Free Tools & Calculators
Fast, focused calculators for the numbers that go on your invoice — no signup, no ads blocking the tool.
Invoice Number Generator
Create unique, sequential invoice numbers.
Sales Tax Calculator
Add tax, or back it out of a tax-inclusive price.
Discount Calculator
Percentage or flat discounts, and the final price.
Late Fee / Interest Calculator
Interest owed on an overdue invoice.
Hourly Rate Invoice Calculator
Hours × rate plus expenses.
Currency Converter
Convert invoice amounts at your agreed rate.
When To Use
Which calculator do you need?
- Starting your invoicing system? Use the invoice number generator to set up a clean numbering sequence.
- Selling taxable goods or services? The sales tax calculator adds tax or extracts it from a tax-inclusive total.
- Offering a deal? The discount calculator shows the final price after percentage or fixed discounts.
- Client paying late? The late fee calculator works out interest by the day.
- Billing by the hour? The hourly rate calculator totals hours, rate and expenses.
- Working with international clients? The currency converter converts amounts at the rate you choose.
All the calculators are free and run in your browser. When you’re ready, put the numbers straight into the invoice generator.
FAQs
Frequently asked questions
Are these calculators free?
Yes, all of them are free with no signup.
Are the calculator results saved?
No. Calculations run in your browser and nothing is stored or sent anywhere.
General information only. This page explains common practice and is not legal, tax, accounting or financial advice. Rules differ by country, state and industry and change over time — check the requirements that apply to you, or ask a qualified professional, before relying on it. Templates and calculators are provided as-is; you are responsible for the documents you create. Read our full disclaimer.