How to Measure Email Marketing ROI

Most email platforms report opens and clicks but struggle with revenue attribution. Revenue can arrive days or weeks after an email is sent, via multiple devices, or after the customer saw other touchpoints first. Without a clear methodology, you'll either over-credit or under-credit email.

AskBiz unifies email platform data (Klaviyo, Mailchimp, Campaign Monitor) with your Shopify or WooCommerce orders to give you a single, accurate revenue figure per campaign.

The attribution window is the number of days after an email open or click during which a purchase is credited to that email. Common settings:

• 1-day click — very conservative; only credits fast, intent-driven purchases
• 7-day click / 1-day open — Klaviyo default; good balance for most e-commerce
• 30-day click — common for high-consideration purchases

Consistency matters more than the exact window. Pick one and stick to it so you can compare campaigns over time. Change the default in Settings → Attribution.

Campaign revenue = orders placed within the attribution window by recipients who opened or clicked the email.

AskBiz shows this automatically in the Campaigns dashboard. To calculate manually:

1. Export orders tagged with a UTM campaign parameter matching your email

2. Add orders from your ESP's attributed revenue report

3. Deduplicate any order that appears in both sources

Pro tip: use consistent UTM parameters on every email link — utm_source=email&utm_medium=campaign&utm_campaign= — so web analytics and your ESP agree.

Email programme costs include:

| Cost item | Notes |

|-----------|-------|

| ESP platform fee | Monthly/annual subscription |

| Agency or copywriter fees | If outsourced |

| Designer time | Estimated hourly rate × hours |

| Promotions or discounts | Value of discount codes used |

| Fulfilment uplift | Extra orders require extra fulfilment |

For a quick ROI calculation, most businesses use only the ESP fee plus any direct creative costs.

Email ROI = (Revenue − Costs) ÷ Costs × 100

Example:

• Monthly email revenue: £18,000
• Monthly costs: £600 (ESP £200 + agency £400)
• ROI = (18,000 − 600) ÷ 600 × 100 = 2,900%

Industry benchmarks vary widely. A well-managed e-commerce email programme typically achieves 3,000–4,200% ROI. B2B and lead-gen programmes are usually lower (500–1,500%).

In AskBiz, view Email → ROI Overview for your live figure.

ROI is useful for budget discussions, but revenue per email is the most actionable day-to-day metric:

RPE = Campaign revenue ÷ Emails delivered

A good benchmark for e-commerce: £0.08–£0.15 per email sent. Highly segmented lists can reach £0.40+.

Track RPE trend over time — a declining RPE signals list fatigue, deliverability degradation, or offer fatigue, even if absolute revenue is growing because your list is growing.

Double-counting with paid social: if a customer clicked a Facebook ad and then opened an email before purchasing, both channels may claim the revenue. Use a last-click or data-driven model to resolve this.

Ignoring unsubscribes: aggressive sending may boost short-term revenue but erodes list value. Track revenue per subscriber per month alongside ROI to catch this.

Not separating flows from campaigns: automated flows (welcome series, abandoned cart) usually have 5–10× higher RPE than broadcast campaigns. Keep them separate in your reporting so you know where to invest.