QuickBooks Bookkeeping for Amazon FBA & Shopify | Thelonex

Free Bookkeeping Calculators | Thelonex
FREE CALCULATORS

Free Bookkeeping Calculators for
Amazon & Shopify Sellers

Quick, no-signup calculators for the numbers ecommerce sellers check most often — profit margin, sales tax, FBA fees, break-even, and more. Results update instantly, right in your browser.

Instant calculators

Pick a number to run

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Pricing

Profit Margin & Markup Calculator

Enter your cost and selling price to see your margin and markup instantly.

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Tax

Sales Tax Calculator

Work out sales tax owed and total price for any subtotal and tax rate.

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Ecommerce

Amazon FBA Fee & Profit Calculator

See your real profit per unit after Amazon's referral and fulfillment fees.

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Pricing

Break-Even Calculator

Find out how many units you need to sell each month to cover your costs.

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Tax

Payroll Tax Estimator

Estimate Social Security and Medicare withholding on any gross paycheck.

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Operations

Inventory Reorder Point Calculator

Know exactly when to reorder stock based on sales pace and lead time.

Common questions

Before you calculate

Are these calculators free to use?

Yes, completely free, no signup or email required. They run in your browser and nothing you type is saved or sent anywhere.

How accurate are the results?

They're solid estimates for planning purposes using standard formulas. Your actual numbers can vary by state, entity type, and fee structure — treat results as a starting point.

Is the Payroll Tax Estimator a full paycheck calculator?

No. It only estimates Social Security and Medicare (FICA) withholding, not federal or state income tax, which depends on each employee's W-4 and location.

Can I get help with numbers these calculators don't cover?

Yes — book a free 30-minute consultation and a QuickBooks-certified specialist can walk through your specific numbers with you.

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