Open any inbox on Black Friday morning and you'll see the same subject line written fifty different ways. "BLACK FRIDAY: UP TO 50% OFF." "Our biggest sale ever starts NOW." "Don't miss out!" Each one is trying to shout louder than the last, and together they become wallpaper.

The subject lines that get opened on Black Friday usually do one of a few things differently.

What makes a good Black Friday subject line?

A good Black Friday subject line tells the reader something specific they can't get from every other email: what's on offer, who it's for, or why it's worth opening now. It sounds like your brand, works with the preview text, and is clear before it's clever.

Six approaches that work

1. Be specific about the offer

"Up to 50% off" means very little when everyone says it. Name the thing.

• The linen sheets are finally on sale
• R200 off every pair of running shoes this weekend

2. Speak to the segment

A subject line for loyal customers can say things a subject line for your whole list can't.

• You're in first: early access starts tonight
• For the people who've bought from us before

3. Sound like you

If your brand is warm and conversational the rest of the year, it shouldn't suddenly turn into capital letters and exclamation marks. A familiar voice is a reason to open.

• We don't do this often, so here it is

4. Use the preview text

The preview text is the second half of your subject line. Use it to add the detail the subject line can't fit, not to repeat it.

• Subject: Black Friday, our way
• Preview: 15% off everything, plus free delivery until Monday

5. Make timing useful, not frantic

Urgency works when it's true and specific. "Ends at midnight" is information. "HURRY!!!" is noise.

• Last day: the sale ends at midnight

6. Try a quieter line

In an inbox full of shouting, a calm, plain subject line can stand out more than another loud one.

• A short note about this weekend

Mistakes to avoid

• All capitals and stacked exclamation marks. They read as spam to people and add risk with filters.
• Misleading lines. "Your order is waiting" when there is no order damages trust for every email that follows.
• The same subject line to everyone. Customers, new subscribers and lapsed subscribers want different things. Our guide to email segmentation strategy covers how to split them.
• Writing it last. The subject line decides whether the rest of the email gets read. Give it the time it deserves.

Test it before the big weekend

You don't need to guess on the day. Send your main Black Friday promotion to a small slice of your engaged subscribers a few days early with two different subject lines, then send the stronger one to everyone else.

In Mail Blaze, that means two small segments, one version each. Comparative filters in your campaign reports then show you which got more opens and, more importantly, more clicks, so the version that reaches most of your list is the one your audience chose. One week early is plenty.

A subject line checklist

1. Does it say something specific?
2. Does it fit the segment it's going to?
3. Does it sound like your brand?
4. Does the preview text add something new?
5. Is any urgency true?
6. Have you tested it on a small group first?

If you've already run your emails through the five questions in what makes an email relevant, the subject line is where that relevance has to show up first.

Write two subject lines for your main Black Friday send today, and test them this week. Not on Mail Blaze yet? Try it free for 14 days, no credit card needed.

Frequently asked questions

How long should a Black Friday subject line be? Short enough to read in full on a phone, usually around 30 to 50 characters. Put the most important words first.

Should I use emojis in Black Friday subject lines? One, if it fits your brand and adds meaning. Several can look cluttered in a crowded inbox.

Do urgency subject lines work on Black Friday? When the urgency is real and specific, such as an actual end time. Vague or false urgency erodes trust.

Should I send the same subject line to my whole list? It's better not to. Loyal customers, new subscribers and less engaged subscribers respond to different messages.