CODEWITHSUNDEEP
javascriptfloating-pointparsefloat
Aarti Jain
Aarti Jain

Reputation:

ParseFloat function in JavaScript

When I am adding two textbox values that are 1.001 and 0.001 and then I do a parseFloat I get 1.0019999999. I want it 1.002 . Can you help me?

Upvotes: 11

Views: 18790

Answers (5)

17 of 26
17 of 26

Reputation: 27382

The Javascript Number class has a toFixed() function that will get you what you want.

So you could do parseFloat("1.0019999").toFixed(3) and that would give you 1.002.

The parameter (3 in this case) is the number of digits to show after the decimal point

Upvotes: 27

Lorenzo Polidori
Lorenzo Polidori

Reputation: 10512

The javascript methods Number.toFixed() and Number.toPrecision() can help here, but they return a String. A possible solution is as follows:

var x = parseFloat(parseFloat("1.0019999999").toPrecision(3));

Upvotes: 6

user19745
user19745

Reputation: 3649

If you want to a quick fix you can round to the nearest thousandth

Math.round((1.001+0.001)*1000)/1000

Upvotes: 0

SpoonMeiser
SpoonMeiser

Reputation: 20397

0.002 cannot be accurately represented as a base 2 number. Similar to the way that 1/3 can't be represented in base 10.

1/3 = 0.33333... recuring. To represent the number accurately in base 10, you would need an infinite number of decimal digits.

0.002 is a number that can be accurately represented in base 10 (as we see here), but not in base 2, as used by computers. To represent this number accurately, would take an infinite number of binary digits.

Upvotes: 10

Burkhard
Burkhard

Reputation: 14738

This is a known problem: see accuraty problem and the minimisation of the accuracy problem: minimisation

Upvotes: 6

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