This question already has answers here:
Javascript float subtract
(6 answers)
How to deal with floating point number precision in JavaScript?
(47 answers)
Closed 6 years ago.
So I am having issues with numbers:
I have a item, with a price of 483.65. I want to multiply this by 7. Expected result should be:
3385.55
However, Javascript reds this as:
3385.5499999999997
The number in the database is stored as a Float.
Here are screenshots to explain the situation better:
What am I missing?
be careful with floating point math operations.
thats because of floating point standard used by js vm.
one trick I found to fix it without external libs is to multiple by 1k and than divid by 1k.
483.65 * 1000 * 7 / 1000
strange but always works.
Related
This question already has answers here:
Is floating point math broken?
(31 answers)
Closed 3 years ago.
I have big numbers coming from the backend service in my JS application. I don't want to lose any of the digits after the decimal place.
However, when a number like 999999999999999.99 is assigned to a variable in JS, it rounds it to 1000000000000000 and 99999999999999.99 turns to 99999999999999.98.
Both numbers are within the limits. i.e. less than Number.MAX_SAFE_INTEGER
See the above in action in the screenshot below:
Can anybody shed some light on it, please?
MAX_SAFE_INTEGER only guarantees precision for integers below it, not decimals.
In fact there are no decimals in Javascript only floating point numbers. When you try to represent a number with too much precision it'll just be rounded to the nearest 64 bit floating point number.
If you actually want decimals you will need to use a decimal library like decimal.js or you could write your own.
This question already has answers here:
Large numbers erroneously rounded in JavaScript
(6 answers)
Closed 5 years ago.
I'm new in developing javascript apps, i have a doubt about a behaviour that i'm going to try to explain.
If i execute:
Number(5555555555555555);
Result: 5555555555555555
But if i execute:
Number(55555555555555555);
Result: 55555555555555550
Anybody can explain to me what is the reason of this? Thanks!!
If you need to work with such big numbers I would suggest you use some of the big integer libraries such as this. The reason this happens as far as I know is the way processors and memory work. It's no related to some "bug" in JS.
Integers (numbers without a period or exponent notation) are accurate up to 15 digits. Javacript simply adds zeros to keep the number accurate in terms of its digit length.
Documentation
This question already has answers here:
Is floating point math broken?
(31 answers)
Closed 6 years ago.
Is there a solution to the infamous floating point math error in JavaScript due to the 64-bit floating point representation?
Is floating point math broken?
Im trying to make a math intensive application based on JavaScript, however, due to this error in JavaScript, it always results in inaccurate output.
For ex.:
0.1 + 0.2 = 0.30000000000000004
whereas the expected is
0.1 + 0.2 = 0.3
I wonder how the financial organizations like (PayPal) are still up with there javascript applications.
The "solution" to the (non-)error is to ignore it, and ensure that you use an appropriate function, i.e. toFixed(n), to present the number with the desired number of decimal places.
It's important to know the difference between the internal representation of a value, and how to present that value to the end user.
You can use https://github.com/ekg/fraction.js library for the intermediate values and convert the final result back to decimal value to minimize error.
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
Is JavaScript’s Math broken?
Funny question, but why at 16.1 javascript become "crazy"? :)
Code :
var value1=16.1;
var value2=16.2;
console.log(value1 * 1000);
console.log(value2 * 1000);
Output :
16100.000000000002
16200
Why?
That's because javascript casts everything to a double internally. As a result, all calculations pick up some noise due to floating point inaccuracy: Floating point inaccuracy examples
One way to fix this issue, is to just round down to the nearest int after all intermediate calculations.
Answer Copy From Here
It's not a javascript problem, it's a problem related to any programming language using floating point numbers, see
Is floating point math broken?
for explanation of the root problem and for some useful workarounds too.
This question already has answers here:
Closed 11 years ago.
Possible Duplicate:
Is JavaScript's Math broken?
I've some problems with javascript.
If I do this:
alert(6.000 * 1.050);
I expect 6.3, but I get 6.30000001
can anybody help me ? or explain why this happens?
Here you can simple use the method toFixed() in java-script
alert(parseFloat(6.000 * 1.050).toFixed(1));
They're called floats, and sometimes have a little bit of inaccuracy.
http://en.wikipedia.org/wiki/Floating_point#Accuracy_proble
Standard problem; decimals can't be stored with infinite precision in general, so most programming languages have data types that approximates them and show a rounded version. Problem is that multiplication or subtraction can cause the inaccuracies to show.
In the end, you'll just have to round probably.