Business tools that show the math.
A growing shelf of free, clear-formula calculators for freelancers and small businesses. We show the assumptions and formulas so you can verify the numbers before you act.
The Tool Shelf
Our library is structured into six practical business areas. Live tools are fully available below; planned calculators show the formulas under construction.
Invoices & payments
Manage customer accounts, overdue balances, interest charges, and payment reminders.
- Invoice Late Fee Calculator Live
- Payment Terms Generator Planned
Pricing & margins
Calculate pricing formulas, margins, markups, cost of goods, and discount impacts.
- Profit Margin Calculator Planned
- Markup & Margin Solver Planned
Cash flow
Assess break-even volumes, capital reserves, runway months, and invoice financing.
- Break-Even Calculator Planned
- Cash Flow Runway Planner Planned
Payroll & hiring
Translate annual salaries, overtime hours, contractor rates, and benefits costs.
- Employee True Cost Calculator Planned
- Contractor Rate Translator Planned
Taxes & compliance
Project sales tax checklists, compliance reminders, and self-employment tax planning notes.
- Sales Tax Estimator Planned
- Self-Employment Tax Estimator Planned
Operations
Measure meeting cost efficiencies, inventory reorder thresholds, and workspace capacities.
- Meeting Cost Calculator Planned
- Reorder Point Calculator Planned
Every tool earns its page
We believe small business tools should not be mysterious black boxes. Every calculator follows a strict quality standard.
01 Clear inputs
No guess-work. We provide plain-English guidance and default values based on common business standards.
02 Visible assumptions
Any underlying numbers—like rates, dates, or rounding rules—are written clearly next to the calculation.
03 Formula shown
We show the exact equations. You can copy the math into your own spreadsheets or explain it directly to a client.
04 Practical next steps
We generate copyable templates, email draft options, or printable summaries so you can act immediately on the result.
Need to send professional, automated invoices? Check out our payment terms guidelines to standardise your agreements and avoid past-due balances.