Deciphering the Unit: What's the Difference Between Percent and Permille?

We all know "percent" (%) means "per 100." But have you ever seen the symbol ‰? That is the permille (or per mil) symbol, and it means "per 1,000."

Why Use Permille Instead of Percent?

Sometimes, percentages are just too small to be practical. If something occurs 0.05 times per 100, it's often clearer to say it occurs 0.5 times per 1,000.

Common Uses for Permille

• Demographics: Birth and death rates are usually expressed as permille (e.g., 12 births per 1,000 people).
• Oceanography: Salinity levels in seawater are measured in permille (the average is 35‰).
• Blood Alcohol Content (BAC): In many countries, your legal limit for driving is measured in permille.
• Geography: The slope of a road or railway is often given in permille.

Converting Between the Two

Converting is simple:

• Percent to Permille: Multiply by 10. (1% = 10‰)
• Permille to Percent: Divide by 10. (1‰ = 0.1%)

Why It Matters

Misreading these symbols can lead to a tenfold error in your data! When working with very small ratios or high-precision engineering data, always check if the symbol has one zero at the bottom (%) or two (‰).

Precision with vPercentage

While we focus on percentages, the same logic of ratios and proportions applies everywhere. Our Basic Percentage Calculator can handle the high-precision calculations needed to ensure your ratios are always accurate.