Built for People Who Want Real Answers
NerdyTools is a free online calculator and tools hub built for anyone who needs fast, accurate answers โ without paywalls, sign-ups, or ads pretending to be content.
Built Around Real Problems
Every tool on NerdyTools exists because someone needed it. From working out stamp duty on a first home to calculating startup runway at 2am โ these are real-world calculations, not textbook exercises.
Your Data Stays in Your Browser
Every calculation runs locally in your browser. NerdyTools never collects, stores, or transmits the numbers you enter โ whether that's your salary, your mortgage balance, or your body weight.
Formulas You Can Trust
All tools use industry-standard formulas verified against authoritative sources โ ATO for Australian tax, IRS for US tax, WHO for health metrics, and RBA for financial rates. No guesswork, no outdated numbers.
"No satisfaction with mediocre tools. So we built better ones."
Built by: Anam Ahmed โ Senior Consultant, PwC Digital Technology Services, Sydney
300+ Free Calculators Across Every Category
Whether you're planning your finances, tracking your health, building a startup, or managing a property โ there's a NerdyTools calculator for it. No spreadsheets, no formulas to memorise, no account required.
Finance & Money
Plan your money with calculators for mortgages, investments, loans, savings, budgets, taxes, and retirement. Covers Australia, US, and UK tax rules.
Mortgage Calculator ยท Loan Calculator ยท Compound Interest Calculator ยท Investment Calculator ยท Retirement Calculator ยท Salary Calculator ยท Credit Card Calculator ยท Budget Planner ยท Savings Calculator ยท Tax Calculator ยท Dividend Calculator ยท CAGR Calculator ยท Percentage Calculator
Business & Startups
Calculate burn rate, runway, CAC, LTV, ROAS, EBITDA, MRR, ARR, and more. Tools used daily by founders, marketers, and finance teams.
Burn Rate Calculator ยท Runway Calculator ยท ROAS Calculator ยท CAC Calculator ยท LTV Calculator ยท EBITDA Calculator ยท Break-Even Calculator
Health & Fitness
Calculate BMI, daily calories, macro targets, ideal body weight, water intake, and pregnancy due dates using WHO and NIH-referenced formulas.
BMI Calculator ยท Calorie Calculator ยท Macro Calculator ยท Body Fat Calculator ยท Pregnancy Calculator ยท Water Intake
AI & Developer Tools
Count tokens, estimate API costs, compare LLM models, format JSON, decode JWTs, generate cron expressions, and more โ built for developers and AI engineers.
AI Token Counter ยท LLM Cost Calculator ยท JSON Formatter ยท JWT Decoder ยท CSS Gradient Generator ยท Base64 Encoder ยท Color Picker ยท Cron Generator
Australian Finance
ATO-verified calculators for stamp duty, superannuation, HECS repayments, capital gains tax, novated leases, payroll tax, and the latest 2025-26 rates.
Stamp Duty Calculator ยท Super Calculator ยท HECS Calculator ยท CGT Calculator ยท Novated Lease ยท Negative Gearing
Math, Date & Converters
Percentage calculators, fractions, averages, GPA, unit conversions, currency, date difference, age calculator, countdown timers and more.
Percentage Calculator ยท Matrix Calculator ยท Number Base Converter ยท Age Calculator ยท Unit Converter ยท Currency Converter ยท GPA Calculator ยท Date Difference
How Our Tools Are Built
Every calculator on NerdyTools follows the same standard: accurate formula, plain-English explanation, worked example, and a result you can actually understand.
Industry-Standard Formulas
Every calculation uses the same formula a bank, accountant, or doctor would use. Sources cited inline.
AU, US & UK Coverage
Tax rates, thresholds and rules are jurisdiction-specific. NerdyTools covers Australia, the United States, and the United Kingdom.
Instant, No Sign-Up
Results appear the moment you type. No account, no email, no waiting. Just the answer you came for.
Works on Any Device
Every tool is fully responsive. Use NerdyTools on your phone, tablet, or desktop โ no app download needed.
| Feature | NerdyTools | Generic Sites | Spreadsheets |
|---|---|---|---|
| Free to use | โ | Sometimes | โ |
| No sign-up required | โ | โ | โ |
| AU/US/UK tax rates | โ | โ | โ |
| Data stays in browser | โ | โ | โ |
| Mobile responsive | โ | Varies | โ |
Our Most Popular Calculators
The tools people reach for most โ for big financial decisions, daily health tracking, and everything in between.
Mortgage Calculator
Monthly repayments, total interest, and full amortisation schedule for any home loan.
Compound Interest
See exactly how your savings or investments grow over time with daily, monthly, or annual compounding.
BMI Calculator
Body Mass Index in metric or imperial, with WHO weight category and healthy weight range.
Burn Rate Calculator
Monthly cash burn and runway for startups. Know how long your money lasts before you run out.
Stamp Duty Calculator
All 8 Australian states and territories. Updated for 2025-26 with first home buyer concessions.
Retirement Calculator
Project your retirement balance and see if you're on track โ with inflation adjustment and contribution modelling.
Frequently Asked Questions
Everything you need to know about NerdyTools.
What is NerdyTools?
NerdyTools is a free online calculator and tools hub with 300+ tools covering personal finance, business metrics, health, math, tax, AI, and developer utilities. Every tool runs in your browser with no sign-up required.
Are all NerdyTools calculators free?
Yes โ every single tool on NerdyTools is completely free. There are no paid tiers, no premium features, and no subscription. The site is supported by non-intrusive advertising.
Do I need to create an account?
No. You can use every tool on NerdyTools without creating an account, entering an email address, or providing any personal information. Just open the tool and start calculating.
How accurate are the calculations?
All calculations use industry-standard formulas verified against authoritative sources โ ATO for Australian tax, the IRS for US tax, HMRC for UK tax, WHO and NIH for health metrics, and the RBA for financial rate benchmarks. Tax rates and thresholds are reviewed and updated for the current financial year.
Is my data private?
Yes. All calculations run entirely in your browser using JavaScript. NerdyTools never collects, stores, or transmits the numbers you enter โ whether that's your salary, mortgage balance, health metrics, or business financials. Your data never leaves your device.
What countries does NerdyTools cover?
NerdyTools has dedicated calculators for Australia, the United States, and the United Kingdom โ including jurisdiction-specific tax rates, thresholds, and rules. Many tools also work globally for universal calculations like BMI, compound interest, or unit conversion.
Does NerdyTools work on mobile?
Yes. Every NerdyTools calculator is fully mobile-responsive and works on smartphones, tablets, and desktops. No app download is required โ just open your browser and go.
How often are tools updated?
Tax calculators are reviewed at the start of each financial year (July for Australia, April for the UK, January for the US) and updated whenever rates or thresholds change. New tools are added regularly based on user requests and emerging needs.
Explore All NerdyTools By Categories
Find the right tool for any task โ free, fast, and no sign-up required