How to Measure Email ROI

Start with cost, because it’s the easy half

Your email cost is more than your ESP bill. Add up sending platform costs, the time your team spends designing and writing campaigns, and any contractor or agency spend. For a small team sending a few campaigns a month, this is usually a few hundred to a few thousand dollars — small enough that even modest attributable revenue clears the bar.

Attribution: connect a send to a dollar

The revenue side requires actual plumbing. At minimum, you need three things wired together: a unique identifier per contact, event tracking on your product or storefront, and a way to join "received campaign X" to "completed action Y" within some attribution window.

• Tag outbound links with UTM parameters that map back to the campaign and even the specific automation step.
• Fire a webhook or API event when a contact converts, and store the campaign/automation ID that touched them last.
• Pick an attribution window (7–14 days is reasonable for most B2B and SaaS products) and stick to it consistently.
• For multi-touch journeys, decide up front whether you’re doing last-touch, first-touch, or a simple linear split — and disclose which one you’re using when you report results.

The metrics worth tracking beyond opens

Open rate is a proxy, and an increasingly unreliable one thanks to Apple Mail Privacy Protection and similar features that pre-fetch images regardless of whether a human opened the email. Click-through rate is a better proxy for engagement, but still not revenue.

For a transactional-and-marketing platform like MailCraft, the metrics that map most directly to ROI are: conversion rate per campaign (contacts who completed your target action / contacts who received the send), revenue per email, and cost per acquisition when email is the last touch before signup or purchase.

A simple monthly ROI review

You don't need a data warehouse to do this well. A monthly review that pulls campaign-level sends, opens, clicks, and attributed conversions into one sheet — alongside your all-in cost for the month — is enough to catch campaigns that are quietly losing money and double down on the ones that aren't.

If a welcome sequence converts trial signups to paid at 4% and a cold-list campaign converts at 0.1%, that's not a subtle signal. Kill the second one and reinvest the time in the first.

Where MailCraft fits

Because MailCraft keeps transactional and marketing email on the same contact record, you can see the full picture: a contact’s signup confirmation, their onboarding drip, and the campaign that eventually converted them, all sent to the same contact instead of scattered across two tools. Webhooks fire for sends, opens and clicks, so feeding the attribution pipeline above is a matter of a few API calls rather than a data engineering project.