Offer calculator

Planning a discount or promotion? The ROI & Offer Calculator shows whether the math works — what you make (or lose) on the first order, how long until a customer pays back their acquisition cost, and what they’re worth over time.

Open the dedicated Offer Calculator from the main navigation and pick a product from the search at the top, or launch it for a specific product from the Offer button on any row of the Products page.

Offer inputs

The left panel is where you model the offer — drag a slider or type a value:

• Offer price — the price you’re testing (pre-filled from the product).
• Discount — the markdown you’re considering, as a percentage.
• CAC — what you spend to acquire a new customer.
• Product cost — your cost of goods for one unit.
• Shipping cost — what it costs you to ship one order.
• Gross margin — calculated for you from price and costs, shown as a gauge.
• Repeat frequency — how many orders a customer places per year. Seeded from your store’s retention behavior, and fully editable.

Advanced options holds the rest: forecast horizon (months), payback target (months), free-shipping handling, sales channel, and any extra per-order costs (pick fees, royalties, and so on).

Auto-filled from your store

Two inputs pre-populate from your Shopify data so you don’t retype them:

• Product cost — from the variant’s “Cost per item” field in Shopify admin, if you’ve set it.
• Shipping cost — a representative rate from your default Shopify shipping profile, or the median of recent orders’ shipping amounts as a fallback.

Both are always editable — auto-fill only seeds an empty field, and anything you type sticks.

What it computes

The middle Offer Summary and the bottom metric strip translate your inputs into the numbers that matter, using your store’s actual retention curve from the last 365 days (see Cohort retention analysis):

• Average order value — the price after the discount.
• Contribution margin / order — what’s left after product and shipping costs.
• Net profit / order — contribution margin minus CAC (the first-order picture).
• Payback period — how many months until a customer’s repeat orders cover their CAC.
• Projected profit — expected profit per customer over your forecast horizon.
• Projected CLV — expected lifetime value per acquired customer.
• LTV:CAC — lifetime value relative to acquisition cost, a quick health ratio.
• Margin impact — how much the discount moves your per-order margin.
• Risk level — a fast read on whether the unit economics are healthy.

The forecast chart on the right plots cumulative profit and expected CLV per customer across their first orders, with your store’s retention curve overlaid. Toggle the cohort between Same product (repeat purchases of this SKU) and Any repeat (repeat purchases of any product) to see how each assumption changes lifetime value.

Scenarios

Found an offer worth keeping? Click Save Scenario, give it a name (for example “Summer Promo – 20% Off”), and it’s saved for your whole team. Reopen it any time from the Scenario dropdown to reload every input, or compare a few approaches by switching between them. Saving with a name that already exists updates that scenario.

Create Campaign (coming soon) will let you carry a modeled offer straight into a live campaign.

How to interpret the output

• Low risk / strong LTV:CAC — the promo pays back within your store’s typical retention window. Ship it.
• Medium risk — tight margins or slow payback. Run it as a deliberate customer-acquisition play you’re willing to absorb.
• High risk — the offer never recovers CAC. Dial the discount back, improve retention (the underlying product problem), or rethink the offer.

What it doesn’t model

• Cannibalization — promoted customers might have bought anyway at full price.
• Brand/equity effects — discounting too often trains customers to wait for sales.
• Competitor response — a deep discount on a low-differentiation product might trigger a race to the bottom.

Use the calculator for the math floor. The qualitative judgment is still yours.

Tips

• Run the numbers at multiple discount depths (10%, 20%, 30%). The payback period usually bends non-linearly; sometimes 15% is dramatically better than 20% because cost of goods eats the margin.
• Check different products. High-margin hero SKUs tolerate deeper discounts than low-margin consumables.
• Save the variants you like as scenarios so you can revisit them after a promotion and check whether the retention math still holds.

Related features

• Cohort retention analysis — the retention data the calculator reads from.
• Customer lifecycle stages — a complementary view of “who comes back.”
• Products — catalog and performance.