mL to kg Calculator
Convert milliliters to kilograms using substance density. Since milliliters measure volume and kilograms measure mass, you need the density of the substance to convert between them. The formula is kg = (mL x density) / 1000.
How to Convert mL to kg
- Identify the substance and find its density in g/mL.
- Multiply the volume in milliliters by the density to get grams.
- Divide the grams by 1000 to convert to kilograms.
Formula
kg = (mL x density in g/mL) / 1000
grams = mL x density
Example Calculation
Convert 750 mL of milk to kg:
Density of whole milk = 1.03 g/mL
Mass = 750 mL x 1.03 g/mL = 772.5 g
kg = 772.5 / 1000 = 0.7725 kg
Substance Density Reference Table
| Substance | Density (g/mL) | 1000 mL = kg |
|---|---|---|
| Water | 1 | 1.000 kg |
| Milk (whole) | 1.03 | 1.030 kg |
| Olive Oil | 0.92 | 0.920 kg |
| Vegetable Oil | 0.91 | 0.910 kg |
| Honey | 1.42 | 1.420 kg |
| Flour (all-purpose) | 0.593 | 0.593 kg |
| Sugar (granulated) | 0.85 | 0.850 kg |
| Ethanol | 0.789 | 0.789 kg |
| Gasoline | 0.75 | 0.750 kg |
| Mercury | 13.6 | 13.600 kg |
Frequently Asked Questions
Is 1 mL always equal to 1 gram?
Only for water at 4 degrees Celsius. Other substances have different densities. For example, 1 mL of honey weighs about 1.42 grams, while 1 mL of oil weighs about 0.92 grams.
How many mL are in 1 kg of water?
Since water has a density of approximately 1 g/mL, 1 kg of water equals 1000 mL (1 liter).
Why do I need density to convert mL to kg?
Milliliters measure volume while kilograms measure mass. Different substances have different masses per unit volume (density), so you need to know what substance you are measuring.
Where can I find the density of a substance?
Check the product label, material safety data sheet (MSDS), or a chemistry reference. Temperature affects density, so use values at room temperature for everyday calculations.
How do I convert mL to kg for cooking ingredients?
Use the density of the ingredient. For example, 250 mL of flour (density 0.593 g/mL) = 250 x 0.593 = 148.25 g = 0.148 kg.
Solved Examples
Example 1: Convert 2000 mL of water to kg
Solution:
Step 1: Identify density of water = 1.0 g/mL
Step 2: Calculate grams: 2000 mL × 1.0 = 2000 g
Step 3: Convert to kg: 2000 ÷ 1000 = 2.0 kg
Answer: 2000 mL of water = 2.0 kg
Example 2: Convert 1500 mL of olive oil to kg
Solution:
Step 1: Identify density of olive oil = 0.92 g/mL
Step 2: Calculate grams: 1500 mL × 0.92 = 1380 g
Step 3: Convert to kg: 1380 ÷ 1000 = 1.38 kg
Answer: 1500 mL of olive oil = 1.38 kg
Example 3: Convert 500 mL of honey to kg
Solution:
Step 1: Identify density of honey = 1.42 g/mL
Step 2: Calculate grams: 500 mL × 1.42 = 710 g
Step 3: Convert to kg: 710 ÷ 1000 = 0.71 kg
Answer: 500 mL of honey = 0.71 kg
Example 4: Convert 250 mL of flour to kg
Solution:
Step 1: Identify density of all-purpose flour = 0.593 g/mL
Step 2: Calculate grams: 250 mL × 0.593 = 148.25 g
Step 3: Convert to kg: 148.25 ÷ 1000 = 0.14825 kg
Answer: 250 mL of flour ≈ 0.148 kg
Practice Questions
- Convert 1000 mL of milk to kg. (Answer: 1.03 kg)
- How many kg is 3000 mL of gasoline? (Answer: 2.25 kg)
- A bottle contains 750 mL of honey. What is its mass in kg? (Answer: 1.065 kg)
- Convert 100 mL of mercury (density 13.6 g/mL) to kg. (Answer: 1.36 kg)
- How many kg does 2500 mL of vegetable oil weigh? (Answer: 2.275 kg)
- Convert 400 mL of ethanol (density 0.789 g/mL) to kg. (Answer: 0.3156 kg)
Common Mistakes to Avoid
A very common error is simply dividing mL by 1000 to get kg, which only works for water. For any other substance, you must multiply by density first. For instance, 1000 mL of olive oil is not 1 kg — it is actually 0.92 kg because oil is lighter than water. Another mistake is forgetting the two-step process: first convert mL to grams (multiply by density), then convert grams to kg (divide by 1000). Skipping either step gives the wrong answer. People also frequently confuse liters with kilograms, assuming 1 liter = 1 kg universally, but this equivalence only holds for water. For industrial and shipping calculations, this error can lead to significant weight miscalculations. Temperature changes can also affect results — a fuel tank in summer contains less mass per liter than in winter due to thermal expansion.
Key Takeaways
- The core formula is: kg = (mL × density in g/mL) ÷ 1000
- 1 mL = 1 cc = 1 cm³ — all three are the same volume unit
- For water: 1000 mL = 1 kg exactly (density = 1.0 g/mL)
- This is a two-step conversion: volume → grams (using density) → kg (divide by 1000)
- For large-volume calculations (fuel, bulk liquids), even small density differences lead to significant kg differences
- Always verify density at the relevant temperature when precision matters, especially for volatile liquids and heated substances