Shopping & TaxPopular
Percentage Calculator
Calculate percentages, percentage change, difference and add/subtract in one page.
Open Percentage CalculatorAccurate calculations made simple
Free Business, Marketing and Financial Calculators
Make faster decisions with clear, accurate, and easy-to-use calculators for business, marketing, finance, and online growth.
Most Popular
Percentage Calculator
Calculate percentages, percentage change, difference and add/subtract in one page.
Popular calculators
The tools people reach for most often — percentages, discounts, margins, interest and tax.
Shopping & TaxPopular
Discount Calculator
Calculate sale price, savings, stacked discounts and effective discount percentage.
Open Discount CalculatorFinancePopular
Compound Interest Calculator
Calculate compound interest, future value and contributions with a yearly breakdown.
Open Compound Interest CalculatorBusinessPopular
Profit Margin Calculator
Find gross, operating or net margin from revenue and cost figures.
Open Profit Margin CalculatorShopping & TaxPopular
Sales Tax Calculator
Add or remove sales tax using any custom rate, with quantity support.
Open Sales Tax CalculatorMarketingPopular
ROAS Calculator
Measure revenue generated for each unit of advertising spend.
Open ROAS CalculatorWhy use CalcMetrio
Free to use
Every calculator on the site is available at no cost, with no usage limits.
No registration required
You never need an account, an email address or a subscription.
Private browser-based calculations
Figures you type are processed in your browser wherever technically possible.
Clear formulas
Each page shows the formula used and a worked example, so results can be checked by hand.
Mobile friendly
Numeric keyboards, large tap targets and a layout that works on slow connections.
Understanding the numbers behind your decisions
CalcMetrio is a growing library of single-purpose calculators for the everyday arithmetic of running a business: pricing a product, checking whether a campaign paid for itself, working out how many sales cover the rent. Each tool does one job, states the formula it uses, and shows a worked example so you can reproduce the result on paper if you want to.
How our calculators are verified
Formulas are taken from standard business, accounting and marketing definitions, then tested against manually calculated examples across ordinary values, zero values, very large values and decimals. Pages are re-checked when a definition is ambiguous or when a reader reports a discrepancy, and each calculator page carries the date it was last reviewed. Our [object Object] explains the process and how to request a correction.
Why you should still check important decisions
A calculator only reflects the assumptions in its inputs. Tax treatment, accounting standards, contract terms and local regulation all change the picture, and a single percentage cannot capture them. Treat every output here as an estimate that helps you frame a question, and confirm anything consequential with your accountant, financial adviser or another qualified professional.
Popular guides
Plain-English explainers on margin, pricing and campaign measurement are being written alongside the calculators.
Practical calculator guides
Read focused guides that pair a business or marketing concept with the calculator that applies it, including sales tax, ROAS, ROI, markup and margin.
Browse calculator guides