Free online calculators — math, date/time, and academic calculators for percentages, fractions, date differences, grade averages, and more. 100% browser-based.
Online calculators for percentages, fractions, dates, grades, and everyday math — EMI-style precision without the signup. Every calculation runs in your browser; results appear as you type, and nothing you enter is ever sent to a server.
Computes X% of Y and what-percent-of-what (X is what % of Y) in two side-by-side panels with precise decimal arithmetic. Essential for everyday math — tips, discounts, tax rates, grade scores, and statistical comparisons where quick percentage answers are needed.
Raise any base to any power — squares, cubes, negative and fractional exponents with full precision. Students check 2^10 = 1024 homework in seconds — free, no signup, runs locally.
Add, subtract, multiply, and divide fractions with simplification and decimal equivalents. Split 3/4 of a bill three ways without decimal drift — free, runs locally.
Convert a Numerator/Denominator fraction to a 6-place decimal with percent and equivalents. Shows the decimal result directly. Numbers never leave your device — every calculation runs locally in your browser.
Simplify any two-number ratio to lowest terms via GCD — paint mixes, screen sizes, shares. Reduce 150:225 to 2:3 in one pass — free, runs locally.
Compute simple probability as favorable outcomes divided by total outcomes — coin flips, dice rolls, card draws. See 3 in 10 read as 30.0% instantly — free, local, no signup.
Compute nCr combinations and nPr permutations with factorial steps shown. Count 5-card poker hands (2,598,960) correctly — free, local, no signup.
Check if any number is prime. Also shows all factors and whether the number is odd or even. Numbers never leave your device — every calculation runs locally in your browser.
Find the greatest common factor (GCF/GCD) of number sets via Euclidean algorithm with steps. Reduce 48:180 to 4:15 correctly — free, local, no signup.
Calculate the remainder of division (a mod b). Shows quotient, remainder, full division expression, and negative dividend semantics. Numbers never leave your device — every calculation runs locally in your browser.
Compute mean, median, and mode for any dataset with distribution insight. See why averages mislead skewed data — free, local, no signup.
This quadratic equation solver handles ax²+bx+c=0 with roots and discriminant shown — real, repeated, or complex. Check x²−5x+6=0 gives 2 and 3 before submission — free, runs locally.
Compute circle area and circumference from the radius — geometry homework solved. Enter r=5 and read both measures at once — free, local, no signup.
Get any image or screen's aspect ratio in reduced form with common-ratio matching — 16:9, 4:3, 1:1 and custom. Check a 1920×1080 screen reads 16:9 — free, runs locally.
Compute display DPI from pixel width, pixel height, and diagonal inches — diagonal pixels over diagonal size. Compare phone and laptop sharpness honestly — free, runs locally.
Evaluate mathematical expressions with sin, cos, tan, log, and sqrt functions. A versatile scientific calculator in your browser. No signup or account required.
Convert degrees and radians both ways with π-exact forms — 180° = π rad. Stop mixing modes in calculus — free, local, no signup.
Round results to correct significant figures with rule explanations — 0.00450 has 3. Stop overstating lab precision — free, local, no signup.
Calculate gas mileage as MPG (miles per gallon) from distance driven and fuel consumed, with a metric L/100km view and trip-cost math. Numbers never leave your device — every calculation runs locally in your browser.
Calculate the percentage difference between any two numbers. Useful for comparing data sets, prices, and measurements. Numbers never leave your device — every calculation runs locally in your browser.
Evaluate arithmetic algebra expressions with + − × ÷, parentheses and decimals — digits-only evaluator, no variables. Check homework before class — free, local, no signup.
Solve geometry essentials — areas, perimeters, volumes, angles — with diagrams described. Cover homework shapes in one tab — free, local, no signup.
Compute line slope from two points with intercept form — rise over run done right. Get m and b for graphing — free, local, no signup.
Solve linear equations step by step — isolate x with operations shown. Check 3x + 7 = 22 → x = 5 before class — free, local, no signup.
Convert screen sizes between inches, cm, resolution, and aspect — compare displays honestly. Check a 27-inch 4K pixel density — free, local, no signup.
Solve proportions a/b = c/d for the fourth term — recipes, maps, dosages scale correctly. Double a 4-serving recipe to 10 without breaking ratios — free, runs locally.
Compute screen pixel density from resolution and diagonal size — compare phone sharpness honestly. A 1080p 6-inch display gives ~367 PPI — free, runs locally.
The Pythagorean theorem solves c = √(a²+b²) for the hypotenuse from two legs — ladders, ramps, screen diagonals. A 3-4-5 triangle reads c = 5.00 on site — free, runs locally.
Compute rectangle area and perimeter from length and width — flooring, paint, fencing estimates. A 12×15 ft room needs 180 sq ft of flooring — free, runs locally.
Compute square roots to four decimals — verify √144 = 12.0000 and spot irrational results instantly. Free, runs locally.
Compute population and sample standard deviation with variance, mean, median, and range for any dataset — exam scores, lab readings, quality checks. A class scoring 70±8 reads spread at a glance — free, runs locally.
Convert decimals to exact fractions — 0.75 to 3/4 with repeating-decimal support. Get exact answers for homework — free, local, no signup.
Calculate the number of ways to arrange k items from n items (nPr). Shows the step-by-step permutation calculation. Numbers never leave your device — every calculation runs locally in your browser.
