Is that widget app worth it?
Every widget app is a monthly cost against an uncertain lift. This works out the lift you would need just to break even — which is usually smaller than merchants assume, and occasionally much larger.
Your numbers
Nothing is sent anywhere. The maths runs in your browser.
How to read the result
The break-even figure is the honest one. A store doing 400 orders a month at $60 with a 45% margin generates $10,800 of monthly gross profit, so a $29 app needs to lift revenue by roughly a quarter of one percent to pay for itself. At that level, arguing about the subscription is the wrong argument — the real question is whether you can attribute anything to the app at all.
The picture inverts on small stores. At 40 orders a month, the same app needs a lift ten times larger, and now the subscription genuinely matters. This is why the free tiers in the index exist and why they are a reasonable place for a new store to start.
Be honest about the lift
Vendor case studies quote uplift measured on sessions where an offer was accepted, not blended across all orders. A realistic blended AOV lift from a well-configured upsell stack is 5–15%. From a free shipping progress bar with a threshold set slightly above your current AOV, 3–8%. From a countdown timer, the effect is on conversion rate rather than order value, and it is single-digit at best on a genuinely time-limited sale.
If you enter 25% because a landing page told you to, the calculator will happily tell you the app is a bargain. It will be wrong, and so will you.
Then measure it
Model first, install second, measure third. Duplicate your theme, run the app for a full sales cycle, and compare blended AOV and conversion rate against the equivalent period — not against the app's own dashboard, which counts every accepted offer as incremental revenue whether it was or not.