It depends on the liquid's concentration (mg per mL). For water-like density (1 g/mL), 1 mL ≈ 1000 mg; medicines use their labeled mg/mL strength.

How can I convert milligrams to milliliters?

Use mL = mg ÷ (mg/mL). Enter the weight and the liquid's concentration; the calculator does it automatically.

How can I convert mL to mg?

Use mg = mL × (mg/mL). Provide the liquid's mg/mL concentration and the volume; you'll get weight instantly.

How to use this mg to mL conversion calculator?

Choose a liquid, confirm or edit the mg/mL, then type either weight or volume. The other field updates instantly. Adjust the Decimal control for output rounding.

Example of mg to mL conversion

If a syrup is 40 mg/mL and you need 100 mg, then volume = 100 ÷ 40 = 2.5 mL.

Liquid concentrations — how many milligrams in a milliliter?

Concentration expresses how much mass fits in each mL. Water ~1000 mg/mL; milk ~1030 mg/mL; cooking oil ~910 mg/mL; medicines vary widely.

mL = 5 ÷ (mg/mL). For a 40 mg/mL solution, 5 mg = 0.125 mL.

Trusted Medical Conversion Tool

mg to mL

Convert mg to mL instantly with precision. Perfect for medications, liquids, and pharmaceuticals.

mg to mL Calculator

Enter mass or volume — the other updates automatically

Precision:

Conversion Type

Concentration

mg/mL

Based on water density (1 g/mL = 1000 mg/mL)

Mass (Weight)

Volume

Concentration

1000 mg/mL

mg → mL Formula

mL = mg ÷ (mg/mL)

mL → mg Formula

mg = mL × (mg/mL)

How mg to mL Calculator Works

A simple guide to using our conversion tool

Select Your Substance

Choose the type of liquid you're converting — water, milk, medication, or enter a custom density for other substances.

Enter Milligrams

Input the number of milligrams in the Mass field. You can also switch to micrograms (µg) or grams (g) using the unit dropdown.

Get Instant Results

The volume in milliliters will be calculated automatically. You can also express it in liters, tablespoons, teaspoons, or fluid ounces.

Reverse Conversion

To convert mL to mg instead, simply enter the milliliters first — the calculator works both ways automatically.

Pro Tips

• For medications, select "Medications" and choose your specific drug
• Use precision control (+/-) for more decimal places
• Select "Custom / Other" to enter any density in mg/mL

Conversion Process Visualized

Mass (mg) 100 milligrams

↓

Formula

÷ 40 mg/mL

concentration

↓

Volume (mL) 2.5 milliliters

mL = 100 mg ÷ 40 mg/mL = 2.5 mL

mg to mL Drug conversion chart

Common medication concentrations for quick reference

Medication	Strength	Concentration	Category
Acetaminophen (Tylenol)	160 mg / 5 mL	32 mg/mL	Pain Relief
Amoxicillin Suspension	400 mg / 5 mL	80 mg/mL	Antibiotic
Ibuprofen Oral	100 mg / 5 mL	20 mg/mL	Pain Relief
Benadryl Oral	12.5 mg / 5 mL	2.5 mg/mL	Antihistamine
Cetirizine HCL	5 mg / 5 mL	1 mg/mL	Antihistamine
Azithromycin	200 mg / 5 mL	40 mg/mL	Antibiotic
Prednisolone	15 mg / 5 mL	3 mg/mL	Steroid
Omeprazole	2 mg / 1 mL	2 mg/mL	Acid Reducer
Morphine Sulfate	20 mg / 1 mL	20 mg/mL	Pain Management
Zofran (Ondansetron)	4 mg / 5 mL	0.8 mg/mL	Anti-nausea

mg to mL Conversion Chart

Quick reference for common liquid densities and conversions

Common Liquids

Liquid	Density	100 mg =
Water	1000 mg/mL	0.1 mL
Milk	1035 mg/mL	0.0966 mL
Cooking Oil	910 mg/mL	0.1099 mL
Olive Oil	920 mg/mL	0.1087 mL
Honey	1420 mg/mL	0.0704 mL
Ethanol	789 mg/mL	0.1267 mL

Water Conversion Reference

1 mg

0.001 mL

50 mg

0.05 mL

100 mg

0.1 mL

250 mg

0.25 mL

500 mg

0.5 mL

1000 mg

1 mL

mg to mL Formula

mL = mg mg/mL

Example: Convert 100 mg to mL with a 40 mg/mL concentration

mL = 100 mg ÷ 40 mg/mL = 2.5 mL

mL to mg Formula

mg = mL × (mg/mL)

