See roughly where phones and desktop inboxes cut off your subject and preview text.
- Newsletter UTM Builder
Build clean, correctly encoded tracking links — one at a time or a whole newsletter at once.
- Email List Growth Calculator
Simulate subscriber growth from signups and unsubscribe rate.
- Email Open Rate Calculator
Calculate open rate and learn why opens are an imperfect signal.
Why use these tools
Your data stays with you
Calculations happen on your device. No accounts, no forms sent to a server.
Formulas you can check
Every tool explains its math and its assumptions, so you know what the numbers mean.
Built for real campaigns
Handles the edge cases — zero costs, existing URL parameters, emoji in subject lines.