Category
Math calculators
Free math calculators for students and professionals. Quadratic equation solver, statistics (mean/median/mode/SD), probability (nCr/nPr), GPA, logarithm, triangle (SSS/SAS), circle, fractions, percentage, unit converter, and Roman numerals. With step-by-step solutions where appropriate.
17 calculators in this category.
Days Between Dates
Count days, weeks and months between any two dates
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Percentage Calculator
Percentage of, percentage as, change, increase or decrease
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Unit Converter
Length, weight, temperature and volume — metric and imperial
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Fraction Calculator
Add, subtract, multiply, divide fractions with simplification
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GPA Calculator
4.0 standard or weighted scale, multiple courses
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Statistics Calculator
Mean, median, mode, SD, quartiles from a list of numbers
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Probability Calculator
P(A), nCr, nPr, union and intersection
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Quadratic Equation Solver
Solve ax² + bx + c = 0 — real or complex roots
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Logarithm Calculator
log₁₀, ln, log any base, and antilog
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Triangle Calculator
SSS, SAS, or right triangle — sides, angles, area
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Circle Calculator
Radius, diameter, circumference, area — any one to all four
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Random Number Generator
Integers or decimals, with or without duplicates
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Time Zone Converter
Convert wall-clock time between any cities, DST-aware
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Word Counter
Live word, character, sentence, reading-time stats
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Password Generator
Strong random passwords using your browser's crypto
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Roman Numerals Converter
Arabic to Roman and back, 1 to 3,999,999 with Vinculum
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Workday Calculator
Add business days or count working days between dates
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Frequently asked questions
Do these show the working / steps?▾
Yes for: Quadratic (discriminant + roots shown), Triangle (which formula is being used), Fraction (simplification steps), Logarithm (change-of-base shown), Percentage (multiplier and result), and Roman Numerals (each digit's contribution).
What's the GPA scale used?▾
The GPA Calculator supports the standard US 4.0 scale plus weighted scales for honours/AP courses. UAE international schools (KHDA-regulated) commonly use 4.0 unweighted; UK GCSE / A-level uses different grading. Pick the scale that matches your school's transcript.
Can I solve a triangle with only two sides?▾
Only if you have an angle too (SAS — side-angle-side) or know it's a right triangle. Two sides alone (SS) doesn't constrain a triangle. The Triangle Calculator supports SSS, SAS, and right-triangle modes — pick the one matching what you know.
Is the probability calculator for school work or actual statistics?▾
Built for both. The standard combinations (nCr) and permutations (nPr) handle homework problems. Independent and complementary event probabilities work for genuine statistical calculations. For inferential statistics (t-tests, chi-square), use a dedicated stats package.
How do I convert km to miles instantly?▾
The Unit Converter handles length (mm/cm/m/km, in/ft/yd/mi), weight (g/kg, oz/lb), temperature (°C/°F/K), and volume (ml/L, fl oz/gal). For oven cooking specifically, see the Oven Temperature Converter — it also includes Gas Mark and fan-oven equivalents.