Free Online Calculators & Tools
Calculate percentages, loans, compound interest, and much more with our easy-to-use tools.
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Popular Calculators
Percentage of a Number
Calculate what a certain percentage of a number is. Useful for discounts, tips, taxes, and other percentage-based calculations.
How to: Enter the number you want to calculate a percentage of
Loan Payment Calculator
Calculate your loan payment, total interest, and repayment cost. Estimate monthly payments for personal loans, auto loans, and mortgages.
How to: Enter the loan amount - the total amount you are borrowing (principal)
Add Percentage to Number
Increase a number by a certain percentage. Useful for calculating price increases, salary raises, and growth rates.
How to: Enter the base number you want to increase
Subtract Percentage from Number
Decrease a number by a certain percentage. Useful for calculating discounts, price reductions, and decreases.
How to: Enter the base number you want to decrease
Compound Interest Calculator
Calculate how your investment grows over time with compound interest. See the final amount, total contributions, and interest earned.
How to: Define your initial investment amount - the starting balance you invest today
Love Compatibility by Birth Date
Blend two names and birthdays to get a playful compatibility score with a quick insight.
How to: Enter both names exactly how you prefer to be called
Zodiac Compatibility Checker
Enter two birth dates to reveal their zodiac signs, compatibility score, and a short interpretation.
How to: Enter two birth dates (any year works).
Numerology Compatibility (Life Path Numbers)
Turn two birth dates into life path numbers, compare the pairing, and read a friendly interpretation.
How to: Enter any two birth dates (past or present).
Friendship Compatibility Calculator
Enter two birth dates to see a playful friendship score plus communication, trust, and energy highlights.
How to: Enter each friend’s birth date (no need for year alignment).
Work & Team Compatibility Calculator
Enter two birth dates to see collaboration, communication, and planning scores plus tailored teamwork tips.
How to: Enter both birth dates. Year does not need to match.
Birth Date Compatibility Calculator
Compare two birth dates to get a playful compatibility score with communication, emotional, and lifestyle breakdowns.
How to: Enter two birth dates (any calendar year works).
Auto Loan Calculator
Estimate your car loan payment, interest cost, and total vehicle price. Calculate monthly payments with down payment, trade-in, taxes, and fees.
How to: Enter the vehicle price - the total cost of the car you want to purchase
Classic Utilities
Learn & Guides
Learn →How to Calculate Loan Payment
Learn how to calculate your monthly loan payment using the standard loan formula.
Estimation vs Engineering Design – What Calculators Can and Cannot Do
Understand the difference between early estimates and full engineering design so you can use calculators responsibly.
What is Percentage of a Number
Learn what percentage means and how to calculate a percentage of any number.
Engineering Standards
Standards →Eurocode 1: Actions on structures
European standard for determining actions on structures, including loads and impacts.
ISO 8601: Date and time representation
International standard for date and time representation in data interchange.
United States
United States building practice relies on a family of national reference documents such as the International Building Code (IBC), ASCE 7 load provisions, and ACI concrete guides.
Educational and estimation purposes only.