Scientific Calculator

Written byOleh Soloninupdated 5 October 2026

Expression

You can type 2π, sin30, 5! and leave brackets open at the end; they close themselves.

Angles

Calculator keypad

sin(30) + sqrt(16)

Result

Result4.5
How the expression was readsin(30°) + √(16) = 4.5
NoteAngles are in degrees: sin(30) = 0.5.

Type the whole expression and see exactly how it was read

Free online scientific calculator: sin, cos and tan in degrees or radians, log and ln, powers, roots and factorials. Type the whole expression with brackets and see how it was read.

A scientific calculator adds the functions a basic one lacks: trigonometry, logarithms, powers and roots, factorials, and the constants π and e. Here you type the expression as you would write it on paper rather than pressing one key at a time, so a long calculation stays in view and a typo can be fixed without starting over.

Under the answer the calculator shows how it read your input: where it put a multiplication sign, which brackets it closed and whether angles were taken in degrees. If sin 30 did not come out as 0.5, that line tells you why.

How to use

Type an expression in the box or build it with the buttons below, for example sin(30) + sqrt(16).
Choose whether angles are in degrees, as in most geometry problems, or in radians.
Read the result and the line showing how the expression was read. The = button puts the answer back in the box so you can keep going.

Functions and how to type them

Function names follow the usual calculator and programming spellings — sin, tan, asin, log — and the textbook forms tg, ctg and arctan work too. A plain number does not need brackets: sin30 and log100 are understood. The multiplication sign before a bracket, a function or π is optional as well, so 2π means 2 × π.

A logarithm to any base is a ratio of natural logs: log₃81 = ln(81) / ln(3) = 4. A root of any degree is a fractional power: the fourth root of 81 is 81^(1/4), which is 3.

Results worked out with this calculator, angles in degrees.
Operation	Type	Example	Result
Add and subtract	+ -	7 - 2 + 5	10
Multiply and divide	* /	12 / 3 * 2	8
Power	^	2^10	1,024
Square	^2 or ²	3² + 4²	25
Square root	sqrt() or √	sqrt(144)	12
Cube root	cbrt()	cbrt(27)	3
nth root	x^(1/n)	8^(1/3)	2
Sine and cosine	sin(), cos()	sin(30)	0.5
Tangent and cotangent	tan(), cot()	tan(45)	1
Inverse functions	asin(), acos(), atan()	asin(0.5)	30°
Natural log	ln()	ln(e^2)	2
Common log (base 10)	log()	log(1000)	3
Binary log	log2()	log2(1024)	10
Factorial	!	5!	120
Absolute value	abs()	abs(-7)	7
π and e	pi or π, e	2π	6.28318530718

Degrees or radians

Angles are measured in degrees, where a full turn is 360°, or in radians, where a full turn is 2π ≈ 6.283. To convert, radians = degrees × π / 180, so 180° is π and 90° is π/2.

The same input gives different answers in the two modes. sin(30) is 0.5 in degrees but −0.988 in radians, because 30 radians is almost five full turns. If a sine or cosine contains π while degrees are selected, the calculator warns you, since π almost always signals radians.

Values match the calculator's output; decimals rounded to four places.
Angle	Radians	sin	cos	tan
0°	0	0	1	0
30°	π/6	1/2 = 0.5	√3/2 ≈ 0.8660	√3/3 ≈ 0.5774
45°	π/4	√2/2 ≈ 0.7071	√2/2 ≈ 0.7071	1
60°	π/3	√3/2 ≈ 0.8660	1/2 = 0.5	√3 ≈ 1.7321
90°	π/2	1	0	undefined
180°	π	0	−1	0

Order of operations

Brackets come first, then functions and factorials, then powers, then multiplication and division, and finally addition and subtraction. Operations on the same level run left to right, except powers, which run right to left.

A leading minus is weaker than a power: -2^2 is read as −(2²) and equals −4. To raise a negative number to a power, put it in brackets: (-2)^2 = 4.

Input	How it is worked out	Result
2 + 3 * 4	multiplication before addition	14
(2 + 3) * 4	brackets first	20
12 / 3 * 2	left to right: 4 × 2	8
2^3^2	right to left: 2^9	512
-2^2	power before the minus	−4
(-2)^2	minus inside the brackets	4

Precision and very large numbers

Results are shown to 12 significant figures: 1/3 appears as 0.333333333333 and π as 3.14159265359. Very large and very small numbers switch to powers of ten, so 2^100 = 1.26765060023 × 10³⁰.

Computers store decimals in binary, where 0.1 + 0.2 comes out as 0.30000000000000004; the calculator drops that tail and shows 0.3. Factorials go up to 170!, because 171! is larger than the biggest number that binary format can hold.

What this calculator shows

The result to 12 significant figures, with powers of ten for very large and very small numbers
How the input was read: multiplication signs, closed brackets, degree signs on angles
A plain reason when something cannot be calculated: division by zero, the log of a negative number, tan 90°

What to keep in mind

Angles default to degrees; asin, acos and atan return degrees too, and acot returns an angle between 0 and 180°.
The calculator does not raise a negative number to a fractional power, so (-8)^(1/3) returns no result even though the cube root of −8 exists; use cbrt(-8) = −2 instead.
On this page a comma followed by three digits groups thousands, so 1,000 is one thousand.
log without a base is the common logarithm, base 10.

FAQs

How do I calculate sine in degrees?

Leave Angles set to degrees and type sin(30); the answer is 0.5. In radians the same input gives −0.988, because 30 is then taken as 30 radians.

What is the difference between log and ln?

log is the common logarithm, base 10: log(1000) = 3. ln is the natural logarithm, base e ≈ 2.718: ln(e²) = 2. log2 gives the binary logarithm, so log2(1024) = 10.

How do I take a log to base 3 or base 5?

Divide two natural logs: log_a(b) = ln(b) / ln(a). For example, log₃81 = ln(81) / ln(3) = 4. For more work with logarithms there is a separate log calculator.

How do I find a cube root or an nth root?

Use cbrt(27) = 3 for a cube root; it also works for negative numbers, so cbrt(-8) = −2. Any other root is a fractional power: the fourth root of 81 is 81^(1/4) = 3.

Why does tan 90° give an error?

Tangent is sine divided by cosine, and cos 90° = 0. Division by zero has no value, so tan 90° and tan 270° are undefined. The same goes for cot 0° and cot 180°.

What does the "How the expression was read" line mean?

It is your input written out in full, with explicit multiplication signs, closed brackets and degree signs on angles. It shows, for instance, that 2π was read as 2 × π and -2^2 as −(2^2) = −4.

Does it work on a phone?

Yes. The buttons under the box cover sin, cos, tan, ln, log, roots, powers, brackets and π. The = button puts the answer back into the box, and brackets left open at the end are closed for you.

Worked example

Height of a building from an angle

Input: 20 * tan(35): you stand 20 m from the building and see the roof edge at 35°

Output: About 14 m (14.0041507642)

Note: The tangent of an angle is the opposite side over the adjacent side, so height = distance × tan(angle). Add your eye height, because the angle is measured from eye level.

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