About the Online Calculator
Tezmy's Online Calculator handles everything from quick sums to scientific maths. Use the big keypad on your phone, or type straight into it on a computer and press Enter. It follows the correct order of operations, shows the answer as you type, and keeps a history you can tap to reuse. Scientific functions include powers, square roots, percentages, factorials, sine, cosine, tangent in degrees or radians, natural and base-10 logarithms, and the constants π and e.
Updated October 2026
How to use the Online Calculator
- 1Tap the keys, or type your calculation on a keyboard.
- 2See the answer preview as you type.
- 3Press = (or Enter) to confirm it and save it to history.
- 4Switch between DEG and RAD for trigonometry.
Basic and scientific in one
Use it like a normal calculator for shopping sums, bills and homework, or switch to the scientific keys for powers, roots, factorials, trigonometry and logarithms. Everything is on one screen, so there's no mode to switch and nothing to install.
Order of operations, done right
The calculator follows the standard order: brackets first, then powers, then multiplication and division, then addition and subtraction. So 2 + 3 × 4 gives 14, not 20. Use brackets to be sure: (2 + 3) × 4 gives 20. The live preview shows the answer before you press equals, which helps catch typing mistakes.
Degrees or radians?
Most everyday and school problems use degrees: sin(30) = 0.5 in DEG mode. Radians are used in higher maths, physics and programming, where sin(π/6) = 0.5 in RAD mode. If a trigonometry answer looks strange, check which mode you're in.
Handy extras
- History: tap an earlier result to use it again in a new calculation.
- Keyboard: type numbers and operators on a computer and press Enter for the result.
- Percent: 200 × 15% gives 30, handy for quick discounts and tips.
- Constants: π and e are built in to many decimal places.
Use it on any device
On phones, the big keypad is easy to tap with one hand. On a computer, type with your keyboard: numbers, + − * /, brackets and ^ for powers, then press Enter. Nothing is installed and nothing is sent anywhere, so it's quick even on a slow connection. When your sum is about a share, open the Percentage Calculator, and for working with parts of a whole use the Fraction Calculator. If you have a list of scores or prices, the Average Calculator gives the mean without any typing of plus signs.
Features
- Correct order of operations
- Powers, roots, %, factorials
- sin, cos, tan in degrees or radians
- log, ln, π and e
- Live answer preview
- History you can reuse
Frequently asked questions
Does it follow the order of operations?
Yes. Brackets come first, then powers, then multiplication and division, then addition and subtraction (BODMAS / PEMDAS). So 2 + 3 × 4 = 14.
How do percentages work?
The % key divides by 100, so 200 × 10% = 20. To add 10% to a number, type 200 × 1.1 or 200 + 200 × 10%.
Should I use DEG or RAD?
Use DEG (degrees) for everyday angles, where a full turn is 360. Use RAD (radians) for most maths and physics formulas, where a full turn is 2π.
Can I type instead of clicking?
Yes. On a computer, click the display and type, for example sqrt(2)^2 + 5!, then press Enter.
Why does 0.1 + 0.2 show exactly 0.3?
Computers store decimals in binary, which causes tiny errors like 0.30000000000000004. We round results to 12 significant digits so you see the answer you expect.
Is this calculator free to use?
Yes, completely free with no ads in the way, no sign-up and no limits. It works in any browser on phones, tablets and computers.
Does it work offline?
Once the page has loaded, the calculations run on your device, so it keeps working even if your connection drops.
How do I calculate a square root?
Tap √ and then the number, like √81 for 9. For other roots, use powers: 27^(1/3) gives the cube root, 3.