# Margin calculation framework · Rodan Practice
Ecommerce margin calculation framework for gateway diagnostics: how Rodan structures contribution, leakage and pricing analysis in practice.
RODAN-285 · Ecommerce gateway

# Blended margin calculation framework

   Methodology for free Shopify audits and paid deep-dives. Goal: one blended margin view across channels that finance and growth can both defend.

## Definitions

- **Product margin** = Net sales − COGS (landed where available)

- **Contribution margin** = Product margin − variable selling costs (ads, payment fees, shipping subsidies, returns variable cost)

- **Blended channel margin** = Contribution margin aggregated across Shopify + marketplaces + wholesale, with channel fees allocated

## Required inputs

- Order lines with SKU, quantity, net revenue, discounts, taxes, refunds

- COGS or unit cost table (and currency)

- Channel / source attribution (Shopify, Amazon, wholesale, etc.)

- Ad spend by channel and period

- Payment processing fees (or % assumption)

- Shipping revenue vs shipping cost

- Returns / refunds timing

## Free audit checks (3–5 findings)

- Missing or stale COGS on active SKUs

- Refunds and discounts not netted consistently

- Ad spend not joinable to order periods

- Marketplace fees invisible in Shopify-only views

- Bundle / subscription SKUs breaking unit economics

## Paid deep-dive additions

- Full blended margin by channel and cohort

- SKU / collection contribution waterfall

- Leakage map with quantified £ impact ranges

- Costed proposal for Quantsole dashboard + data plumbing

## Pricing

- **Free audit** - short Shopify margin plumbing check, 3–5 findings by email

- **£1k light** - paid deep-dive on blended margin for one primary channel stack

- **£2k full** - multi-channel leakage map, contribution waterfall, costed Quantsole / BI append

## Paid deep-dive report + proposal append

- Scope and data used

- Blended margin view (channel / cohort)

- Ranked leakage findings with £ ranges

- What was not verified

- **Proposal append** - recommended dashboard / plumbing package, indicative fee band, 30/60/90 sequencing

## Sales brief (one page)

   **Opener:** Tariff and channel mix just moved your US or marketplace margins, and Shopify alone cannot show where contribution is leaking.

   **Offer:** Free margin plumbing audit (3–5 findings), then optional £1k light or £2k full blended-margin diagnostic with a costed next-step append.

   **Buyer:** DTC founder or ecommerce director at roughly £2–20m brands.

   **Public entry:** [Margin leakage calculator](/tools/margin-leakage) · intake [tally.so/r/jaYOaJ](https://tally.so/r/jaYOaJ) · [ecommerce page](/for/ecommerce)

   **Next step:** request free audit · hello@rodan.io

   Intake form: [tally.so/r/jaYOaJ](https://tally.so/r/jaYOaJ)

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