Zerdly

Small Business Owner Calculators

Browser-only AI and finance helpers — pressure-test an idea, draft emails, build SEO briefs and estimate AI costs.

84 tools · Top 5 most used · 100% Free

This hub pairs browser-only AI prompt helpers with the everyday finance maths a small operator actually runs — pricing a job, chasing margin, comparing a loan, or working out whether an AI workflow is worth the token spend. The tricky part is that "profit" means different things depending on where you sit: markup versus margin, gross versus net, per-unit versus per-job, and GST inclusive versus exclusive all give different numbers from the same inputs.

Pricing a product or service

Start with Markup or Margin to set a price, use the converter when a supplier quotes one and you think in the other, and add GST before it goes on the invoice; Cost Per Unit and Break-Even tell you the floor you must clear.

Markup CalculatorMarkup to Margin ConverterProfit Margin CalculatorGST Add Remove CalculatorCost Per Unit CalculatorBreak-Even CalculatorDiscount Calculator

Quoting jobs and invoicing clients

Contractors and trades: set a defensible day rate, total an invoice with tax, then check the actual profit a completed job left you after costs.

Contractor Day Rate CalculatorInvoice Total CalculatorJob Profit CalculatorGross Profit CalculatorProfit and Loss Percentage CalculatorStacked Discount Calculator

Marketing spend and customer value

Before scaling ads, check whether spend pays back — ROAS and cost per lead judge the campaign, conversion rate judges the funnel, and lifetime value tells you what a customer is worth keeping.

Return on Ad Spend CalculatorCost per Lead CalculatorConversion Rate CalculatorCustomer Lifetime Value CalculatorROI CalculatorPayback Period Calculator

AI prompts and running costs

Draft reusable prompts for emails, briefs and meetings, then estimate token spend and pick a model before you commit — the cost estimator and context planner keep an AI workflow from quietly blowing the budget.

AI Email Reply Prompt BuilderAI SEO Content Brief GeneratorAI Meeting Summary Prompt BuilderAI Token & Cost EstimatorAI Context Window & Chunk PlannerAI Model Selector HelperAI Automation Workflow Simulator

Financing, cashflow and depreciation

Compare loan offers and repayments before signing, size an emergency buffer for lean months, and spread an asset's cost with straight-line depreciation for your books.

Loan Comparison CalculatorLoan Repayment CalculatorCompound Interest CalculatorEmergency Fund CalculatorStraight-Line Depreciation CalculatorCredit Card Payoff Calculator

Common tasks

  • Set a price using markup, margin and GST
  • Quote a job and check its real profit after costs
  • Judge whether ad spend and leads are paying back
  • Estimate AI token costs before automating a workflow
  • Compare loan offers and plan repayments
  • Size an emergency fund for slow months

Top 5 Calculators for small business owners

1

AI Business Idea Prompt Builder

Business & marketing

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AI SEO Content Brief Generator

Business & marketing

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AI Email Reply Prompt Builder

Business & marketing

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AI Token & Cost Estimator

Tokens & cost

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Loan Repayment Calculator

Loans, savings and property

Use Calculator

More Useful Calculators (79)