Quick answer
1% = 10,000 ppm, 1‰ = 1,000 ppm, and 1 ppm = 1,000 ppb. 250 ppm is 250,000 ppb, 0.025% or 0.25 per mille.
Pick the unit you have and enter the value. The calculator converts to ppm, ppb, percent and per mille.
How to use the PPM Converter
- Choose unit: Parts per million (ppm), Parts per billion (ppb), Parts per trillion (ppt), Percent (%) and Per mille (‰).
- Enter value (above 0).
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Unit | Choose one: Parts per million (ppm); Parts per billion (ppb); Parts per trillion (ppt); Percent (%); Per mille (‰) | Starts at Parts per million (ppm) |
| Value | A number | > 0 |
Formula and method
Formula
1% = 10,000 ppm; 1‰ = 1,000 ppm; 1 ppm = 1,000 ppb
IEEE-754 double precision; shown to at most 6 decimal places.
Dimensionless ratios on the same basis (mass or volume).
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Unit = Parts per million (ppm); Value = 250.
| Result | Value |
|---|---|
| In ppm | 250 ppm |
| Parts per billion | 250,000 |
| Percent | 0.025% |
| Per mille | 0.25 |
Example 2
Inputs: Unit = Percent (%); Value = 0.5.
| Result | Value |
|---|---|
| In ppm | 5,000 ppm |
| Parts per billion | 5,000,000 |
| Percent | 0.5% |
| Per mille | 5 |
Example 3
Inputs: Unit = Parts per billion (ppb); Value = 1500.
| Result | Value |
|---|---|
| In ppm | 1.5 ppm |
| Parts per billion | 1,500 |
| Percent | 0.00015% |
| Per mille | 0.0015 |
The first line is the headline result (in ppm). Below it the pPM Converter lists parts per billion, percent and per mille, which describe the same case from other angles. IEEE-754 double precision; shown to at most 6 decimal places.
In water
For dilute aqueous solutions, 1 ppm is about 1 mg per litre, since a litre of water weighs about 1 kg. For gases ppm is usually by volume, and for soil and food it is mg per kg.
Percent conversions
Move the decimal four places: 0.025% × 10,000 = 250 ppm. 5,000 ppm is 0.5%.
How the result changes with value
Holding every other input at the first worked example, this table changes only value. It shows how sensitive the answer is to that one value; each row was produced by running this calculator.
| Value | In ppm | Parts per billion | Percent |
|---|---|---|---|
| 125 | 125 ppm | 125,000 | 0.0125% |
| 250 | 250 ppm | 250,000 | 0.025% |
| 500 | 500 ppm | 500,000 | 0.05% |
| 1000 | 1,000 ppm | 1,000,000 | 0.1% |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Value: entering "0" shows "Value must be greater than 0." beside that field and no result.
Choosing between the PPM Converter and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [mg/L to ppm Converter](/science/mgl-to-ppm/) | concentration and solution density | Concentration |
| [ppb to ppm Converter](/science/ppb-to-ppm/) | convert and value | Concentration |
| [Powerball Odds Calculator](/other/powerball/) | white balls matched and powerball matched? | Odds |
| [Nether Portal Coordinates Calculator](/other/nether-portal/) | i know coordinates in the, x and z | Matching coordinates (X, Z) |
| [D&D Point Buy Calculator](/other/point-buy/) | sTR score, dEX score and cON score | Points spent |
Assumptions and limitations
- Short-scale billion (10⁹)
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for value to confirm this.
Frequently asked questions
Is ppm the same as mg/L?
For dilute water solutions, yes.
What is ppb?
Parts per billion, 1/1000 of a ppm.
How many ppm is 1%?
1% is 10,000 ppm, since a percent is one part in a hundred.
What does the PPM Converter calculate?
Convert between ppm, ppb, ppt, percent and per mille. It returns In ppm, Parts per billion, Percent and Per mille.
What formula does the PPM Converter use?
1% = 10,000 ppm; 1‰ = 1,000 ppm; 1 ppm = 1,000 ppb. Dimensionless ratios on the same basis (mass or volume).
What do I need to enter in the pPM Converter?
You enter Unit and Value.
How is the result rounded or limited?
IEEE-754 double precision; shown to at most 6 decimal places. Short-scale billion (10⁹).
What does the “Unit” option change?
It sets how the pPM is worked out. The choices are Parts per million (ppm), Parts per billion (ppb), Parts per trillion (ppt), Percent (%) and Per mille (‰).
What is an example of a pPM result?
With unit Parts per million (ppm) and value 250, the in ppm is 250 ppm.
Where does the method come from?
The method follows: Definitions of ppm, ppb and ppt (short scale).
Related calculators
- K/D Ratio Calculator — Kill/death ratio.
Sources
- Definitions of ppm, ppb and ppt (short scale)
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.