Math Calculators
24 free math calculators with step-by-step working: percentages, fractions, geometry, statistics, and academic grades. From basic schoolwork to lab-grade percent error.
Percentages & proportions (9)
Percent of, percent change, discount, and proportion math. The everyday ratios you actually need.
- › Percentage Calculator
X% of Y, what % is X of Y, and add or subtract a percent from a number.
- › Proportion Calculator
Solve a/b = c/d by cross-multiplication to find the missing value.
- › Percent Change
Signed percentage difference between two numbers (negative-safe).
- › Percent Increase
Find percentage growth between an old and new value.
- › Percent Decrease
Find percentage drop between an old and new value.
- › Percent Off
Sale price after one or multiple stacked discounts.
- › Percent Error
Lab-grade experimental vs theoretical comparison.
- › Discount Calculator
Stacked coupons, sale tax, and per-person bill splits.
- › Markup Calculator
Selling price from cost + markup percent (and margin).
Fractions & decimals (4)
Fraction arithmetic, conversions, and mixed-number operations with step-by-step output.
- › Fraction Calculator
Add, subtract, multiply, and divide proper and improper fractions.
- › Mixed Fraction Calculator
Arithmetic on two mixed numbers (whole + fraction).
- › Fraction to Decimal
Convert any fraction or mixed number to decimal form.
- › Decimal to Fraction
Decimals (terminating or repeating) into simplified fractions.
Geometry & shapes (3)
Right triangles, area, and slope calculations for school and construction.
- › Pythagorean Theorem
Find any side of a right triangle from the other two.
- › Square Footage
Area of rectangles, circles, triangles, and L-shapes.
- › Roof Pitch Calculator
Convert between roof rise/run, angle, and slope percent.
Statistics (1)
Central tendency, variability, and grade summaries.
- › Mean Calculator
Average, median, mode, range, and standard deviation for any dataset.
Education & grades (4)
Grade averages, weighted grades, and GPA conversions.
- › Grade Calculator
Average scores, final-exam-needed, and percent-to-letter conversion.
- › Weighted Grade
Course grade with custom-weighted categories (homework, tests, final).
- › Semester Grade
Weighted semester grade and letter grade from each category's grade and weight.
- › GPA Calculator
College and high school GPA with weighted AP/honors support.
Dates & time (3)
Everyday date math: add or subtract time, count the days between dates, and measure durations.
- › Date Calculator
Add or subtract days, weeks, months, or years, and count days between two dates.
- › Age Calculator
Exact age in years, months, and days from a birth date to any date.
- › Time Duration Calculator
Elapsed time between two times or dates, in hours, minutes, and days.