gallons to ppm Converter
Dosing a tank or pool is done in grams and gallons. This tool turns that mix into ppm.
Quick answer: Multiply the grams by 1,000, then divide by the gallons times 3.7854. For example, 10 g in 1,000 gallons is 2.642 ppm, 5 g in 250 gallons is 5.283 ppm and 100 g in 10,000 gallons is 2.642 ppm.
The grams per gallons to ppm formula
One US gallon is 3.785411784 liters (Wikipedia: Gallon).
In water, 1 ppm is 1 mg per liter (Wikipedia: Parts-per notation), so ppm equals the mg divided by the liters.
Take 10 g in 1,000 gallons. 10 × 1000 ÷ (1,000 × 3.7854) gives 2.642 ppm.
Take 5 g in 250 gallons. 5 × 1000 ÷ (250 × 3.7854) gives 5.283 ppm.
grams per gallons to ppm step by step
Enter the grams of substance.
Enter the US gallons of water.
ppm is the result. The last column gives ppm per 1 g.
How to convert grams per gallons to ppm step by step
- Enter the grams of substance.
- Enter the US gallons of water.
- Read the result in ppm.
- Check it against the quick table.
Example 1: 10 g in 1,000 gallons
- Start with 10 g in 1,000 gallons.
- 10 × 1000 ÷ (1,000 × 3.7854) = 2.642.
- The concentration is 2.642 ppm.
10 g in 1,000 gallons = 2.642 ppm
Example 2: 5 g in 250 gallons
- Start with 5 g in 250 gallons.
- 5 × 1000 ÷ (250 × 3.7854) = 5.283.
- The concentration is 5.283 ppm.
5 g in 250 gallons = 5.283 ppm
Example 3: 100 g in 10,000 gallons
- Start with 100 g in 10,000 gallons.
- 100 × 1000 ÷ (10,000 × 3.7854) = 2.642.
- The concentration is 2.642 ppm.
100 g in 10,000 gallons = 2.642 ppm
The sum assumes the water weighs 1 kg per liter and the dose adds little volume.
grams per gallons to ppm conversion table
| Substance and water | ppm | ppm per 1 g |
|---|---|---|
| 10 g in 1,000 gallons | 2.642 ppm | 0.2642 ppm per 1 g |
| 1 g in 100 gallons | 2.642 ppm | 2.642 ppm per 1 g |
| 5 g in 250 gallons | 5.283 ppm | 1.057 ppm per 1 g |
| 20 g in 500 gallons | 10.567 ppm | 0.5283 ppm per 1 g |
| 100 g in 10,000 gallons | 2.642 ppm | 0.0264 ppm per 1 g |
| 2 g in 50 gallons | 10.567 ppm | 5.283 ppm per 1 g |
| 50 g in 5,000 gallons | 2.642 ppm | 0.0528 ppm per 1 g |
| 0.5 g in 10 gallons | 13.209 ppm | 26.417 ppm per 1 g |
The highlighted row is the default of the calculator. The last column gives ppm per 1 g.
A quick mental shortcut for grams per gallons to ppm
A gram in 264 gallons is about 1 ppm.
So 10 g in 1,000 gal is about 2.6 ppm.
Why gallons become liters
A ppm in water is mg per liter.
So the gallons must first become liters.
US and UK gallons
A UK gallon is bigger than a US gallon.
This page uses the US gallon, so convert first if you use the UK one (Wikipedia: Gallon).
Worked example: 10 g in 1,000 gallons
10 g in 1,000 gallons gives 2.6417 ppm.
The same inputs give 0.26417 ppm per 1 g in the last column.
Worked example: 5 g in 250 gallons
5 g in 250 gallons gives 5.2834 ppm.
The same inputs give 1.0567 ppm per 1 g in the last column.
Worked example: 100 g in 10,000 gallons
100 g in 10,000 gallons gives 2.6417 ppm.
The same inputs give 0.026417 ppm per 1 g in the last column.
A pool example
Add 100 g to 10,000 gal of water.
That is 2.6417 ppm.
A small tank
Add 5 g to 250 gal of water.
That is 5.2834 ppm.
Going the other way
To go back, multiply the ppm by the gallons and by 3.7854, then divide by 1,000.
So 2.6417 ppm for 10 g in 1,000 gallons goes back to 10 g.
Check your answer
Reverse the answer with the back formula.
You should land on 10 g for 10 g in 1,000 gallons.
Quick conversion answers
| Conversion | Result |
|---|---|
| 1 g in 100 gallons | 2.642 ppm |
| 5 g in 250 gallons | 5.283 ppm |
| 20 g in 500 gallons | 10.567 ppm |
| 100 g in 10,000 gallons | 2.642 ppm |
| 2 g in 50 gallons | 10.567 ppm |
| 50 g in 5,000 gallons | 2.642 ppm |
Where this conversion is used
Pool and pond owners dose chemicals.
Aquarium keepers add minerals.
Students practise unit sums.
Common mistakes to avoid
- Using US and UK gallons together. This page uses the US gallon of 3.785 L.
- Using it for non-water liquids. The answer assumes the liquid weighs about 1 kg per liter.
- Mixing up the direction. Here 1 g in 100 gallons is 2.642 ppm, so a correct answer comes out bigger than the number you start with.
- Rounding too early. The answer for 20 g in 500 gallons is 10.567 ppm. Cut it to 11 ppm and you are off by about 4.1 percent, and the gap grows if you reuse it.
Related converters
Example: 5 g in 250 gallons
5 g in 250 gallons gives 5.2834 ppm.
The same inputs give 1.0567 ppm per 1 g in the last column.
Example: 20 g in 500 gallons
20 g in 500 gallons gives 10.567 ppm.
The same inputs give 0.52834 ppm per 1 g in the last column.
Frequently asked questions
How do I find ppm?
ppm = grams × 1,000 ÷ (gallons × 3.7854).
What is the answer for 10 g in 1,000 gallons?
2.6417 ppm.
What is the answer for 5 g in 250 gallons?
5.2834 ppm.
How many ppm is 1 g in 1 gallon?
About 264 ppm.
Does it work for liquids other than water?
Only roughly. It assumes 1 kg per liter.
Is this the US or UK gallon?
The US gallon of 3.7854 L.
Sources
- Wikipedia: Parts-per notation (en.wikipedia.org)
- Wikipedia: Gallon (en.wikipedia.org)
