Your numbers, not an example
Every step uses the numbers you typed, so the working matches your homework, your loan or your recipe.
Free step-by-step calculators
Calculators that show you how, not just the answer
Type your own numbers and watch the working unfold one step at a time, with pictures you can pause and replay. Free, with no sign-up.
New: a unit converter that shows the working, with land units like bigha and kathaExample: what is 15% of 200?
- Write the percentage as a division 15% means 15 out of every 100. 15% = 15 ÷ 100
- Turn it into a decimal Dividing by 100 moves the decimal point two places to the left. 15 ÷ 100 = 0.15
- Multiply by the whole Take 0.15 of 200. 0.15 × 200 = 30
- Check the answer Divide the part by the whole to get the percentage back. 30 ÷ 200 = 0.15 = 15% ✓
On qcalculate, each step animates with the numbers you type.
What makes qcalculate different
Steps you can play and pause
Watch each step animate. Go back, slow it down or replay it until it makes sense.
Math you can trust
Exact arithmetic with no rounding surprises. Every calculator is tested against known answers before it goes live.
Calculators
No calculator matches that yet. Tell us what you need.
Finance
- Loan and mortgage paymentsMonthly payment (EMI), interest and the full scheduleLive
- Compound interestWatch savings grow period by periodLive
- Simple interestInterest, principal, rate or time from I = PrtLive
- ZakatZakatable wealth, the gold or silver nisab and 2.5%Live
- UK take-home pay 2026/27Income tax, National Insurance, student loan and pensionLive
- Bangladesh income tax 2026-27Tax on your salary, slab by slab, with the investment rebateLive
- VAT, GST and sales taxAdd tax to a price, or take it out of a price that includes itLive
- Profit marginMargin and markup from cost and price, or the price for a target marginLive
- MarkupSelling price from cost and markup, and the margin it givesLive
- Credit card payoffHow long to pay off, the interest, and minimum paymentsLive
- Savings goalHow much to save each month to reach a targetComing soon
- InflationWhat money will be worth in the futureComing soon
Math
- PercentagePercent of a number, what percent, % change, adding or taking off a percentLive
- Long divisionDivide, multiply, subtract, bring down, animatedLive
- FractionsAdd, subtract, multiply, divide and simplifyLive
- Decimal to fractionIncluding repeating decimals like 0.333… and 0.1666…Live
- Fraction to decimalLong division, and whether the decimal ends or repeatsLive
- Percent to fractionAny percent as a fraction in lowest terms and as a decimalLive
- Quadratic formulaExact roots, the discriminant and a graphLive
- Polynomial divisionLong and synthetic division, with the remainder theoremLive
- Pythagorean theoremThe hypotenuse or a missing side, exactly, and is it a right triangle?Live
- Roof pitchPitch, angle, grade and rafter lengthLive
- Speed, distance and timeAny one from the other two, with the formula triangleLive
- Ohm’s lawVoltage, current, resistance and power from any twoLive
- Unit converterLength, weight, volume, temperature and more, with the units cancellingLive
- Land areaBigha, katha, decimal (shotok), kani, acres and square feetLive
- AgeExact age in years, months and days, and the next birthdayLive
- Days between datesDays, weeks, months and weekdays from one date to anotherLive
- Ratios and proportionsSimplify, share, solve proportions and the rule of threeLive
- GCF (GCD, HCF)Greatest common factor by prime factors and Euclid’s methodLive
- LCMLeast common multiple, with a Venn diagram of prime factorsLive
- Prime factorizationAn animated factor tree and the exponent formLive
- Is it prime?The square-root test, with the factors when it isn’tLive
- Number base converterBinary, octal, decimal, hex and any base from 2 to 36Live
- Decimal to binaryDivide by 2 again and again, and read the remainders upLive
- Binary to decimalAdd up the place values of the 1sLive
Statistics
- Standard deviationMean, variance and standard deviation, row by rowLive
- Mean, median, mode and rangeAll three averages and the range, with the workingLive
- Z-scoreHow far a value is from the mean, and its percentileLive
School
- Daily math puzzleFive problems a day, from easy to hard, with a score to shareNew
- GPAWeighted, unweighted and cumulative, on the 4.0 scaleLive
- CGPA (Bangladesh and India)UGC 4.00 scale, SSC and HSC GPA, and CGPA to percentageNew
- Long division practiceNew problems at three levels, with hints and worked answersLive
- Fraction practiceAdd, subtract, multiply and divide, checked instantlyLive
- Percentage practiceFrom 25% of 80 to percentage changeLive
- Printable math worksheetsLong division, fractions and percentages, with an answer keyNew
- For teachersProjector-ready steps, practice links, worksheets and lesson ideasNew
- Grade calculatorThe score you need on the final examComing soon
Why we are building qcalculate
Most calculator sites give you a number. Chatbots give you a wall of text that can contain arithmetic slips. qcalculate shows the method with your own numbers, step by step and checked by code, so you can follow it, trust it and do it yourself next time. More about qcalculate.