Free · No sign-up · Works on mobile & desktop
Scientific Calculator Online — Free Loan EMI, LCM, Ratio, Percentage, Age, Date, Salary & BMI Calculators
Calculator AI is one page of free calculators people search for every day. Start with the scientific calculator online — sin, cos, tan, log, ln, powers, roots and factorials with full history — then scroll for eleven more tools: loan EMI calculator, LCM & GCF calculator, ratio calculator, percentage calculator, age calculator, date calculator, salary calculator, BMI calculator, unit converter and word counter. No sign-up, no downloads, instant answers right in your browser.
Popular calculators: EMI calculator · Age calculator · Zakat calculator · LCM & GCF calculator
Popular right now: loan EMI · LCM of 12 and 18 · simplify a ratio · days between dates · km to miles · kg to lbs · what is 20% of 1500? · check my BMI · how old am I?
How to use the scientific calculator
Type an expression with the keypad or your keyboard, then press =. The calculator follows the standard order of operations — parentheses first, then powers, then multiplication and division, then addition and subtraction — so 2 + 3 × 4 correctly gives 14, not 20.
- Trigonometry: sin, cos, tan and their inverses (sin⁻¹, cos⁻¹, tan⁻¹). Use the DEG/RAD toggle — school and exam maths is almost always degrees; calculus is usually radians.
- Logarithms: log is base 10, ln is the natural log (base e). So log(1000) = 3 and ln(2.71828…) = 1.
- Powers and roots: xʸ raises to any power, x² squares, and √ takes a square root. You can chain them: √(3² + 4²) = 5.
- Factorial (n!): multiplies a whole number by every positive integer below it — 5! = 120. Handy for probability and combinations.
- Percent (%): works as “percent of the previous value” — 200 + 10% = 220, and 50% on its own = 0.5.
- History: every finished calculation is saved in the panel beside the calculator. Tap a result to drop it back into the display and keep calculating.
Formulas used by these tools
Percentage of a number = (percent ÷ 100) × number
Percentage change = ((new − old) ÷ old) × 100
Loan EMI = P × r × (1 + r)ⁿ ÷ ((1 + r)ⁿ − 1), where r = monthly interest rate, n = months
LCM(a, b) × GCF(a, b) = a × b · e.g. LCM(4, 6) = 12, GCF(12, 18) = 6
Simplify a ratio: divide both sides by their GCF — 12 : 18 → 2 : 3
Hourly pay = annual salary ÷ 52 ÷ hours worked per week
BMI = weight (kg) ÷ height (m)²
°F = (°C × 9 ÷ 5) + 32 · K = °C + 273.15
Reading time ≈ words ÷ 200 words per minute
Which tool should you use?
Students will live in the scientific calculator, the LCM & GCF calculator and the percentage calculator (exam marks are just “X is what percent of Y”). Borrowers can check a loan EMI before signing anything, and job-seekers can convert a monthly salary offer into hourly and annual pay with the salary calculator. Anyone planning ahead uses the date calculator for deadlines, visas and countdowns, and the ratio calculator for recipes, screen sizes and mixtures. Anyone tracking health can check BMI in seconds and convert kilograms, pounds, centimetres and feet without a second app. Writers and speakers use the word counter to hit essay lengths and estimate how long a speech will take out loud. And the age calculator settles the “exactly how old am I?” question for forms, birthdays and official documents — down to the day.
Why use this free online calculator instead of an app?
⚡ Instant — no download
Open the page and calculate. No app install, no sign-up, no ads blocking the keypad. Bookmark it and it is always one tap away on phone or laptop.
🎓 Made for students & exams
DEG mode for school trig, log / ln, powers and factorials for maths and science homework — plus a percentage calculator for marks and a word counter for essays.
🔒 Private & free forever
Every calculation runs in your browser. Your numbers, date of birth and text never leave your device, and every tool is 100% free with no limits.
Popular conversions & calculations people search for
Jump straight to the tool — or check the quick answers below. For any other value, use the unit converter above: it updates instantly as you type.
