A scientific calculator that works anywhere
This free online scientific calculator gives you the functions of a school or college calculator on any phone, tablet or computer. There is nothing to install. Tap the buttons or type with your keyboard, and a live preview shows the answer before you even press equals.
Functions included:
- Basic math: add, subtract, multiply, divide and percentages
- Powers and roots:
x^yand square root (√) - Trigonometry: sin, cos and tan, plus inverse sin⁻¹, cos⁻¹ and tan⁻¹
- Logarithms: log (base 10) and ln (natural log)
- Factorial (n!) for whole numbers
- Constants: π (pi) and e
- Ans to reuse your last answer, plus a full history list
- DEG and RAD modes for angles
How to use the calculator
- Choose DEG for degrees (most school problems) or RAD for radians.
- Enter your expression with the buttons or keyboard, for example
2^10,sqrt(144)orsin(30). - Press = or Enter. The result appears and the calculation is saved to the history.
- Press AC or Escape to clear.
You can write multiplication without a sign in many cases, such as 2π or 3(4+5).
Order of operations
The calculator follows the standard order of operations: brackets first, then powers, then multiplication and division, then addition and subtraction. That means 2 + 3 × 4 equals 14, not 20. Powers are worked out from right to left, so 2^3^2 equals 2^9 = 512. A negative sign before a power applies after the power, so -2^2 equals -4. If you are unsure, add brackets. The rules are explained well on Wikipedia's order of operations page.
Tips for trigonometry
The most common mistake is using the wrong angle mode. sin(30) equals 0.5 in DEG mode but -0.988 in RAD mode. Values like cos(90) are rounded to exactly 0 so you do not see tiny floating-point leftovers. tan(90) in degrees is undefined, and the calculator tells you so instead of showing a huge number.
More calculators for students
Work out exam marks with the Percentage Calculator, find your grade point average with the GPA Calculator, and convert units for physics homework with the Unit Converter. See all our free calculators.
Functions and keys explained
| Key | What it does | Example |
|---|---|---|
sin, cos, tan | Trigonometric functions | sin(30) = 0.5 in degree mode |
asin, acos, atan | Inverse trigonometry, returns an angle | asin(0.5) = 30 in degree mode |
log | Logarithm base 10 | log(1000) = 3 |
ln | Natural logarithm, base e | ln(e) = 1 |
√ | Square root | √(144) = 12 |
x^y | Power | 2^10 = 1024 |
! | Factorial | 5! = 120 |
π, e | Constants | π ≈ 3.14159, e ≈ 2.71828 |
% | Percent | 50% = 0.5 |
Degrees or radians?
Angles can be measured in degrees (a full circle is 360) or radians (a full circle is 2π). School geometry and most everyday problems use degrees. Calculus, physics formulas and most programming languages use radians. If sin(90) does not give 1, you are probably in radian mode. To convert: radians = degrees x π / 180.
Worked examples
Compound growth. Rs 100,000 growing at 12 percent a year for 5 years: 100000 * 1.12^5 = about 176,234.
Hypotenuse of a triangle. Sides 6 and 8: √(6^2 + 8^2) = 10.
Height using an angle. You stand 20 metres from a tower and look up at 35 degrees: 20 * tan(35) = about 14 metres (plus your eye height).
Scientific notation. The speed of light is about 3 x 10^8 m/s. Type 3 * 10^8.
Average of several numbers. (72 + 85 + 91 + 66) / 4 = 78.5. Always use brackets so the sum happens before the division.
Why this calculator is safe and accurate
Many simple web calculators use a programming shortcut called eval that can run unexpected code. This calculator uses its own expression parser that only understands numbers, operators and the listed functions. It follows the standard order of operations and handles nested brackets. Results use normal double-precision floating point, which is accurate to about 15 significant digits, the same as most handheld and phone calculators. Very small rounding effects, like 0.1 + 0.2 showing 0.30000000000000004 in some systems, are tidied for display.
Tips for exams and homework
- Write the full expression with brackets before you start typing.
- Check the angle mode before any trigonometry question.
- Estimate the answer roughly first; if the calculator result is far off, you probably typed something wrong.
- For percentages, the dedicated Percentage Calculator is quicker, and for grades use the GPA Calculator. For unit problems, the Unit Converter saves time.
For background on the maths, Khan Academy has free lessons on trigonometry and logarithms.
Common calculator mistakes and how to avoid them
Even with a good calculator, a few mistakes come up again and again:
- Missing brackets. Typing
10 + 20 / 2gives 20, not 15, because division happens first. Write(10 + 20) / 2when you want the average. - Negative numbers and powers.
-3^2is read as -(3^2) = -9. If you want 9, type(-3)^2. - Wrong angle mode. If trigonometry answers look strange, check whether you are in degrees or radians.
- Percent confusion.
200 * 15%gives 30, which is 15 percent of 200. For other percentage questions, the Percentage Calculator is clearer. - Rounding too early. Keep full precision until the final step, then round the answer.
Taking ten seconds to check the expression on screen before pressing equals prevents most errors, especially in exams and when working with money.
Frequently Asked Questions
Is this calculator allowed in exams?
Online calculators are usually not allowed in exams. Use it for homework, study and practice.
How accurate are the answers?
Results are shown to about 12 significant digits, which is more than most handheld calculators display.
Why does log give a different answer than ln?
log uses base 10 and ln uses base e (about 2.718). For example, log(100) = 2 while ln(100) is about 4.605.
Does it work offline?
Once the page has loaded, the calculator keeps working even if your connection drops.
Can I use the keyboard?
Yes. You can type numbers and operators on your keyboard and press Enter to calculate.
What is the largest number it can handle?
About 1.8 x 10^308. Larger results, such as 200!, show as infinity.
Does it support fractions?
Type fractions as division, for example 3/4. The answer is shown as a decimal.
Last updated: October 25, 2026