Free Seller Bookkeeping Calculators & Tools - Calculate Profit, Tax, COGS
Seller Bookkeeping

Free Seller Bookkeeping Calculators

Powerful tools to calculate profit, taxes, COGS, and more

Optimize Your Business with Our Free Tools

Make better business decisions with accurate calculations. Our free calculators help you understand profitability, tax obligations, break-even points, and more. No signup required—just enter your numbers and get instant results.

Why these calculators matter: Most sellers rely on guesswork about profit margins and pricing. These tools give you accurate data to price competitively, identify your best products, and plan for taxes.

Essential Business Calculators

COGS Calculator

Calculate the true cost of each product including materials, shipping, packaging, and labor.

  • Material costs
  • Shipping to warehouse
  • Packaging per unit
  • Labor allocation
Open COGS Calculator

Profit Calculator

Determine your net profit after all expenses including fees and marketplace charges.

  • Sale price input
  • COGS deduction
  • Fee calculation
  • Net profit result
Open Profit Calculator

Tax Calculator

Estimate quarterly taxes and self-employment tax obligations.

  • Income estimation
  • Self-employment tax
  • Quarterly payments
  • Annual liability
Open Tax Calculator

Margin Calculator

Calculate gross margin, net margin, and markup percentages instantly.

  • Gross profit margin
  • Net profit margin
  • Markup percentage
  • Pricing analysis
Open Margin Calculator

Break-Even Calculator

Find exactly how many units you need to sell to break even.

  • Fixed costs
  • Variable costs per unit
  • Price per unit
  • Break-even quantity
Open Break-Even Calculator

ROI Calculator

Measure return on investment for marketing campaigns and business decisions.

  • Campaign investment
  • Revenue generated
  • ROI percentage
  • Payback period
Open ROI Calculator

Marketplace-Specific Calculators

Amazon FBA Calculator

Calculate FBA fulfillment fees, storage costs, and net profit per unit.

  • FBA fulfillment fees
  • Storage fees
  • Referral percentage
  • Net profit per unit
Open FBA Calculator

Sales Tax Calculator

Calculate sales tax by state and understand your tax obligations.

  • State selection
  • Local tax rates
  • Tax amount due
  • Annual projections
Open Sales Tax Calculator

Fee Comparison Tool

Compare fees across different marketplaces to find the best channel.

  • Amazon vs Shopify
  • eBay vs Etsy
  • Walmart fees
  • Net profit comparison
View All Calculators

How to Use These Calculators

Get the most accurate results with these tips

Best Practices

For COGS Calculator

  • Include ALL production costs
  • Add inbound shipping to warehouse
  • Include packaging per unit
  • Account for quality control waste

For Profit Calculator

  • Enter exact marketplace fees
  • Include payment processing fees
  • Factor in refunds/chargebacks
  • Don't forget shipping supplies

For Tax Calculator

  • Use net profit (after expenses)
  • Account for quarterly variation
  • Consider state taxes
  • Consult a tax professional

Calculator & Tools Facts

87%

Of sellers underprice due to incomplete cost analysis

3x

More profitable when using data-driven pricing

$5,000

Average annual savings from accurate tax planning

10 min

Time to calculate profitability per product

42%

Average margin improvement with optimization

100%

Accuracy when all costs are properly included

Calculator FAQ

Are these calculators really free?

Yes, completely free! No signup, no email required, no hidden costs. We believe every seller should have access to accurate financial tools. Use them as many times as you want.

How accurate are the calculators?

The calculators are as accurate as the data you input. They use standard accounting formulas used by professional accountants. If you enter correct numbers, you get correct results. Garbage in = garbage out, so verify your input data.

Do I need to save my calculations?

The calculators don't save data automatically (privacy-first design). We recommend screenshotting your results or copying them to a spreadsheet for your records. For ongoing tracking, use our Excel templates or accounting software.

Which calculator should I use first?

Start with the COGS Calculator to understand your true product costs. Then use the Profit Calculator to see what you're actually making after all fees. Finally, use the Tax Calculator to understand your tax obligations. These three give you the complete financial picture.

Can I use these results for my taxes?

The Tax Calculator gives you estimates for planning purposes only. For actual tax filing, consult a professional tax accountant. However, the calculations are based on IRS formulas, so they're solid for planning and setting aside money quarterly.

How often are calculators updated?

We update calculators when marketplace fees, tax rates, or formulas change. Follow our updates or bookmark this page to always have the latest versions. Most updates are minor adjustments to fee percentages.

What if I don't know my exact COGS?

Start with a rough estimate based on what you paid for inventory. Include wholesale cost, shipping to warehouse, packaging. As you track your actual costs over time, refine these numbers. Even a rough COGS is better than guessing—it tells you if a product is worth selling.

Can I use these for multiple marketplaces?

Absolutely! The basic calculators (COGS, Profit, Margin) work for any marketplace. Just input the specific fees for each platform. We also provide platform-specific calculators for Amazon FBA and Sales Tax that account for those unique fee structures.