Tools

Free financial models, profit estimators, and fee calculators designed by Carinex Tech to help online sellers optimize unit economics.

Free interactive financial models, fee estimators, and profit calculators designed by Carinex Tech to help e-commerce brands, sellers, and creators protect their net margins.

Payment Processing

PayPal Fee Calculator

Calculate domestic vs international PayPal merchant fees, cross-border conversion spreads, and exact invoice amounts to receive target net payouts.

Payment Processing

Stripe Fee Calculator

Accurate breakdown of standard credit card processing, international interchange fees, currency conversion, and net bank deposits.

E-Commerce Platforms

Shopify Fee & Profit Calculator

Calculate total monthly Shopify costs across Basic, Shopify, and Advanced plans. Find out exactly when upgrading plans saves you money.

E-Commerce & TikTok

TikTok Shop Profit Calculator

Calculate real take-home net profit per unit in US, UK, and EU after referral fees, creator affiliate commission, VAT/taxes, shipping, and return loss.

Paid Advertising

TikTok Ad ROAS & Break-Even Calculator

Find your exact target break-even return on ad spend (ROAS) and maximum allowable CPA on TikTok Shop ads before burning marketing budget.

Platform Economics

Shopify vs TikTok Shop Comparison

Compare platform commission rates, payment processing fees, and see exactly how much revenue you retain annually with an independent storefront.

Pricing Strategy

Profit Margin & Markup Calculator

Quickly convert wholesale supplier costs into target retail prices and calculate gross margin percentages and markups for any physical product.