LWR Digital

Calculation Methodology

This page documents the standard mathematical formulas, fee percentages, and financial logic utilized by the calculators on LWR Digital. All calculations are executed dynamically using our verified backend logic to ensure accuracy.

1. Core E-commerce Profit Formula

All of our profit and loss tools use the standard business ledger model to determine net profit and ROI:

Gross Revenue = Item Sales Price + Shipping Charged to Customer

Total Platform Fees = Listing Fees + Transaction Fees + Processing Fees + Promoted Listing/Advertising Fees + Regulatory Operating Fees

Total Costs = Cost of Goods Sold (COGS) + Actual Shipping Cost + Transaction Fees + Miscellaneous Expenses

Net Profit = Gross Revenue - Total Platform Fees - Cost of Goods Sold - Actual Shipping Cost - Miscellaneous Expenses

Net Profit Margin = (Net Profit / Gross Revenue) * 100

Return on Investment (ROI) = (Net Profit / Total Costs) * 100

2. Platform-Specific Fee Tiers

Etsy Seller Fee Structure

Etsy fees are calculated dynamically based on regional settings:

  • Listing Fee: Flat $0.20 USD per listing (or regional equivalent: £0.16 GBP, $0.26 CAD, $0.27 AUD).
  • Transaction Fee: 6.5% of the total order value (item price + shipping + gift wrap).
  • Payment Processing Fee: Varies by country. For example, in the US it is 3% + $0.25 USD. In the UK it is 4% + £0.20 GBP + 20% VAT on the fee itself.
  • Offsite Ads Fee: 15% (for standard shops under $10k annual revenue) or 12% (for shops with $10k+ revenue) on orders driven by Google/social ads.

Amazon FBA vs FBM Structure

Amazon FBA calculations account for fulfillment and storage:

  • Referral Fee: Typically 8% to 15% depending on the product category.
  • Fulfillment Fee (FBA Only): Determined by product weight, dimension, and packaging category (standard vs oversize).
  • Monthly Storage Fee: Calculated per cubic foot based on standard off-peak (Jan-Sep) vs peak (Oct-Dec) storage rates.

eBay Fee Structure

eBay fees depend on store subscription status and category:

  • Final Value Fee (FVF): Typically 13.25% + $0.30 fixed fee per order for non-store sellers, or 12.35% for store subscribers (averages vary by category).
  • Promoted Listings: Optional ad rate percentage multiplied by the final sales price.

Shopify Transaction Tiers

Shopify fees depend on the active plan tier:

  • Basic Plan: 2.9% + $0.30 USD processing fee. 2.0% transaction fee if using external payment gateways.
  • Shopify Plan: 2.6% + $0.30 USD processing fee. 1.0% transaction fee if using external payment gateways.
  • Advanced Plan: 2.4% + $0.30 USD processing fee. 0.5% transaction fee if using external payment gateways.

Want to audit our values?

We maintain links to official documentation for all these fee rates. You can view them on our data sources list.

View Official Data Sources