Free Online Calculators
Fast, accurate, privacy-friendly calculators. Every result is computed instantly in your browser — no login, no tracking scripts.
Finance
Compound Interest
Project savings growth with monthly contributions.
APY Calculator
Real annual yield from a nominal rate.
Savings Goal
Monthly deposit needed to hit a target.
Simple Interest
Interest = principal × rate × time.
Salary ↔ Hourly
Convert annual salary and hourly wage.
Tip Calculator
Split a bill, compute tip and per-person.
Percentage
P% of X, markups, and discounts.
Loan & Mortgage
Monthly payment, interest, amortization.
EMI Calculator
Equated monthly installment for any loan.
Auto Loan
Car payment from price, down, rate.
ROI Calculator
Return on investment and ROAS.
Retirement
Project your nest egg at retirement.
Loan Balance
Remaining principal after N payments.
Extra Payment
Interest & time saved by paying more.
Amortization
Month-by-month principal vs interest.
Converters
Kg to Lbs
Kilograms ↔ pounds, both directions.
Cm to Inches
Centimeters ↔ inches.
Celsius ↔ Fahrenheit
Temperature in either direction.
Km to Miles
Distance in either direction.
Currency Converter
Convert amounts with your own rate.
Discount Calculator
Sale price and amount saved.
Tax & Business
Sales Tax
Add US state/local tax to a price.
VAT & GST
Add or remove tax for UK/EU and more.
Income Tax Estimator
US federal tax, effective & marginal.
Tax Refund Estimator
Estimate your 2025 federal refund.
Profit Margin
Margin and markup from cost and price.
Lease Calculator
Monthly car/equipment lease payment.
Insurance · estimates only, not quotes
Life Insurance Need
How much coverage your family may need.
Term Life Cost
Illustrative premium from a sample rate table.
Auto Insurance
Illustrative premium by risk factors.
Home Insurance
Illustrative dwelling coverage premium.
ACA Subsidy
Estimate your marketplace premium credit.
Health & Dates
BMI Calculator
Body Mass Index with WHO category.
TDEE Calculator
Daily calories by activity level.
Age Calculator
Exact age in years, months, days.
Date Difference
Days and weeks between two dates.
Guides
How Amortization Works
Why early payments are mostly interest, and what it means to pay off early.
Extra Payments vs. Refinance
A worked comparison of two ways to cut mortgage interest.
What Is an EMI?
The formula, a worked example, and how it differs from simple interest.
Compound Interest Explained
The formula, the Rule of 72, and why time beats timing.
ROI vs. ROAS
Profit versus revenue — why a 5× ROAS can still lose money.
Income Tax: Marginal vs. Effective
Why your "bracket" isn't the rate you actually pay.
Sales Tax vs. VAT
Same total to the government, very different paperwork.
Why a Big Refund Isn't Free
A refund is your own money, returned interest-free.
BMI During Pregnancy
Why the standard categories don't apply, and what clinicians use instead.
House on an $80K Salary
From take-home pay to a purchase price, worked step by step.