What makes a good email subject line for an ecommerce brand?

Why test subject lines on clicks, not opens?

Because opens barely respond to subject lines any more, and clicks do. For a brand bringing existing customers back for another order, the subject line is worth judging on the number that leads to that order. In Everboost’s 2026 ecommerce email panel, no subject line feature, not length, not emojis, not questions, not offers, moved recorded open rates by more than about 3%. Apple Mail Privacy Protection can record opens automatically when an email arrives, which flattens the differences.

Clicks and revenue did differ, by around 9% to 13% on the features that held across most brands. That is where subject lines still earn or lose money, and it is what every finding below measures.

What did the data show?

The analysis covers 8,750 email campaigns from Everboost’s 2026 ecommerce email panel: 37 direct-to-consumer brands whose Klaviyo accounts we have worked in or audited, including campaigns sent before or without our involvement, analysed together with no brand identified. They span health and wellness, personal care, pet and other categories, and the campaigns were sent between 1 November 2025 and 31 October 2026 to at least 500 people each, excluding resends. Each campaign was indexed against its own brand’s median, so the table compares brands with themselves: +9% means 9% better than that brand’s typical campaign.

Subject line feature	Campaigns	Clicks vs brand’s other campaigns	Revenue per email	Brands where clicks were higher
Names an offer (% off, sale, free, save)	1,876	+9%	+5%	23 of 32
Contains a specific number (ignoring personalisation tags)	2,376	+9%	+4%	25 of 36
30 characters or fewer	3,045	+3%	+3%	20 of 35
Urgency words (last chance, ends, final)	844	+1%	+11%	16 of 28
Emoji	2,588	+1%	+1%	18 of 32
Uses “you” or “your”	2,531	-1%	0%	15 of 33
Written as a question	1,022	-12%	-13%	7 of 32

As of November 2026, these are all the campaigns that met the criteria. This is an observational analysis of real campaigns, not a controlled test: features overlap, and offers in particular often come with numbers and capital letters, so read each row as a pattern worth testing rather than a guaranteed effect. Revenue per email is Klaviyo-attributed, which is useful for comparing campaigns within a brand but overstates what any one email caused.

Do questions work in subject lines?

Mostly not. This was the clearest pattern in Everboost’s data: subject lines written as questions had about 12% fewer clicks and 13% less revenue per email, and did worse in 25 of the 32 brands that used them often enough to compare. The gap held among campaigns with no offer too, at about 10% fewer clicks, so it is not just that questions were used for weaker campaigns.

Our read is that in ecommerce the reader decides in a second whether there is something in it for them, and a question makes them do the work. Worth testing: answer the question instead, so “Looking for a new evening routine?” becomes “The evening routine 4,000 customers reorder”, using a real number from your own order data.

Do numbers and offers increase clicks?

In this data, yes, modestly. Lines that named an offer had about 9% more clicks than the same brand’s typical campaign, in 23 of 32 brands. Campaigns with a specific number also had about 9% more, in 25 of 36, but three in four offer lines contain a number, so the two overlap. Taking offers out, lines with a number still had about 10% more clicks, though in a smaller majority of brands, 17 of 29. Subject lines with a fully capitalised word such as NEW or SALE also did better; about half of them appear in offer campaigns, and we have not separated that from other launch and sale effects, so treat it as a lead to test.

Numbers make a claim concrete: “3 ways”, “20% off” or “48 hours” tells the reader exactly what they get. Offers come with a cost the click rate does not show, because a brand that leads every subject line with a discount teaches its customers to wait for one. The habit Everboost recommends is to keep offer-led subject lines for real offers and test numbers from reviews, order data and product facts the rest of the time.

Do emojis help email subject lines?

Not in this data. Across 2,588 campaigns with an emoji in the subject line, clicks and revenue were about the same as the same brands’ campaigns without one, and the emoji campaigns did better in 18 of 32 brands, close to a coin toss. In Everboost’s view emojis are a brand voice choice, not a performance lever, so use them if they suit your brand and stop testing them.

