EAEarnwell Atlas

Browse the library

Find the right calculator

Explore 24 free calculators across money, health, dates, conversions and everyday math. Search by name or browse a topic, then review the formula and assumptions for each tool.

Browse calculators
Designed for everyday decisions✓ Private by design: calculations run in your browser✓ Mobile friendly✓ Formulas and examples

Browse the library

Choose a calculator

Plan with clarity

Money

View collection

Quick, clear calculations for spending, saving, borrowing and planning.

Percentage calculatorFind a percentage of any number.Percentage change calculatorMeasure the increase or decrease between two values.Discount calculatorSee the saving and sale price after a discount.Tip calculatorCalculate a tip and split the total between people.Sales tax calculatorAdd tax to a price or find the tax amount.Loan payment calculatorEstimate a fixed monthly payment for a loan.Compound interest calculatorEstimate growth when interest earns interest.Savings goal calculatorPlan a monthly amount to reach your savings target.Simple interest calculatorEstimate interest without compounding.Mortgage payment calculatorEstimate a monthly principal-and-interest payment.Monthly budget plannerTurn monthly take-home income into spending amounts.Profit margin and markup calculatorCompare profit, margin and markup from cost and price.Blog income calculatorEstimate ad revenue and affiliate income from page views and RPM.Hourly to salary calculatorEstimate annual, monthly and weekly gross pay from an hourly rate.

Explore the collection

Health & fitness

View collection

Straightforward health estimates with units, context and clear limits.

BMI calculatorEstimate body mass index from height and weight.BMR calculatorEstimate resting energy needs using the Mifflin–St Jeor equation.

Explore the collection

Dates & age

View collection

Find ages and count elapsed time between calendar dates.

Age calculatorCalculate age in years, months and days.Date difference calculatorCount days between two dates.

Explore the collection

Unit converters

View collection

Convert common measurements with units shown at every step.

Length converterConvert between common metric and imperial length units.Temperature converterConvert Celsius, Fahrenheit and Kelvin.

Explore the collection

Everyday math

View collection

Useful number tools for sharing costs and checking everyday figures.

Average calculatorFind the mean of a list of numbers.Ratio simplifierReduce a two-part ratio to its simplest whole-number form.Bill-splitting calculatorSplit a total evenly across a group.Fuel cost calculatorEstimate the fuel cost for a trip.

Made for real life

Beautifully simple.
Carefully explained.

Use a quick estimate, understand how it was calculated, and make your next decision with more confidence. Your entries stay in your browser.

Our approach

How we build these tools

Useful answers need clear assumptions.

We publish the formula, a worked example and the limits of each estimate. We don’t collect the values you enter into a calculator. For important financial or health decisions, use the result as a starting point and check it against your own circumstances.