Split test calculator

Meet the number cruncher for subject line awesomeness

Split testing email subject lines is a key method for unlocking improved performance. While the marketing world has embraced old school A/B testing, we at Phrasee like to go all the way to “J” – that’s right, did somebody order 10 splits?

With a sufficient audience size and average open rate, testing up to 10 subject lines at once can unlock some real performance magic (how does a 15% boost in opens and clicks sound?).

What’s the best way to construct your split tests? It’s a balancing act between landing statistical confidence and maximizing ROI. The good news is, we’ve done the work for you.

Fill out the form to calculate your ideal split test distribution and get ready to test better!

Ready, set, split!

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Hi, I’m Trevor, and I’m an Analytical Linguist at Phrasee.

You may be wondering why we need your average open rate…

Well. A crucial value for this calculation is the average number of opens you get per campaign. Two different organizations might each have an audience of 1 million. But if one has an average open rate of 10% and the other 20%, they’ll have different splits. TL;DR; open rates matter to the math.