Worked examples — try them in the calculator above
- Right triangle: √(3² + 4²) = 5 — type √(3² + 4²) in the scientific calculator.
- Discount: a Rs 2,500 item at 20% off — 20% of 2500 is 500, so you pay Rs 2,000. Use the percentage calculator.
- Exam percentage: 45 marks out of 60 — “45 is what percent of 60?” = 75%.
- Travel: a 10 km run is 6.21 miles — convert it live in the unit converter.
Frequently asked questions
Is this scientific calculator free to use?
Yes. Every tool on this page is completely free, with no sign-up, no downloads and no limit on how many calculations you run.
How do I switch between degrees and radians?
Tap the DEG/RAD toggle above the keypad. In DEG mode, trig functions read angles in degrees; in RAD mode they read radians. The setting applies to sin, cos, tan and their inverses.
What is the difference between log and ln?
log is the base-10 logarithm and ln is the natural logarithm (base e ≈ 2.71828). For example, log(1000) = 3, while ln(e) = 1.
How is BMI calculated, and what is a healthy range?
BMI = weight in kilograms divided by the square of height in metres. For adults, 18.5–24.9 is generally classed as healthy, below 18.5 as underweight, 25–29.9 as overweight and 30 or above as obese. BMI is a general guide, not a medical diagnosis.
How does the age calculator work?
It counts full years from your date of birth, then full months, then the remaining days — the same way age is written on official forms. It also shows your total days lived and days until your next birthday.
How do I use the scientific calculator online?
Type your expression with the on-screen keypad or your physical keyboard, then press =. It supports sin, cos, tan, log, ln, powers (xʸ), square roots, factorials, percentages, π and e — with the correct order of operations, so 2 + 3 × 4 gives 14.
How do I calculate a percentage online?
Use the percentage calculator above: for “what is X% of Y?” enter the percent and the number; for exam marks use “X is what percent of Y?”; for price or salary changes use percentage increase / decrease.
What units can I convert — km to miles, kg to lbs, °C to °F?
Length (mm, cm, m, km, inch, foot, yard, mile), weight (mg, g, kg, tonne, oz, lb) and temperature (Celsius, Fahrenheit, Kelvin) — results update instantly as you type, with a one-tap swap button.
How is a loan EMI calculated?
EMI = P × r × (1 + r)ⁿ ÷ ((1 + r)ⁿ − 1), where P is the loan amount, r is the monthly interest rate (annual rate ÷ 12 ÷ 100) and n is the number of monthly payments. The loan calculator above also shows the total interest and total payment, so you can see the real cost of a car, personal or home loan before you sign.
What is the difference between LCM and GCF?
LCM (least common multiple) is the smallest number that is a multiple of all your numbers — for 4 and 6 it is 12. GCF (greatest common factor, also called HCF) is the largest number that divides all of them — for 12 and 18 it is 6. A quick check for two numbers: LCM × GCF = the two numbers multiplied together.
How do I simplify a ratio?
Divide both sides by their greatest common factor: 12:18 ÷ 6 becomes 2:3. The ratio calculator does this for any two numbers and can also solve an equivalent ratio — if A : B = C : D, it finds the missing value D.
How do I count days between two dates, or add days to a date?
Use the date calculator: pick a start and end date to get the exact number of days between them (also shown in weeks), or enter a date plus a number of days to find a future or past date — for example, what date is 90 days from today.
How do I convert a monthly salary to hourly pay?
Multiply the monthly salary by 12 for the annual salary, divide by 52 for weekly pay, and divide the weekly pay by your working hours per week for the hourly rate. The salary calculator shows annual, monthly, weekly, daily and hourly figures together, in PKR, USD, INR, GBP or EUR.
Does this calculator work on mobile phones?
Yes — all twelve tools are fully responsive and work on phones, tablets and desktops in any modern browser. No app download is needed; just bookmark this page.
Is my data private?
Yes. All calculations happen locally in your browser using JavaScript. Nothing you type — dates, text or numbers — is sent to a server or stored anywhere.