Math Calculators
Boost your problem-solving skills with our math calculators, algebra tools, and equation solvers. Whether you're tackling homework, preparing for exams, or exploring concepts, Vast Calculators makes math easier and more accurate.
About Our Math Calculators
From percentages and averages to quadratic equations and special right triangles, these tools show the working, not just the answer. Each page states the exact formula, walks a numeric example step by step, and — where it helps — teaches the mental-math shortcut so you eventually don't need the calculator at all.
The percentage tools alone cover the four questions that make up most real-world math: what is X% of Y, what percent is X of Y, percentage change over time, and percentage difference between two values. If you're unsure which one you need, the percentage calculator page explains when each applies.
All 42 Math Calculators
- 30 60 90 Triangle Calculator Enter one side of a 30-60-90 triangle and this tool returns all three: the short leg opposite the 30° angle, the long le…
- 45 45 90 Triangle Calculator A 45-45-90 triangle is the isosceles right triangle: two equal legs and a hypotenuse between them. Enter either measurem…
- Age Calculator Enter a date of birth and the date you want the age measured on. Returns completed years, months and days, the same span…
- Age Difference Calculator Enter two birth dates and this calculator returns the gap between them in years, months and days, states which of the tw…
- Aspect Ratio Calculator Reduce any width and height to a ratio in lowest terms, see the shape named where the tool knows it, and get the exact h…
- Attendance Calculator Two numbers go in — how many classes have been held, and how many of them you attended — and the calculator returns your…
- Average Calculator Add a list of numbers and get the mean, with the sum and the count shown behind it — plus worked examples, a mean-vs-med…
- Cat Age Calculator Enter your cat's age in years — halves and decimals are fine for kittens — and this converter returns the rough human-ye…
- Cube Root Calculator Type any number and this calculator returns its cube root to four decimal places — the value that, multiplied by itself …
- Date Calculator Counts the days, weeks, months and years between two dates, or adds and subtracts days, weeks, months and years from any…
- Day Counter Counts the whole calendar days between today and any other date — forward for a date still ahead, backward for one alrea…
- Decimal Calculator Add, subtract, multiply or divide two decimals and round the answer to as many as ten decimal places.
- Decimal to Fraction Calculator Any terminating decimal as a fraction in lowest terms, with the place-value fraction it started from, the divisor it was…
- Digital Root Calculator Enter a whole number and this calculator adds its digits together, then adds the digits of that result, and keeps going …
- Distance Calculator Find the distance between two points: x,y coordinates with the midpoint, or two lat/long pairs as great-circle distance …
- Division Calculator Divide any two numbers and read the quotient at full precision — 22 ÷ 7 as 3.142857142857143 — with long division, a 12 …
- Dog Age Calculator Enter your dog's age in years and pick its weight class — under 20 lb, 21 to 50, 51 to 90, or over 90 — and the calculat…
- Factor Calculator Every factor of a whole number up to 10,000,000, the count, the prime factorization and the factor pairs — with a full f…
- Fraction Calculator Add, subtract, multiply or divide two fractions or mixed numbers and get the answer in lowest terms, as an improper frac…
- GCF Calculator The greatest common factor of any list of whole numbers, with Euclid's working shown line by line, a 12 × 12 GCF chart a…
- Grade Percentage Calculator Calculate your overall grade percentage across quizzes, exams and assignments, with each component's contribution shown …
- Hours to Decimal Calculator Convert hours and minutes to decimal hours (7:24 = 7.40) or decimal back to time — instantly, with the payroll conversio…
- LCM Calculator Find the least common multiple of two to ten whole numbers via the GCF identity (a × b ÷ GCF), with a 1-to-12 LCM chart,…
- Military Time Converter Convert military (24-hour) time to standard AM/PM and back — 1730 to 5:30 PM — with the hour-by-hour chart and the 0000 …
- Odds Calculator Convert odds to probability and probability back to odds, with the decimal and American betting equivalents printed besi…
- Ohm's Law Calculator Solve V = I × R from any two values — voltage, current, or resistance — plus power in watts, with the full Ohm's-law whe…
- Percentage Calculator Calculate percentages instantly with accurate results. Easy, fast, and reliable—use our Percentage Calculator now and sa…
- Percentage Increase & Decrease Calculator Work out the percentage increase or decrease between two values, with the exact change shown step by step for prices, sc…
- Pythagorean Theorem Calculator Solve right triangles with the Pythagorean theorem — hypotenuse from two legs or a leg from the hypotenuse — plus area, …
- Quadratic Equation Solver Solve ax² + bx + c = 0 for both roots, with the discriminant telling you whether they are real, repeated or complex.
- Ratio Calculator Simplify any ratio to lowest terms and solve proportions (A : B = C : x) by cross-multiplication — with 1:n form, worked…
- Recipe Conversion Calculator Scale any recipe to a new number of servings: one factor, every ingredient — with kitchen-fraction output, the cups-tabl…
- Ring Size Calculator Convert ring sizes between US numbers, UK letters, EU/ISO sizes, and millimeters — anchored on the actual measurement (d…
- Roman Numeral Converter Convert numbers to Roman numerals and Roman numerals back to numbers, 1 to 3999, with the subtractive rules, a full symb…
- Shoe Size Converter Convert shoe sizes between US men's, US women's, UK and EU from one measured foot length, with full charts and a check a…
- Slope Calculator Slope from two points — rise over run — plus the full line equation (y = mx + b), incline angle, and distance between th…
- Standard Deviation Calculator Standard deviation, variance, and mean from your data list — sample (n−1) and population (n) forms both shown, with the …
- Temperature Converter Convert Celsius to Fahrenheit and back (Kelvin included) with the exact formulas, the anchor points worth memorizing, an…
- Time Card Calculator Total your weekly or biweekly time card: clock-in and clock-out times, unpaid lunch breaks, overtime past 40 hours, and …
- Tire Size Calculator Compare two tire sizes from the sidewall code, such as 225/45R17: overall diameter change, speedometer error, circumfere…
- Volume Calculator Volume of the common solids — box, cube, sphere, cylinder, cone — in any unit, with gallons and liters conversions, all …
- Weighted Average Calculator Calculate a weighted average for grades, scores, prices, or any values with different weights. Enter value-weight pairs,…
Where Most People Start
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Percentage Calculator
All four percentage questions in one tool, plus mental-math shortcuts.
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Average Calculator
Mean, and what to do when values carry different weights.
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Quadratic Equation Solver
Roots via the quadratic formula with the discriminant explained.
Math Calculators — FAQs
Do the math calculators show the steps or just the answer?
Every calculator page includes the formula and at least one fully worked example with real numbers, so you can follow the method — useful for homework checking, not just answer-getting.
How precise are the results?
Calculations use full floating-point precision internally and round only for display (typically 2 decimal places). For chained calculations, work from the unrounded logic shown in the formula section rather than re-entering rounded intermediate results.
What's the difference between percentage change and percentage difference?
Percentage change compares a new value against an old one — it has a direction (increase or decrease). Percentage difference compares two values with no natural order, dividing their gap by their average. Use change for before/after, difference for side-by-side.