Does subject line length matter?

Hardly at all. Subject lines of 30 characters or fewer had about 3% more clicks and 3% more revenue per email, and did better in 20 of 35 brands, close to a coin toss. What matters more is where the important words sit. Phone inboxes cut subject lines off at different points: in one device test the Gmail app showed about 33 to 37 characters and Apple Mail on iPhone about 48. Everboost’s advice is to put the product, number or offer in the first 30 or so characters.

Do urgency words work?

Not as a general boost. Words such as last chance, ends tonight and final hours made almost no difference to clicks across the panel and helped in 16 of the 28 brands that used them, though revenue per email was about 11% higher, probably because urgency words mostly appear on the last day of real sales. Urgency works when the deadline is real and the reader already wants the thing; added to an ordinary campaign it reads as noise. Everboost’s advice is to save it for the last day of a genuine sale.

What are good ecommerce subject line examples?

These 40 examples apply the patterns above, the standard Everboost writes to: specific, statement-led, and offer-led only when there is an offer. Swap in your own products, and only use numbers you can back up from your own reviews, orders or product facts. For supplements and skincare, keep health claims out of subject lines entirely; they need the same substantiation as anywhere else.

Welcome

1. Your 15% off is inside, plus how to choose
2. Welcome. Here’s what 3,000 customers buy first
3. Start here: the 2-minute routine
4. The 3 things to know before your first order
5. Your code expires in 48 hours

Abandoned cart and checkout 6. Your Daily Greens is still in your basket 7. 4.8 stars from 2,000 reviews, and your basket’s saved 8. We saved your basket 9. Free delivery on your basket ends tonight 10. The 3 things people check before buying this

Launch 11. NEW: the vanilla protein you asked for 12. Out now: magnesium in a gummy 13. 3 days early access, just for subscribers 14. It’s here, and it’s 20% off until Sunday 15. The formula we spent 18 months on

Back in stock 16. Back in stock: the night serum 17. It’s back (and it sold out in 6 days last time) 18. Restocked: your favourite, in 2 sizes 19. Back today, limited batch

Sale 20. 25% off everything until midnight 21. SALE: up to 30% off bundles 22. Last day: 20% off ends at midnight 23. Our Black Friday offer starts now 24. 2 for 1 on the bestsellers, 48 hours only

Post-purchase and education 25. Your first 30 days: how to fit it into your routine 26. Your order is on its way, here’s how to use it 27. 3 mistakes people make in week one 28. Your first 8 weeks: how to build the habit 29. The 60-second routine, step by step

Replenishment and subscription 30. Reorder in one click before you run out 31. Your 30-day supply is nearly gone 32. Save 15% on every order with a subscription 33. Skip, pause or swap any time 34. Never run out: 3 reasons customers subscribe

Win-back 35. It’s been 90 days. Here’s what’s new 36. What’s new since your last order 37. We changed the formula. Here’s how (only if you did) 38. 3 new products since your last order 39. Your favourite, now in a bigger size 40. One last thing before we stop emailing

How should you test subject lines?

Test one change at a time, on clicks or revenue, over more than one campaign:

1. Pick one variable, such as question versus statement, or number versus no number.
2. Split the send randomly and make sure each half is large enough to show a difference; a few hundred recipients per version will not.
3. Choose the winner on clicks or placed orders. In Klaviyo, set the A/B test’s winning metric to click rate or placed order rate. Klaviyo suggests open rate for subject line tests, but Apple Mail Privacy Protection inflates opens, so clicks and orders are the safer judge.
4. Repeat the test on two or three more campaigns before you treat the result as a rule.

Everboost treats a single A/B result as a lead, not a rule, until it repeats. For when to send, see our send-time analysis. To see what better campaign and customer decisions did for one brand, read the Salt Grooming case study, where returning customer sales grew 58% in 12 months. If you would like a retention agency to review your subject lines and campaigns against this data, book an intro call.