Klaviyo Replenishment Flow: Time Refills From Order Data
The label says 30 servings. Your customers say 34 days. Build the Klaviyo replenishment flow from the reorder interval hiding in your own orders, and land the reminder a few days before the tub runs empty.
Most replenishment flows are timed by the label on the jar.
Thirty servings, so the reminder goes out at day 30. It feels logical. And it's wrong for almost every store I've looked at, because customers skip days, share the tub with a partner, or double up on a hard week.
Here's the short answer. A Klaviyo replenishment flow should fire a few days before the customer runs out, and the only honest source for "runs out" is your own order data. Pull every customer who bought the product twice, find the median number of days between those two orders, subtract your shipping time and a small buffer, and use that number as the first time delay. One flow per product, triggered by Placed Order, filtered to that product. That's the whole idea. The rest of this post is how to do it in an afternoon.
Why does a guessed interval break your replenishment email?
Because a reorder reminder email has one job: arrive at the exact moment the customer notices the tub is getting light.
Too early, and it reads like a pushy ad. They still have two weeks of product, so they archive it. Too late, and they already bought a replacement at the pharmacy, or they quietly went without and broke the habit. Either way the email you paid to build sent nobody back.
Klaviyo's own guide to creating a replenishment flow says to set the timing of the first reminder from your customers' established buying cycles, found by reviewing your existing purchase data. Its example is a supplement with a 30-day supply and a first reminder about 25 days after the order.
That's a good default. But the label is a guess about how people use the product. Your orders are the record of how they actually did.
The label tells you how long the product should last. Your order history tells you how long it did. Time the email to the second number.
How do you find a product's real reorder interval?
Here's the method. Five steps, no app required.
- Export your Shopify orders for the last 12 months.
- Keep only orders containing the product, grouped by customer email.
- Keep customers who bought it at least twice.
- Measure the days between each customer's first and second order.
- Take the median of those gaps.
Use the median, not the average. A handful of customers who reorder after 120 days will drag an average out by a week and make your email late for everyone else.
This is where AI earns its seat. Paste the export into an AI assistant and ask it to group orders by email, filter to the product name, and return the median gap between first and second purchase plus how the gaps spread out. What used to be an hour of spreadsheet formulas becomes a two-minute question, and you can repeat it for every product in your catalog the same afternoon.
Run the math on a store like this (a hypothetical): a magnesium sleep drink sold in a 30-serving tub. Over 12 months, 412 customers bought it at least twice. Here's how their gaps spread out.
412 repeat customers. Median gap: 34 days. Illustrative data, not a benchmark.
The label says 30. The median customer reorders around day 34. A flow timed to the label would land roughly four days early for half the buyers, and 96 + 38 = 134 people already reordered before day 29 without any reminder at all.
When should the reorder reminder email actually send?
Not on the day they run out. A few days before.
The customer needs time to open the email, order, and receive the box before the last scoop. So work backward from the median.
| Input (hypothetical tub) | Days |
|---|---|
| Median gap between first and second order | 34 |
| Minus shipping time to most customers | 4 |
| Minus buffer so they never hit empty | 3 |
| First reminder sends on | day 27 |
| Second reminder (if no reorder) | day 34 |
| Last follow-up, then hand off to winback | day 41 |
Here's the math: 34 minus 4 minus 3 is 27. If they order on day 27, the box lands around day 31, three days before the median customer would have run out. That's the window you're aiming at.
Two adjustments I'd make on a live store. If your gaps are spread wide (lots of bars on both sides), set the first email nearer the earlier end, because a slightly early reminder costs you less than a late one. And if the product comes in two sizes, run the numbers separately. A 60-serving tub has its own interval, so it gets its own flow.
How do you build the Klaviyo replenishment flow, step by step?
Klaviyo has prebuilt replenishment templates in the flows library for Shopify stores (search "replenishment" under Encourage repeat purchases). Start there or start blank. Either way, the guts look like this:
- Trigger: Placed Order, with a trigger filter of Items contains the product name, so only orders containing that product start the flow.
- Profile filter: Placed Order zero times since starting this flow, limited to that same product. Klaviyo warns that without the product limit, a purchase of something unrelated could stop the reminder.
- Time delay: your number from the table above, not a template default.
- Email 1: a plain reminder that names the product, shows how many days they've had it, and links straight to the product page.
- Email 2: the same product plus one related item (a second flavor, a travel size).
- Follow-up: the last touch, which is where a small incentive goes if you use one at all.
