Calculation and editorial policy
How StoreCost Atlas calculates, ranks, and verifies costs.
This page defines every modeled cost layer, evidence label, ranking rule, and exclusion. The objective is a reproducible shortlist—not a promise that a public baseline will match a merchant's checkout.
01 / Formula
One comparable 12-month total.
Annual total = 12 × monthly plan + 12 × monthly apps and care + 12 × required add-on monthly cost + required one-time setup + annual card revenue × percentage fee + annual orders × fixed fee. The platform-only scope sets general apps and care to zero, but keeps add-ons required by selected must-haves in the comparison.
The selected annual-billing baseline or a merchant-entered quote.
Editable lean estimates included only in practical-stack mode.
A platform-market baseline, fallback, or confirmed provider quote.
The per-order component multiplied by 12 months of orders.
02 / Evidence
Uncertainty is a field, not a footnote.
Each cost row carries the weakest applicable evidence status. A published plan can still remain a planning baseline when the row includes estimated apps, care, converted pricing, or incomplete local payment terms.
- Official published baseline: the modeled terms are publicly documented for that market and scope.
- Planning allowance: at least one cost needs checkout or implementation confirmation.
- Payment quote required: a displayed fallback must not be treated as that provider's verified rate.
- Merchant-confirmed inputs: the user has replaced or checked the complete row against a current quote.
- A row that needs an add-on cannot be confirmed until its capability, monthly cost, and one-time setup cost are acknowledged.
- Editing a row automatically clears its confirmation.
- The tool withholds decision-ready language until all rows and selected capability requirements are verified.
03 / Ranking
Fit first when requirements are selected.
With no must-have capabilities selected, rows are ordered by modeled annual total. With requirements selected, documented fit tier is ranked first and cost breaks ties inside the same tier.
| Tier | Meaning | Required action |
|---|---|---|
| Documented fit | Current official evidence covers the selected requirement. | Confirm the exact plan, market, and implementation details. |
| Add-on / region check | An extension, integration, higher tier, or local check may be needed. | Add its quote and operational impact before comparing totals. |
| Not verified | The current evidence set does not document the capability. | Obtain written confirmation or remove the platform from the shortlist. |
04 / Scope boundary
What the model deliberately excludes.
Taxes, shipping, inventory, refunds, disputes, international-card uplifts, currency conversion, premium themes, custom development, migration, and negotiated rates are excluded unless the user adds them to a row or to the separate switching-cost input.
Open the editable calculator →05 / Review policy
How prices and claims are maintained.
Platform pricing, payment terms, capability evidence, and exchange rates are recorded with source links and dated snapshots. A material change updates the affected model, page copy, structured data, and sitemap modification date together.
- Prefer official platform pricing, support, and product documentation.
- Label converted amounts and unsupported markets instead of implying exact local terms.
- Test finite calculations, deterministic sorting, route metadata, and canonical URLs before deployment.
- Keep superseded assumptions out of decision-ready results.
07 / Apply the method
Use the baseline to ask better questions—not skip the quote.
Start with the guides, enter the store's real operating numbers, and confirm all provider rows before treating cost or payback as a purchasing recommendation.