mL to mg Conversion

How to use this calculator

Enter the volume in millilitres (mL). Select the substance from the dropdown. Press Calculate to see milligrams, grams, micrograms, and ounces.

mL to mg: the conversion formula

Millilitres (mL) measure volume. Milligrams (mg) measure mass. The conversion formula is:

For water: mg = mL x 1.000 x 1000 = mL x 1000. So 1 mL of water = 1000 mg. For honey: 1 mL x 1.360 x 1000 = 1360 mg.

Substance	Density (g/mL)	1 mL = ? mg	5 mL = ? mg
Water	1.000	1000 mg	5000 mg
Whole Milk	1.030	1030 mg	5150 mg
Honey	1.360	1360 mg	6800 mg
Maple Syrup	1.320	1320 mg	6600 mg
Vegetable Oil	0.917	917 mg	4585 mg
Olive Oil	0.914	914 mg	4570 mg
Ethanol	0.789	789 mg	3945 mg
Glycerin	1.260	1260 mg	6300 mg
Simple Syrup	1.200	1200 mg	6000 mg

mL to mg conversion table for water

The most common reference: converting standard kitchen and medical volumes to milligrams for water-based substances:

Volume	mL	Milligrams (mg)	Grams (g)
1 drop (medical)	0.05 mL	50 mg	0.05 g
Half teaspoon	2.5 mL	2,500 mg	2.5 g
1 teaspoon	4.929 mL	4,929 mg	4.929 g
1 tablespoon	14.787 mL	14,787 mg	14.787 g
1 fl oz	29.574 mL	29,574 mg	29.574 g
Quarter cup	59.147 mL	59,147 mg	59.147 g
Half cup	118.294 mL	118,294 mg	118.294 g
1 cup	236.588 mL	236,588 mg	236.588 g
1 litre	1000 mL	1,000,000 mg	1000 g

mL to mg in medicine and pharmacy

In medical practice, liquid doses are measured in mL but the active ingredient is stated in mg. This creates a need for conversion in two directions.

Drug concentration: The key is the stated concentration on the bottle or prescription. If a suspension says “125 mg per 5 mL,” that means every 5 mL contains 125 mg. To find how many mg in 10 mL: 10 x (125/5) = 250 mg.

Why not use mL to mg directly? Because the drug is dissolved in a solution. The total mass of 5 mL of that suspension is 5 x density (roughly 5000 mg for water-based solutions), but only 125 mg of that is the active ingredient. The rest is water, excipients, and stabilisers.

Medical volume standards:

• 0.05 mL = 1 drop (medical standard)
• 0.5 mL = common infant dose volume
• 2.5 mL = half teaspoon
• 5 mL = 1 teaspoon = standard unit for liquid medicines
• 15 mL = 1 tablespoon
• 30 mL = 1 fl oz

When a label says a dose is “200 mg / 5 mL” and you need to give 400 mg, you need 10 mL. Use the calculator if working with different concentrations.

mL to mg for cooking ingredients

Most kitchen measurements do not require milligram precision, but nutritional tracking, recipe scaling, and pharmaceutical cooking (such as making infused products) may require it.

Fats and oils: Oils weigh about 900 to 930 mg per mL. A tablespoon of olive oil (14.787 mL) = 13,510 mg = 13.51 g. Nutrition labels typically round to 14 g (because they measure before any residue sticks to the spoon).

Sweeteners: Honey (1.360 g/mL) is the densest common liquid sweetener. One tablespoon of honey = 14.787 x 1360 = 20,110 mg = 20.11 g. Food labels usually state 21 g. Maple syrup (1.320 g/mL): 1 tablespoon = 19,519 mg = 19.52 g, often listed as 20 g.

Alcohol content calculation: The density of ethanol is 0.789 g/mL. A standard 355 mL (12 fl oz) beer at 5% ABV contains 355 x 0.05 = 17.75 mL of ethanol. In milligrams: 17.75 x 789 = 14,005 mg = 14.0 g of pure alcohol. This matches the US standard drink definition of 14 g of ethanol.

mL to mg for glycerin and specialty ingredients

Glycerin (glycerol) has a density of 1.260 g/mL, making it significantly heavier than water. It is used in baking to retain moisture and in confectionery for smooth textures.

• 1 mL of glycerin = 1260 mg
• 1 teaspoon (4.929 mL) of glycerin = 6,211 mg = 6.21 g
• 1 tablespoon of glycerin = 18,632 mg = 18.63 g

Simple syrup (equal parts sugar and water) has a density of approximately 1.200 g/mL:

• 1 tablespoon of simple syrup = 17,744 mg = 17.74 g
• 1 cup of simple syrup = 284,000 mg = 284 g

Coconut milk (canned, full fat) has a density around 1.10 g/mL:

• 1 tablespoon of coconut milk = 16,266 mg = 16.27 g
• 400 mL can = 440,000 mg = 440 g

mL, mg, mcg: understanding the scale

The metric mass scale:

• 1 gram (g) = 1000 milligrams (mg)
• 1 milligram (mg) = 1000 micrograms (mcg or ug)
• 1 gram = 1,000,000 micrograms

And the volume-to-mass conversion for water:

• 1 mL of water = 1 g = 1000 mg = 1,000,000 mcg

Micrograms appear in vitamins and micronutrient contexts. Vitamin D, vitamin B12, and folate are often dosed in micrograms. The calculator shows micrograms to help with nutrient tracking from liquid sources.

Density reference for common substances

Here are the densities used in this calculator and where they come from:

Substance	Density (g/mL)	Source / Notes
Water (pure, 20 C)	0.998	NIST standard; rounded to 1.000 in practice
Whole milk	1.030	Average for 3.25% fat content
Heavy cream	1.040	36% butterfat content
Honey	1.360	Average; varies 1.33 to 1.45 with moisture
Maple syrup (Grade A)	1.320	66% Brix standard
Vegetable oil	0.917	Soybean oil average
Olive oil (extra virgin)	0.914	IOC standard range
Ethanol	0.789	NIST standard at 20 C
Glycerin	1.260	USP grade standard
Simple syrup (1:1)	1.200	50% sucrose by weight
Isopropyl alcohol	0.791	Standard at 20 C