Calculate the factorial of any number (n!). Handles large numbers and shows the full multiplication sequence. Numbers never leave your device — every calculation runs locally in your browser.
Break any integer into prime factors with factor trees — 60 = 2²×3×5 shown stepwise. Ace number theory homework — free, local, no signup.
Find LCM of number sets for scheduling cycles and fraction denominators. Sync 4-day and 6-day rotas every 12 days — free, local, no signup.
Compute logarithms (logs) in any base with change-of-base steps and natural/common presets. Solve log₂(32) = 5 instantly — free, local, no signup.
Compute trigonometry: sin, cos, tan in degrees or radians with triangle solving. Find the opposite side from 30° hypotenuse 10 (= 5) — free, local, no signup.
Convert between standard and scientific notation — 6,020,000,000 ↔ 6.02×10⁹. Handle Avogadro-scale numbers cleanly — free, local, no signup.
Round numbers using 5 modes: round half up, banker's rounding, floor, ceil, and truncate. Shows step-by-step explanation with the digit being rounded. Numbers never leave your device — every calculation runs locally in your browser.
Compute distance, midpoint, and slope between coordinate points — geometry essentials. Get all three from two points — free, local, no signup.
Calculate triangle area three ways — base and height, three sides (Heron), or two sides plus included angle. Pick the method matching your knowns. Numbers never leave your device — every calculation runs locally in your browser.
Computes exact age in years, months, and days from a given birth date relative to any target date. Numbers never leave your device — every calculation runs locally in your browser.
Count working days between two dates excluding weekends — HR teams prorate leave and payroll accurately. A 20-day leave request spans 28 calendar days — free, no signup, runs locally.
Find the weekday for any Gregorian date — plan anniversaries, verify old records, settle bets. Check what day you were born in seconds — free, no signup, runs locally.
Convert any date to its day-of-year number (1–365/366) with days remaining. Developers compute ordinal dates for logs and filenames — free, no signup, runs locally.
Test any year for leap status with the full Gregorian rule — divisible by 4, except centuries unless divisible by 400. Settle the 1900 vs 2000 debate instantly — free, runs locally.
Count down the time until any future moment in days, hours, minutes, and seconds — launches, deadlines, events. See 45 days to launch live — free, local, no signup.
Measure the exact gap between two dates in days, weeks, and months — tenures, ages, project spans. A 3-year job stint reads 1,096 days instantly — free, no signup, runs locally.
Get ISO week numbers for any date — plan sprints and fiscal weeks correctly. Know Week 32 means late July instantly — free, local, no signup.
Calculate total work hours for a single shift between start and end times with one configurable break. Essential for timesheets and payroll. Numbers never leave your device — every calculation runs locally in your browser.
Estimate travel time from distance and speed — with optional arrival time and traffic buffer. Add traffic buffers and arrival targets for realistic plans — free, local, no signup.
Calculate the exact duration between two times. Handles overnight time spans and displays results in hours, minutes, and seconds. Numbers never leave your device — every calculation runs locally in your browser.
Add hours and minutes to any time — shift schedules, compute end times, total durations. Add 8h30m to 9:00 for shift end — free, local, no signup.
Find meeting slots across attendee time zones with working-hours overlap. Schedule standups spanning continents fairly — free, local, no signup.
Add or subtract days, weeks, months, and years from any date — calendar-accurate. Find 100 days from hire date exactly — free, local, no signup.
Measure exact elapsed time since any moment — days, hours, minutes live. Track 100 days sober to the second — free, local, no signup.
Check DST observance and transition dates for any timezone — spring forward dates decoded. Never miss a global meeting again — free, local, no signup.
Add and subtract hours:minutes durations — timesheets, shifts, project totals. Sum 7:30 + 8:15 correctly — free, local, no signup.
Compute your overall course percentage from comma-separated assignment grades and their matching weights — Exam Heavy presets included. Numbers never leave your device — every calculation runs locally in your browser.
Compute semester GPA from course grades and credit hours with credit-weighted math on the standard 4.0 scale — quick academic snapshot. See what straight B's earn — free, local, no signup.
Convert a single course percentage into its letter grade on the built-in plus/minus scale — see that an 85 earns a B instantly. Free, local, no signup.
Compute semester GPA from course grades and credit hours with weighted math. Students check what an A in a 4-credit lab does before finals — free, no signup, runs locally.
Plan study hours from syllabus weight and days left — pass with scheduled effort. Turn 5 chapters in 10 days into daily targets — free, local, no signup.
Compute test percentages and grades from correct/total with curve options. Turn 42/50 into 84% (B) instantly — free, local, no signup.
Estimate pages from word count and font size — about 500 words/page at 12pt, 600 at 10pt and under. Font-size-only math, no spacing or margin inputs — free, local, no signup.
Works offline after first load · Pro unlocks 500-file batches and 2GB files
Subtract old from new, divide by old, multiply by 100. Going from 40 to 50 is a 25% increase — the percentage calculator handles increase, decrease, and reverse-percentage in one place.
Multiply each score by its weight, sum those products, and divide by total weight. A 90 on a 60%-weighted exam plus 70 on 40% coursework averages 82, not 80.
Enter both dates to get exact days, weeks, and months between them — useful for notice periods, warranties, and age calculations. Results account for leap years automatically.
Yes — decimal math avoids the floating-point errors that make 0.1 + 0.2 equal 0.30000000000000004 in spreadsheets. Financial figures round correctly to paise and cents.