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Calculators for the numbers behind your grades, your pay and your prices.
For the math that comes up at school and at work, with the formula, a worked example and the sources on every page.
Grades & GPA
View all grades & gpa calculators- Weighted GPA CalculatorWeighted and unweighted GPA with honors and AP classes.
- Final Grade CalculatorThe final exam score you need for your target grade.
- College GPA CalculatorSemester and cumulative GPA from grades and credit hours.
- Test Grade CalculatorPercent and letter grade from questions wrong or points.
Math & Percentages
View all math & percentages calculators- Mixed Fraction CalculatorMixed numbers and fractions with whole numbers, with steps.
- Discount CalculatorSale price, savings and stacked percent-off discounts.
- Percentage CalculatorPercent of a number, percent of a total, or the whole.
- Percentage Increase CalculatorPercent increase or decrease, and reverse a change.
- Decimal to Fraction CalculatorExact fractions from decimals, even repeating ones.
- Fraction to Decimal CalculatorLong division to an exact or repeating decimal.
- Simplify Fractions CalculatorLowest terms, equivalent fractions and target denominators.
- GCF CalculatorGreatest common factor with prime factors and Euclid’s steps.
- LCM CalculatorLeast common multiple and least common denominator.
- Ratio CalculatorSimplify ratios, solve proportions, split totals.
- Aspect Ratio CalculatorScreen, video and photo ratios and resize dimensions.
- Average CalculatorMean, median, mode, range and weighted average.
- Standard Deviation CalculatorSample or population SD and variance, with steps.
- Z-Score CalculatorZ-scores, percentiles and the value at a percentile.
- Tip CalculatorTip, total and split per person.
- Percent Error CalculatorMeasured vs accepted value, signed or absolute.
- Scientific CalculatorTrig, logs, powers, roots and factorials, typed as an expression.
- Pythagorean Theorem CalculatorMissing side of a right triangle, with steps.
- Mean Absolute Deviation CalculatorAverage distance from the mean, step by step.
- Probability CalculatorTwo events, conditional odds and repeated trials.
- Scientific Notation CalculatorPowers of ten, e-notation and sig figs.
- Slope CalculatorRise over run, y = mx + b and a graph.
- Area CalculatorArea of common shapes in any unit.
- Volume CalculatorVolume and surface area of solids.
- Right Triangle CalculatorSOH CAH TOA: missing sides and angles.
- Factor CalculatorAll factors, factor pairs and primes.
- Square Root CalculatorSquare, cube and nth roots, simplified.
- Exponent CalculatorPowers with negative and fraction exponents.
- Log Calculatorlog, ln, any base and antilog.
- Quadratic Formula CalculatorExact and decimal roots, vertex and graph.
- Rounding CalculatorAny place or multiple, five rounding rules.
- Quartile CalculatorQ1, Q3, IQR, outliers and a box plot.
- Percentile Calculatorkth percentile and percentile rank from data.
- Confidence Interval CalculatorMean or proportion, with margin of error.
- Sample Size CalculatorResponses needed for a margin of error.
- Permutation and Combination CalculatornPr, nCr and letter arrangements.
- Expected Value CalculatorE(X), variance and SD from a probability table.
- Triangle CalculatorSolve SSS, SAS, ASA, AAS and SSA triangles.
- Linear Regression CalculatorLine of best fit, r and r², with a scatter plot.
- System of Equations CalculatorExact solutions for 2×2 and 3×3 linear systems.
- Long Division CalculatorStep-by-step long division, remainders or decimals.
- Number Sequence Calculatornth term and sums of arithmetic and geometric sequences.
- Random Number GeneratorFair random numbers, with or without repeats.
- Modulo CalculatorRemainders and a mod n, negatives included.
Business & Pricing
View all business & pricing calculators- Markup CalculatorSelling price, markup and margin from your cost.
- Commission CalculatorFlat or tiered sales commission, with base pay.
- Real Estate Commission CalculatorListing and buyer-side commission, agent split, seller net.
- ROAS CalculatorReturn on ad spend, ACoS and break-even ROAS.
- Profit Margin CalculatorGross, operating and net margin for a period.
- Break-Even CalculatorBreak-even units and sales, target profit, safety margin.
- Unit Price CalculatorPrice per ounce, pound, liter or item, side by side.
- CPM CalculatorCost per 1,000 impressions, with CTR, CPC and CPA.
- Price Elasticity CalculatorMidpoint elasticity of demand or supply.
- PayPal Fee CalculatorPayPal fees, what you keep and what to charge.
Pay & Salary
View all pay & salary calculators- Pay Raise CalculatorNew pay from a raise %, or the % from old and new pay.
- Overtime CalculatorTime-and-a-half pay for the week, bonuses included.
- PTO CalculatorPTO accrual per pay period, balance and payout value.
- Salary to Hourly CalculatorHourly wage to salary and back, per pay period.
- Time Card CalculatorWeekly hours from clock times, with breaks and overtime.
- Freelance Rate CalculatorThe hourly and day rate that covers income, expenses and time off.
- Compa-Ratio CalculatorPay as a % of the range midpoint, and position in range.
- Time to Decimal Calculator8:45 → 8.75 hours, and back again.
- Hours and Minutes CalculatorAdd, subtract, multiply or divide durations.
- Mileage Reimbursement CalculatorMiles × rate, with the 2026 IRS rates built in.
Show the work
A calculator is only useful if you can check it. Every page explains the method in plain English, so you can redo the math by hand or explain it to a teacher, a client or a boss.
Formula first
Each calculator prints the formula it uses and a worked example you can follow.
Published sources
Rules come from school and registrar policies, federal regulations, open textbooks and extension guides, linked on the page.
Your rules, not ours
Bonuses, cutoffs and targets are editable, so the result matches your school or your business.
Private and fast
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