How to calculate email marketing ROI

Email marketing ROI answers one question: for every dollar you spend running email, how much profit do you get back? The calculation is simple; the hard part is being honest about revenue attribution and fully loaded costs.

The core formula

Use this when monthly (or campaign) costs are greater than zero:

ROI (%) = ((Email revenue − Email costs) ÷ Email costs) × 100

• Email revenue — money (or valued outcomes) attributed to email.
• Email costs — tools + labor + related spend for the same period.
• Profit — revenue minus costs (can be negative).

Step-by-step method

1. Pick a window — usually one calendar month or one campaign + 7–14 day attribution window.
2. Estimate conversions from email — clicks × conversion rate, or tracked orders tagged to the campaign.
3. Multiply by average order value (or gift size / LTV proxy) → monthly email revenue.
4. Add costs — platform fees, contractor hours, and your time at a realistic hourly rate.
5. Apply the ROI formula — and keep a note of assumptions.

Worked example

Suppose last month you sent 20,000 emails:

• Click-through rate: 2.5% → about 500 clicks
• Conversion rate on clicks: 2% → 10 conversions
• Average order value: $50 → $500 revenue
• Tools + labor: $200 costs

Profit = $500 − $200 = $300
ROI = ($300 ÷ $200) × 100 = 150%

That means you earned $1.50 profit for every $1 spent—not the same as “$36 per $1,” a commonly cited industry average that varies widely by sector.

Useful related metrics

• Revenue per subscriber — monthly email revenue ÷ active list size
• Revenue per email sent — monthly email revenue ÷ emails delivered
• Annual list value (rough) — monthly email revenue × 12

Keep a simple spreadsheet with the same inputs (revenue, costs, attribution window) so you can compare months without changing the formula.

What this estimate is not

ROI math is an illustrative estimate, not a forecast or guarantee. Attribution, seasonality, deliverability, and offer quality all move the number. For engagement metrics beyond opens, see newsletter analytics beyond open rate.

FAQ

What is the email marketing ROI formula?

ROI (%) = ((Email revenue − Email costs) ÷ Email costs) × 100 when costs are greater than zero.

What counts as email revenue?

Attributed purchases, donations, signups with a dollar value, or other conversions you can reasonably tie to email clicks or campaign windows.

What costs should I include?

ESP or platform fees, creative/labor time, list acquisition (if paid), and any paid tools used primarily for email.

Is $36 return per $1 spent a guarantee?

No. Industry averages are directional only. Your ROI depends on list quality, offer, deliverability, and attribution method.