Calculate grams of a substance from total mixture mass and mass percent, or find the missing total mass or percent using common weight units.
| Percent to Grams | Grams to Percent |
|---|---|
| 0.1% of 100 g = 0.1 g | 0.2 g in 100 g = 0.2% |
| 0.25% of 100 g = 0.25 g | 0.4 g in 100 g = 0.4% |
| 0.5% of 100 g = 0.5 g | 0.8 g in 100 g = 0.8% |
| 1% of 100 g = 1 g | 3 g in 100 g = 3% |
| 2% of 100 g = 2 g | 6 g in 100 g = 6% |
| 5% of 100 g = 5 g | 15 g in 100 g = 15% |
| 10% of 100 g = 10 g | 25 g in 100 g = 25% |
| 25% of 100 g = 25 g | 50 g in 100 g = 50% |
| 50% of 100 g = 50 g | 75 g in 100 g = 75% |
| 75% of 100 g = 75 g | 100 g in 100 g = 100% |
| Formula: grams = total x % / 100. Assumes total mixture = 100 g. | |
| Percent to Grams | Grams to Percent |
|---|---|
| 10% of 1 kg = 100 g | 1 g in 1 kg = 0.1% |
| 12.5% of 1 kg = 125 g | 2.5 g in 1 kg = 0.25% |
| 15% of 1 kg = 150 g | 5 g in 1 kg = 0.5% |
| 20% of 1 kg = 200 g | 10 g in 1 kg = 1% |
| 25% of 1 kg = 250 g | 25 g in 1 kg = 2.5% |
| 33.3% of 1 kg = 333 g | 50 g in 1 kg = 5% |
| 50% of 1 kg = 500 g | 100 g in 1 kg = 10% |
| 75% of 1 kg = 750 g | 250 g in 1 kg = 25% |
| Formula: grams = total x % / 100. Assumes total mixture = 1 kg. | |
| Substance | Solute | Assumed w/w% | g per 1 kg mixture |
|---|---|---|---|
| Salt mixture A | Dissolved salts | 3.5% | 35 g |
| Salt mixture B | NaCl | 0.9% | 9 g |
| Carbohydrate mixture | Carbohydrates | 6-8% | 60-80 g |
| Acetic acid mixture | Acetic acid | 4-5% | 40-50 g |
| Sodium hypochlorite mixture | Sodium hypochlorite (NaOCl) | 3-8% | 30-80 g |
| Hydrogen peroxide mixture | H2O2 | 3% | 30 g |
| Fat-containing mixture | Fat | 3.25-3.5% | 32.5-35 g |
| Protein mixture | Total protein | 6-8% | 60-80 g |
| Retinol-containing mixture | Retinol | 0.025-1% | 0.25-10 g |
| Salt mixture C | NaCl | 0.9% | 9 g |
| Assumed mass fractions for arithmetic examples, not verified commercial or clinical formulations. Each result is per 1 kg of total mixture. A real product’s percentage may use a different basis. | |||
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Percent to Grams Formula
The formula below calculates the mass in grams of a substance given its mass percent and total mixture mass.
- G = grams of the substance
- TM = total mass of the mixture (grams)
- POM = percent of mass the substance represents (%)
w/w% vs w/v%: A Key Distinction
Mass percent (w/w%) is 100 times the substance mass divided by total mixture mass, consistent with the IUPAC mass fraction definition. A component’s mass percentage is between 0 and 100; the component cannot exceed the whole. Mass per volume (w/v%) instead gives grams per 100 mL of final solution. These are different concentration bases. This calculator uses mass percent only.
Converting between w/w and w/v requires the solution’s density. With density ρ in g/mL, the numerical w/v percentage = w/w percentage × ρ, and w/w percentage = w/v percentage / ρ. Volume percent (v/v) is another basis and must not be inferred from pure-component density alone. For example, the official 0.9% sodium chloride injection label specifies 0.9 g per 100 mL, not per 100 g. Do not treat a volume label as a mass percentage without the required basis and density.
Worked Example
Suppose a mixture is explicitly 5.25% sodium hypochlorite (NaOCl) by mass (w/w). The total mixture weighs 750 g. How many grams of NaOCl does it contain? This is an arithmetic example, not an assumption about a product label’s concentration basis.
G = 750 g × 5.25 / 100 = 39.375 g NaOCl. At 2 maximum decimal places, the calculator displays 39.38 g; at 4 places, it displays 39.375 g.
Conversely, 9 g of NaCl in a hypothetical 1,000 g total mixture is POM = (9 / 1000) × 100 = 0.9% by mass. That arithmetic example is not the volume-based definition of a saline product. To find the total instead, 39.375 g at 5.25% by mass gives TM = 39.375 × 100 / 5.25 = 750 g. A zero percentage cannot determine a total; a positive total with zero substance gives 0%.
