Authoritative definitions of the International System of Units and SI prefixes.
Dedicated unit pair
Per mille to Fraction
Convert ‰ to instantly, then review the formula, assumptions, and rounding guidance.
Chemistry concentration unitsInstant result
Decimals
Formula result = input × 0.001 ÷ 1. 1 ‰ = 0.001
Common examples
One value, several units
Fraction0.001
Percent0.1 %
Parts per million1,000 ppm
Parts per billion1,000,000 ppb
Conversion table
| ‰ | |
|---|---|
| 1 ‰ | 0.001 |
| 2 ‰ | 0.002 |
| 5 ‰ | 0.005 |
| 10 ‰ | 0.01 |
| 25 ‰ | 0.025 |
| 50 ‰ | 0.05 |
| 100 ‰ | 0.1 |
Conversion chart
1 ‰0.001
5 ‰0.005
10 ‰0.01
25 ‰0.025
50 ‰0.05
Worked example
1% equals 10,000 ppm.
Unit definition
Per mille (‰) One per mille equals 0.001 fraction.
Unit history
Per mille is represented here using its modern SI definition or an internationally accepted relationship to an SI base unit.
Step by step
1. Parse the value, including fractions.
2. Convert ‰ to fraction.
3. Convert the base value to and apply your display precision.
Important
Mass/volume ppm equivalence depends on solution density.
Understand the result before using it
Per mille to Fraction converts a value measured in Per mille (‰) into the equivalent value in Fraction (). The numerical value changes because the size and definition of the selected unit changes; the underlying quantity does not.
Calculated result
The conversion follows the displayed unit relationship. Display rounding can hide additional digits, and measured inputs cannot become more accurate merely by changing units.
Formula, assumptions, and example
Formula
result = input × 0.001 ÷ 1
Assumptions
- Per mille and Fraction represent the same dilute-solution parts quantity.
- The input is expressed in ‰; the output is expressed in .
- Mass/volume ppm equivalence depends on solution density.
Worked example
1 ‰ = 0.001 . For another value, apply the same relationship and round only to the precision your source measurement supports.
When to use it
Good uses
- Read a ‰ measurement in a document that expects .
- Compare a per mille value with a value reported in fraction.
- Check the ‰-to- arithmetic before copying the result into another calculation.
Limitations
Common mistakes to avoid
- A ppm value is not automatically a mass-per-volume value; the equivalence depends on density and how concentration is defined.
- Round the output to a precision justified by the original measurement.
- Verify safety-critical, regulated, laboratory, and contractual conversions against the controlling standard.
Sources and further reading
These references explain the underlying standards or provide authoritative context. Your own contract, institution, clinician, product documentation, local code, or governing standard may be the controlling source.
Guidance on unit names, symbols, conversions, and numerical presentation.
Questions about this calculation
How do I convert Per mille to Fraction?
result = input × 0.001 ÷ 1 Using the displayed relationship, 1 ‰ equals 0.001 .
How many Fraction are in one Per mille?
One Per mille is 0.001 Fraction. The displayed digits may be rounded.
Can I reverse the ‰ to conversion?
Yes. Swap the source and target units in the converter. The reverse relationship converts back to ‰.
Is the Per mille to Fraction result exact?
The conversion follows the displayed unit relationship. Display rounding can hide additional digits, and measured inputs cannot become more accurate merely by changing units.