Example: Convert 2.5 mL to mg with a 40 mg/mL concentration

mg = 2.5 mL × 40 mg/mL = 100 mg

mg to mL for Water

Water Density

1 g/mL = 1000 mg/mL

At standard temperature and pressure

For pure water, the conversion is straightforward because water has a density of approximately 1 gram per milliliter. This means:

✓ 1 mL of water = 1000 mg (or 1 gram)
✓ 100 mg of water = 0.1 mL
✓ 500 mg of water = 0.5 mL

Quick Water Conversions

1 mg

0.001 mL

10 mg

0.01 mL

100 mg

0.1 mL

1000 mg

1 mL

How to Convert mg to mL

Follow these simple steps for accurate conversions

Know Your Concentration

Find the mg/mL value on your medication label or use the liquid's density

Enter Your Values

Input the mass (mg) or volume (mL) you want to convert

Apply the Formula

Use mL = mg ÷ (mg/mL) or mg = mL × (mg/mL)

Get Your Result

The calculator provides instant, accurate results

How many mg in a mL?

Understanding the "m" Prefix

The letter "m" in both mg and mL stands for milli-, meaning one-thousandth (1/1000) of the base unit. So we're asking: how many thousandths of a gram are in a thousandth of a liter?

The Kilogram-Liter Relationship

In 1795, the kilogram was originally defined as equal to one liter of water at the temperature of melting ice (0°C / 32°F).

While modern definitions have been refined, this relationship remains very close — approximately 0.9998 kg per liter at standard conditions.

The Math Behind It

A milligram is a thousandth of a thousandth of a kilogram, while a milliliter is a thousandth of a liter. There's an extra "thousandth" on the weight side, so:

1,000 mg = 1 mL

(for water at standard conditions)

For Water

mL = mg ÷ 1000

Since water density is approximately 1000 mg/mL, simply divide milligrams by 1000 to get milliliters.

Example: 500 mg ÷ 1000 = 0.5 mL

For Other Liquids

mL = mg ÷ ρ

Where ρ (rho) is the density in mg/mL. Different liquids have different densities.

Milk example (ρ = 1035): 500 mg ÷ 1035 = 0.483 mL

Common Densities (mg/mL)

Water 1000

Milk 1035

Olive Oil 920

Honey 1420

Frequently Asked Questions

Everything you need to know about mg to mL conversion

How many mg in a mL?

It depends on the liquid's concentration. For pure water, 1 mL = 1000 mg because water has a density of 1 g/mL. For medications, you must use the specific mg/mL concentration listed on the product label.

How many mLs is mg?

To find how many mL a specific mg value equals, divide the mg by the concentration (mg/mL). For example, 100 mg at 20 mg/mL concentration equals 5 mL (100 ÷ 20 = 5).

Is 1 mg equal to 1 mL?

No. Milligrams (mg) measure mass/weight, while milliliters (mL) measure volume. They are only numerically equal when the concentration is exactly 1 mg/mL, which is rare for medications.

What is 100 mg converted to mL?

It depends on the concentration. For example:

• At 20 mg/mL: 100 mg = 5 mL
• At 40 mg/mL: 100 mg = 2.5 mL
• For water (1000 mg/mL): 100 mg = 0.1 mL

How do you convert mg to mL for medications?

Find the medication's concentration on the label (e.g., 100 mg/5 mL = 20 mg/mL)
Divide your dose (mg) by the concentration (mg/mL)
The result is the volume in mL

Example: If you need 80 mg and the concentration is 20 mg/mL: 80 ÷ 20 = 4 mL

What is 5 mg in mL?

It depends on the concentration:

• At 1 mg/mL: 5 mg = 5 mL
• At 5 mg/mL: 5 mg = 1 mL
• At 40 mg/mL: 5 mg = 0.125 mL

Why do I need to know the concentration?

The concentration (mg/mL) tells you how much active ingredient is dissolved in each milliliter. Without knowing the concentration, it's impossible to accurately convert between mass and volume. Different products with the same medication can have very different concentrations.

How much is 25 mL of cooking oil in mg?

Cooking oil has a density of approximately 0.91 g/mL (910 mg/mL).
25 mL × 910 mg/mL = 22,750 mg (or about 22.75 grams)

Disclaimer: This tool is for educational and informational purposes only and should not replace professional medical advice. Always consult a healthcare provider for medication dosing and follow product labeling instructions.