Free Math & General Calculators

    Fast, accurate math tools for percentages, unit conversions, GPA, grades, and more. Whether you're a student, teacher, or professional, these calculators handle the math so you don't have to.

    Percentage Calculator

    Three modes: Find X% of Y, calculate what percent X is of Y, or find the percent change between two numbers.

    Basic Calculator

    Standard arithmetic calculator for addition, subtraction, multiplication, and division — mobile-friendly with keyboard support.

    Unit Conversion Calculator

    Convert between length, weight, temperature, volume, speed, area, and more. Supports both metric and imperial units.

    GPA Calculator

    Calculate your semester or cumulative GPA from letter grades and credit hours. Supports standard 4.0 scale.

    Grade Calculator

    Calculate your final course grade from individual assignment scores and weights. Find what score you need to pass.

    Discount Calculator

    Calculate the sale price after a discount percentage, or find what discount was applied to reach a sale price.

    About Our Math Calculators

    Percentages are one of the most commonly misunderstood math concepts. Whether you're calculating a tip, a discount, a grade, or a tax rate, our Percentage Calculator handles all three common percentage problems with a single click.

    The Unit Conversion Calculator covers 50+ unit pairs across length, weight, temperature, volume, area, speed, and energy — the most comprehensive free conversion tool available online.

    Students use our GPA and Grade Calculators to plan their academic semester, track progress, and figure out what scores they need to hit target grades. These tools support weighted grades and any number of assignments.

    All calculators display the formula used, so you learn the math alongside getting your answer — a key part of our educational mission.

    Math Calculator FAQs

    How do I calculate a percentage?
    There are three common percentage calculations: (1) What is X% of Y? → (X ÷ 100) × Y. Example: 15% of 200 = 30. (2) X is what percent of Y? → (X ÷ Y) × 100. Example: 30 out of 200 = 15%. (3) Percentage change from X to Y → ((Y − X) ÷ |X|) × 100. Example: from 80 to 100 = +25%.
    How do I calculate percent increase?
    Percent Increase = ((New Value − Original Value) ÷ Original Value) × 100. Example: price went from $60 to $75: ((75 − 60) ÷ 60) × 100 = 25% increase. If the result is negative, it's a percent decrease. Use our Percentage Calculator's '% Change' mode to do this instantly.
    How is GPA calculated?
    GPA = Sum of (Grade Points × Credit Hours) ÷ Total Credit Hours. Grade points: A/A+ = 4.0, A- = 3.7, B+ = 3.3, B = 3.0, B- = 2.7, C+ = 2.3, C = 2.0, C- = 1.7, D = 1.0, F = 0. Example: A in 3-credit course + B in 4-credit course = (4×3 + 3×4) ÷ 7 = 24 ÷ 7 = 3.43 GPA.
    How do I convert Fahrenheit to Celsius?
    °C = (°F − 32) × 5/9. Common conversions: 32°F = 0°C (freezing), 98.6°F = 37°C (body temperature), 212°F = 100°C (boiling). Reverse: °F = (°C × 9/5) + 32. Use our Unit Conversion Calculator to convert any temperature, length, weight, or volume unit automatically.
    How do I calculate my final grade?
    Weighted Grade = Σ (Assignment Score% × Weight%) ÷ Total Weight. Example: Midterm (85%, 30 weight) + Final (92%, 40 weight) + Homework (78%, 30 weight) = (85×30 + 92×40 + 78×30) ÷ 100 = (2550 + 3680 + 2340) ÷ 100 = 85.7% (B). Our Grade Calculator does this automatically for any number of assignments.
    What is the difference between markup and margin?
    Markup is profit as a percentage of cost. Margin is profit as a percentage of selling price. Example: cost $60, sell $100 → profit $40. Markup = $40 ÷ $60 = 66.7%. Margin = $40 ÷ $100 = 40%. They're related: Markup = Margin ÷ (1 − Margin). Retail businesses typically use margin; manufacturing uses markup.
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