Skip to main content
Calculator Answers
Every answer shows its work

The calculator that just answers the question.

Get the answer first, then the formula and every step behind it.

Free · Calculations run in your browser

Try:What's a good SAT score?How much concrete do I need?How old is my dog in human years?What will my Roth IRA grow to?

Popular calculators

When Is My Birthday?

Find your next birthday, the weekday it falls on, and how many days…Everyday Life

Calorie Deficit

Work out a daily calorie deficit from your maintenance estimate and…Health

Overtime Pay

Calculate gross pay from regular and overtime hours at any multiplier…Money

Grade

Calculate your current class grade by entering your assignment…Education

Age

Find a completed age in years, months and days on any date, with…Everyday Life

Circle Area Formula

Calculate the area of a circle from the radius, diameter…Education

Scientific

Free online scientific calculator with sin, cos, tan, asin, acos…Education

TDEE

Estimate your Total Daily Energy Expenditure from sex, age, height…Health

Tip

Split a bill, calculate a fair tip, and round amounts cleanly across…Money

BMI

Compute Body Mass Index from height and weight, with the standard…Health

Roth IRA

Project the future value of a Roth IRA from current balance, annual…Money

Percentage

Use this percent calculator to find the percentage of a number, what…Education

College GPA

Calculate your semester GPA and updated cumulative GPA on the…Education

Final Grade

Calculate what score you need on your final exam to pass the class or…Education

Celsius to Fahrenheit

Convert Celsius to Fahrenheit. Find the direct temperature answer…Conversions
Browse all 673 calculators

Browse

Every calculator, by category

Eleven categories, each with its own page explaining what the tools do and which one answers your question.

  • Education

    Grades, GPA, statistics, algebra and geometry, each one showing the working behind the answer.

  • Home

    Concrete, gravel, paint, flooring and square footage, sized from measurements you can take yourself.

  • Money

    Loans, mortgages, paychecks, taxes and savings, worked the way a lender or a payroll run does it.

  • Writing

    Word, character and syllable counts, reading time and readability, updating as you type.

  • Pets

    Dog and cat ages in human years, plus food and calorie planning, from current veterinary research.

  • Gematria Tools

    Gematria in English, Hebrew and Greek, with transliteration converters for the source alphabets.

  • Health

    BMI, BMR, TDEE, body composition and target heart rate, from the standard published formulas.

  • Everyday Life

    Birthdays, ages, date arithmetic and countdowns to the day that matters.

  • Unit Converters

    Interactive converters for length, weight, temperature, volume, speed and data storage.

  • Conversions

    Direct answers to how many of one unit fit in another, with the tables behind them.

  • PDF Tools

    PDF merging, splitting and conversion, running entirely in your browser.

How Calculator Answers is different

More than a number.

Most calculators stop at the result. Calculator Answers gives you the answer first, then the formula, the values it used, and the steps behind it. That makes the result easier to understand and easier to check.

Read the methodologyEmbed calculators on your site
Result

Tip amount

$17.20

on an $86.00 bill at 20%

Formulatip = bill × 20%
Step$86.00 × 0.20 = $17.20
Total with tip$103.20
A 20% tip is one fifth of the bill. Here that adds $17.20, so you hand over $103.20 in all.
Answer first
The result shows before any explanation.
Formula included
The equation, with your numbers in it.
Steps explained
How your numbers became the answer.
Plain-language guidance
What the result means, in plain English.

Guides and formulas

Learn the formulas behind the answers

Plain-English guides for percentages, GPA, final grades, TDEE, mortgage payments, and standard deviation.

All guides
part ÷ whole × 100How to Calculate a PercentageThree formulas for percent of, change, and discounts7 min readΣ(points × credits) ÷ Σ(credits)How to Calculate GPAGrade points to 4.0 GPA, weighted and unweighted6 min read(target − current × (1 − w)) ÷ wHow to Calculate Your Final GradeWhat you need on the final to hit your target7 min readBMR × activity factorHow to Calculate TDEEFrom BMR and activity level to daily calories7 min readM = P·r(1+r)ⁿ ÷ ((1+r)ⁿ − 1)How to Calculate a Mortgage PaymentPrincipal, interest, taxes, and PMI in one payment8 min readσ = √(Σ(x − μ)² ÷ N)Standard Deviation FormulaSample vs population, computed step by step7 min read

FAQ

Frequently asked questions

A quick read on what the site does, what is free, and how citations and embeds work.

Calculator Answers is a free collection of online calculators for math, grades, health, money, writing, pets, home projects, and Bible study. Each calculator gives a clear answer, shows the formula, and explains the steps so you can understand the result.

Yes. Every calculator is free to use.

Yes. Each calculator page has a How it works section with the actual formula plus a step-by-step breakdown that uses your numbers, so you can see exactly how the answer was built.

Yes. The Cite button on every calculator page produces ready-to-paste citations in plain, MLA, and APA formats, with the canonical page URL and today's access date.

Yes — 632 calculators have real iframe embed pages (see our embed calculators page). The Embed button on each calculator page shows the right code.

Calculations run inside the page in your browser; the numbers you type are used to compute the answer locally. The Helpful button on each calculator records a page-level helpful count (whether visitors found a calculator helpful), not the inputs you entered.

FOR SITE OWNERS

Put a calculator on your site.

Any of our calculators can be embedded with one iframe snippet. Free to embed, no key required, and the step-by-step answer comes with it.

Read the methodologyGet the embed code