Scientific Calculator - Free online Math

① 表达式求值

表达式（支持键盘输入，Enter 计算，Esc 清空）

三角函数角度单位

结果保留位数

三个约定：「%」就是把数字除以 100，所以 200×10% = 20，要「涨 10%」请写 200*(1+10%)；相邻的量会自动相乘，2pi、3(4+1)、(2)(3) 都能算；函数括号可省，sin30 等同于 sin(30)。数字里的千分位逗号可用，如 1,000/8。

② 历史记录（点击任意一条可回到输入框）

还没有计算记录，算一次就会出现在这里

③ 一批表达式一起算

一行一个表达式，自动跳过空行

批量计算沿用 ① 里的角度单位与保留位数设置；Ans 在批量模式下取上一次单条计算的结果。每行必须是完整表达式，不能只写运算符。

About this tool

A basic calculator cannot evaluate 12!/(5!*7!), and running eval on user input is not acceptable. This tool tokenises the expression, converts it to postfix and evaluates it, so you get exactly what you typed, with every rule stated:

Full expressions: arithmetic, parentheses, powers, factorials, percentages and remainders can be mixed; 2+3*4 is 14, (2+3)*4 is 20 and (2+3)*sqrt(16)/2^3 is 2.5
Scientific and engineering forms: 1e3+1 is 1001, 2E-2 is 0.02 and 1,000,000/8/7 understands thousands separators and gives 17857.1428571
Optional parentheses and multiplication signs: 2pi is 6.28318530718, 3(4+1) is 15, sin30 equals sin(30), √9 is 3 and ∛(-27) is -3
DEG and RAD: in degrees sin(30) is 0.5 and acos(0.5) is 60; in radians sin(30) is -0.988031624093, and inverse trig output follows the mode
Several views of the result: grouped form, full double-precision value, scientific notation, integer part, decimal places, three rounding modes and a reduced fraction approximation
Ans and memory: Ans recalls the last result, MS stores, MR recalls and MC clears; continuing from the previous answer is one click
History: the last 20 expressions and results, and clicking one loads it back for editing
Batch evaluation: one expression per line; a bad line does not stop the others and its error is shown beside it
Explained errors: unclosed parentheses report how many closing brackets are missing, and 1/0, √-4, ln(0), tan(90), 171! and (-8)^0.5 each get a specific message

When to use it

Write a long calculation in one line, such as a combination, a geometric series sum or a compound interest total that chained key presses cannot handle
Check a formula by hand and verify it without precedence mistakes
Evaluate a pasted column of expressions from a spreadsheet or notes
Teach right-associative powers, the precedence of unary minus and roots, and the difference between degrees and radians
Engineering and statistics with hyperbolic functions, base-2 logs, remainders and factorials

Supported syntax

Input	Meaning	Result
2+3*4	Multiplication first	14
2^10 and 2**10	Power, both spellings	1024
2^3^2	Right-associative, so 3^2 first	512, not 64
-2^2	Power binds tighter than unary minus	-4; write (-2)^2 for 4
5! and fact(5)	Factorial	120
10% and 200*(1+10%)	Percent means divide by 100	0.1 and 220
100 mod 7	Remainder	2
12!/(5!*7!)	Combination written directly	792
3(4+1), 2pi, (2)(3)	Adjacent values multiply	15, 6.28318530718, 6
1,000/8	Thousands separator	125
sin30 + 1	A function without brackets takes only the next value	1.5, not sin(31)
ans*2	Recall the last result	42 when the last answer was 21

Precedence, highest first

Parentheses ( ): the direct way to change precedence; unclosed brackets report how many are missing
Postfix ! %: bound to the preceding value, so 2^3! is 2^6 = 64
Power ^: right-associative and tighter than unary minus
Unary signs -3 +5: can repeat, so 3 - -2 is 5
Multiply, divide, remainder * / mod: includes implicit multiplication and is left-associative
Add and subtract + -: lowest, left-associative, so 100-20-30 is 50

Functions and constants

Group	Names	Checked example
Trig and inverse trig	sin cos tan asin acos atan	DEG: `cos(60)+sin(30)` = 1, `asin(0.5)` = 30
Hyperbolic	sinh cosh tanh	`cosh(0)` = 1, `sinh(0)` = 0
Powers and roots	^ ** sqrt √ cbrt ∛	`9^(1/2)` = 3, `sqrt(144)+3^2` = 21
Logs and exponentials	ln log lg log10 log2 exp	`log(1000)+ln(e)` = 4, `log2(1024)` = 10
Rounding and sign	abs round floor ceil sign	`round(2.5)+floor(2.5)+ceil(2.5)` = 8
Factorial and remainder	! fact mod	`5!+3!` = 126, `10 mod 3` = 1
Angle conversion	degrees radians	`degrees(pi/3)` = 60, `radians(180)` = pi
Constants	pi π e phi φ tau	π = 3.14159265359, e = 2.71828182846, φ = 1.61803398875, tau = 6.28318530718

Common questions

Why is -2^2 equal to -4?In mathematics minus x squared means the negative of x squared, so the power goes first. Use (-2)^2 for 4. The same rule makes 2^3^2 equal 512 rather than 64
Why does the result show 0.3 while the raw value is 0.30000000000000004?That is the inherent representation error of double-precision floating point. Automatic mode rounds to 12 significant figures to hide the noise; sqrt(2)*sqrt(8) shows 4 while the raw value is 4.000000000000001 for the same reason. Check the raw value row to see the real error
Degrees or radians?Degrees by default, so sin(30) is 0.5. In radians 30 means 30 radians and sin(30) is -0.988031624093. Inverse trig output follows the mode, so acos(0.5) is 60 in degrees. The degrees and radians functions ignore the switch and always convert by the radian definition
Why is sin(pi) not zero?The result is 1.224647e-16. Pi can only be stored approximately, and the rate of change of sine near pi is about -1, so input error becomes output error almost unchanged. Test against a tolerance instead of expecting an exact integer
How large a factorial can it handle?170! is 7.257416e+306, close to the double limit of about 1.8e308, and 171! reports overflow. Fractional and negative factorials are not supported because they need the Gamma function and complex numbers. Integer ratios such as 12!/(5!*7!) = 792 cancel safely before overflow
What does the percent sign mean?Divide by 100: 10% is 0.1 and 200*10% is 20. For a 10 percent increase write 200*(1+10%) = 220. A monthly 10 percent rise over a year totals (1+10%)^12-1 = 2.13842837672, or 213.84 percent
Does it execute the code I type?No. The input is tokenised, implicit multiplication is inserted, a shunting-yard pass produces postfix, and that is evaluated step by step. There is no eval and no dynamic function construction; letters are only accepted as registered function names and constants, and anything else is rejected with a position
What is not supported?Multi-argument functions (use log2(8) or log(8)/log(2)), variables and user-defined functions, complex numbers and infinity symbols, and summation or product notation. 1e3 is read as 1000, so write 1*e*3 for 1 times e times 3

Related tools: use the fraction calculator to turn a result back into an exact fraction, the percentage calculator for shares and changes, the compound interest calculator to expand a final value into a year-by-year table, and the unit converter for units. Expressions and results stay in the browser and are never uploaded.