Incorrect Rounding with Math.pow

Incorrect Rounding with Math.pow

Question:

I have noticed that all rounding to x decimals scripts uses the following format:

tenToPower = Math.pow(10, nDecimals);newNumber = String((Math.round(nNumber * tenToPower) / tenToPower));

However, that doesn’t work with numbers like 0.5005, yet DOES work with 0.50051. Any idea why, and how to fix the script above?

Answer:

Simply put, JavaScript is good at a lot of things, but math isn’t one of them.

If you take .5005 and multiply it by 1000, you and I get 500.5. That number, rounded, is 501. When JavaScript does that same multiplication, though, it gets a product of 500.49999999. That number, rounded, is 500.

You can try this out by entering the following into the location/address bar of your browser:

javascript:alert(.5005*1000)

Unfortunately, there’s no simple workaround for this problem. You might try multiplying by another power of ten and then dividing by that on the other side.

Share the Post:
XDR solutions

The Benefits of Using XDR Solutions

May 24, 2023

Cybercriminals constantly adapt their strategies, developing newer, more powerful, and intelligent ways to attack your network. Since security professionals must innovate as well, more conventional endpoint detection solutions have evolved

AI is revolutionizing fraud detection

How AI is Revolutionizing Fraud Detection

May 23, 2023

Artificial intelligence – commonly known as AI – means a form of technology with multiple uses. As a result, it has become extremely valuable to a number of businesses across

AI innovation

Companies Leading AI Innovation in 2023

May 22, 2023

Artificial intelligence (AI) has been transforming industries and revolutionizing business operations. AI’s potential to enhance efficiency and productivity has become crucial to many businesses. As we move into 2023, several

data fivetran pricing

Fivetran Pricing Explained

May 17, 2023

One of the biggest trends of the 21st century is the massive surge in analytics. Analytics is the process of utilizing data to drive future decision-making. With so much of

kubernetes logging

Kubernetes Logging: What You Need to Know

May 16, 2023

Kubernetes from Google is one of the most popular open-source and free container management solutions made to make managing and deploying applications easier. It has a solid architecture that makes

ransomware cyber attack

Why Is Ransomware Such a Major Threat?

May 15, 2023

One of the most significant cyber threats faced by modern organizations is a ransomware attack. Ransomware attacks have grown in both sophistication and frequency over the past few years, forcing

data dictionary

Tools You Need to Make a Data Dictionary

May 12, 2023

Data dictionaries are crucial for organizations of all sizes that deal with large amounts of data. they are centralized repositories of all the data in organizations, including metadata such as

Show More