Klaviyo's rule of thumb is two reminders and one follow-up, with a note not to badger customers. I agree with both halves. Anyone still quiet after the follow-up belongs in your Klaviyo winback flow, timed off the same data.
One more split worth adding. A Klaviyo community thread on first-time versus repeat buyers suggests a conditional split on whether someone has ever received this flow before. First-timers get a warmer email that teaches the routine. Your 4th-time reorderers get a two-line reminder. Same consumable reorder flow, two tones.
A first-time buyer needs a reason to reorder. A loyal buyer needs a shortcut. Give each one the email they need.
Can Klaviyo's predictive analytics time the refill for you?
Partly. Klaviyo's predictive analytics gives every profile that has ordered an expected date of next order, and you can trigger a flow from it. The model is retrained at least once a week. To qualify, Klaviyo says you need at least 500 customers who placed an order, at least 180 days of order history, orders in the last 30 days, and some customers with 3 or more orders.
But here's the thing. Klaviyo states that the expected date doesn't consider which products someone bought, and it recommends regular replenishment flows when you know a product's cycle. It also warns that counting down to that date for repeat buyers can drive up unsubscribes, because they get the same sequence before every order. For one-time buyers it estimates the date from all your customers' behavior, which tells you nothing about the tub they're holding.
So my take: product-level data for products with a clear cycle, expected date of next order as a backup for mixed carts and catalogs too small to slice. The AI prediction is useful. Your own order history for a specific product is more useful.
Where does the replenishment email send people?
This is the part almost every guide skips.
The email does its job when the click happens. After that, your product page does the selling. And a returning customer who lands on a page that buries the subscribe option, hides the bigger size, or makes them hunt for the add-to-cart button is a reorder you paid for and lost.
The math on our homepage shows what's at stake per click. A page converting 1% of visitors at a $50 average order value earns $0.50 per visitor. A page converting 3% at an $80 average order value earns $2.40 per visitor. That's 4.8 times more revenue per visitor from the same traffic. Send 300 replenishment clicks to the first page and you bank $150. Send them to the second and you bank $720. Same emails. Same customers.
That's why I'd spend as much time on the reorder destination as on the flow. A product page built for returning customers and the playbook for consumable product pages cover what to put above the fold: the size step-up, the subscribe-and-save choice, and one line about why the routine works. A replenishment flow sending clicks to a weak page is a leaking bucket on a timer.
What to do next
Pick your best-selling consumable. Export the orders tonight, find the median gap between first and second purchase, and compare it with the delay your replenishment flow uses right now. If the two numbers are more than 3 days apart, change the delay and leave everything else alone for 30 days. Then check reorders and see what the timing alone was worth. For the rest of your flow setup, the Klaviyo flows for Shopify guide and the post-purchase flow examples fill in the emails that come before this one.
Book Your Profit Audit
A perfectly timed replenishment email still hands the sale to your product page, and that page decides whether the reorder happens or the customer drifts to the pharmacy shelf. Get your free profit audit and we'll show you what each returning click is worth right now, then rebuild a high-converting product sales page in less than 15 minutes.
Or go here to check it out → revenueflows.ai
P.S. The label guesses when the tub runs out. Your orders already know. Time the email to the data and send the click to a page that closes.
Frequently asked questions
When should a Klaviyo replenishment flow send the first email?
A few days before the customer actually runs out, which you find in your own order data. Take the median days between a customer's first and second order of that product, subtract your shipping time and a 3 day buffer, and use that as the first time delay. Klaviyo's own example sends at day 25 for a 30-day supply.
What trigger should a Klaviyo replenishment flow use?
Klaviyo's help center recommends the Placed Order metric, with a trigger filter like Items contains the product name, so only orders with that product start the flow. Add a profile filter of Placed Order zero times since starting this flow, limited to that product, so people who already reordered stop getting reminders.
Can I use Klaviyo's Expected Date of Next Order for replenishment?
You can trigger a flow from it if your account qualifies for predictive analytics, which needs at least 500 customers with orders, 180 days of order history and orders in the last 30 days. But Klaviyo says the date ignores which products someone bought, so use product-based replenishment flows when you know a product's cycle.
How many emails should a replenishment flow have?
Klaviyo's guide gives a rule of thumb of two reminder emails and one follow-up after the projected buying cycle. I keep it to that and hand anyone who still hasn't reordered to the winback flow instead of a fourth reminder.
Should a replenishment email include a discount?
Not in the first email. A buyer who is about to run out of something they like doesn't need a coupon to reorder, they need a reminder and a one-click path back. Klaviyo suggests an incentive in the follow-up, so if you use one, put it there.