This question already has answers here:
Large numbers erroneously rounded in JavaScript
(6 answers)
Closed 8 years ago.
I have this number in javascript - 1234567890123456789
This number is apparently a magical number, because when interpreted the lowest two digits magically turn into zeros!!!!!!! Run it through the console and you get this: 1234567890123456800
But wait - theres more. try out this number: 12345678901234568999
Console outputs 12345678901234570000
What is going on here? Have I finally lost my mind or is this some sort of cosmic joke?
Numbers in JavaScript are floating point numbers. As such, integers/numbers above a certain value are prone to precision errors, as you have experienced first hand.
Any number larger than Number.MAX_SAFE_INTEGER, or 9007199254740991, is going to experience precision issues. That is, only integers up to 15 digits are guaranteed to be exact.
Related
This question already has answers here:
Is floating point math broken?
(31 answers)
Closed 5 years ago.
Can anyone answer me why javascript adds up 1.123460 + 0.112210 as 1.2356699999999998
while no way I can come up with that result by manual calculation or by any other compilers..
Am I going crazy or javascript, cannot figure out
Its just how JavaScript and many other languages deal with floats. Rounding them to 15 decimal places. Check this How to deal with floating point number precision in JavaScript? How to deal with floating point number precision in JavaScript?
This question already has answers here:
How to deal with floating point number precision in JavaScript?
(47 answers)
Closed 6 years ago.
I am trying to use eval() for calculator i am making, but if when i try this
console.log(eval("5.2-5"));
It returns
0.20000000000000018
Why is this happening.Thank you for your time.
This is due to how Javascript handles floating point precision. Please see How to deal with floating point number precision in JavaScript? for more information
Short answer: Due to the nature of how computers process floats, this means floating point accuracy actually breaks down past a certain point. This is what you're seeing.
Javascript evaluates "5.2-2" to a floating point number, which precision is not guaranteed.
If you need a fixed precision you could use
console.log(eval("5.2-5.0").toFixed(2)):
This question already has answers here:
What is JavaScript's highest integer value that a number can go to without losing precision?
(21 answers)
Closed 29 days ago.
So, for parseInt('10152547376283911', 10) I'm expecting 10152547376283911, but I'm getting 10152547376283912.
What I'm doing wrong?
Javascript native numbers do not have enough precision (significant digits) to hold the number you are expecting. See the question What is the standard solution in JavaScript for handling big numbers (BigNum)? for suggestions on how to deal with this problem.
Depending on your application, you may actually be able to use strings instead of numbers (for example, if your number represents something like a physical part number). You would only need a bigint library if you intend to do arithmetic on your numbers.
This question already has answers here:
Is floating point math broken?
(31 answers)
Closed 9 years ago.
test there in their consoles browser
1067.11-1000 = 67.1099999999999
but the correct thing 67.11
can even test the calculator windows ..
could someone explain this to me?
Floating point numbers are stored using base2, this creates small differences like the one you demonstrate above when converting to base10. The difference will be even greater if use the following numbers: 1000000067.11 - 1000000000 = 67.1100000143. This is because the level of precision decreases as the numbers calculated increases.
Lack of precision is the main disadvantage of the float type numbers - some real numbers can only be represented approximately.
You can follow this link to learn more about representation of floating point format
This question already has answers here:
Large numbers erroneously rounded in JavaScript
(6 answers)
Closed 9 years ago.
I have a problem with javascript number. My problem is that I have a currency field in HTML and when I use javascript to calculate with another field; then if this input field has the number of digits > 15 then this is auto rounded.
You can try this in firebug. E.g:
(9999999999999999);
10000000000000000
How do I fix this?
You have a currency field that you care is rounding past 9999999999999999??
I'm impressed right there :P
It's a limitation of having large floating point numbers. There's no easy way to fix it short of getting a bigint javascript library, I'm sure there's a few out there. But honestly, why do you care?