Flash sale: when it pays, and what it teaches your list
A discount with a short fuse. It brings a rush of orders, and it teaches everyone watching that waiting gets rewarded. Plan for both before you send the first email.
- 043Flash Sale
- A discount or promotion offered for a very short period to create urgency and drive quick sales.
- Usually runs
- A day or two, sometimes only a few hours
- Good for
- Clearing stock, a genuine occasion, a thank-you to your regulars
- Costs you
- Margin on orders that would have come anyway
- Judge it on
- Margin across the sale and the weeks after it
What the spike on sale day is made of
A flash sale works, in the sense that the revenue line jumps. The useful question is what's inside the jump. Some of it is new customers. Some is stock you were glad to move. And some is your regulars buying what they'd have bought next week anyway, at a lower margin.
That last slice is why a flash sale needs a reason. End-of-line stock, a real occasion, a thank-you to people who've stuck with you. A quiet month isn't one. It's usually an attention problem, and a code doesn't fix attention. There are better levers than a discount for that.
The emails a flash sale needs, and who gets each one
| Send | Who gets it | Its job |
|---|---|---|
| Early access | Your best customers, a few hours ahead | First pick, so your regulars feel it first |
| The announcement | Engaged subscribers, everyone only if it's site-wide | What's on, how much, and the exact end time |
| The reminder | People who clicked and didn't buy | The products they looked at, not the whole sale |
| Last call | Clickers, and anyone with a cart open | The real deadline, said once |
Leave out anyone who paid full price in the last couple of weeks. They'll see the sale anyway, and nobody enjoys finding out they paid more last Tuesday.
Make the deadline real, or leave it out
A countdown that resets, or a last chance that comes back next week, works once. After that your list stops believing any deadline you set, including the honest ones.
It's a legal problem too. Falsely claiming an offer is only available for a limited time, to rush somebody's decision, is on the list of practices the Digital Markets, Competition and Consumers Act bans outright. End the sale when you said you would, put the prices back, and don't extend it by popular demand.
Judge a flash sale a month later, on margin
Sale-day revenue is the least useful number you'll get. Compare margin across the sale and the weeks after it with a normal stretch, because orders pulled forward show up later as a dip. Then check how many sale buyers came back at full price.
Count this year's sales too. If revenue bunches around code days and goes quiet in between, the list has learned your calendar. Tag discounted orders so your post-purchase emails can treat bargain hunters differently from full-price buyers.
Related terms
FAQs
How long should a flash sale last?
Long enough for your list to see it, short enough that the deadline means something. Plenty of people only check email in the evening, so a sale that's over by lunchtime misses them. A day or two gives most people a fair chance. Whatever you pick, say the end time plainly and stick to it.
How often can we run a flash sale before customers wait for the next one?
There's no safe number, but there's a clear sign. If revenue bunches around code days and goes flat in between, and your best-opened emails are the ones hinting at an offer, customers have learned to wait. A few sales a year with real reasons behind them is a different thing from a sale whenever the month looks soft.
Should our best customers get the flash sale discount?
Give them first access, not a bigger discount. A few hours' head start on the same offer makes them feel noticed and costs you nothing extra. Handing your regulars deeper codes than everyone else teaches the people who'd buy anyway to hold out for one.
Rather we explained it on your own account?
Bring your Klaviyo account to a growth consultation. We'll walk through what this means for your numbers, in plain English, and what we'd fix first.
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