How many milligrams are in 1 gram?

There are 1,000 milligrams (mg) in 1 gram (g).

How do you convert grams to milligrams quickly?

Multiply the number of grams by 1,000 to get milligrams.

How do you convert milligrams to grams?

Divide the number of milligrams by 1,000 to get grams.

Why is 1 g equal to 1000 mg?

Because 'milli' means 1/1000, so 1 gram = 1000 milligrams by definition of the metric system.

What's the difference between g and mg in medication dosing?

Grams (g) are used for larger doses; milligrams (mg) for smaller, more precise doses.

Can I use this for nutrition labels and supplements?

Yes, this converter works for all medication and supplement measurements using the metric system.

What if my value is very large (e.g., 10,000 mg)?

The calculator handles any size; 10,000 mg = 10 g easily.

Does rounding affect clinical safety?

Yes, for potent medications rounding can matter; always round to the smallest syringe marking.

What's a common g vs mg conversion mistake?

Forgetting that mg is smaller, leading to 1000× dosing errors.

How do I double-check the result manually?

Use the reverse formula: if 500 mg ÷ 1,000 = 0.5 g, then 0.5 g × 1,000 should = 500 mg.

Grams to Milligrams (g to mg) Converter

Convert between grams and milligrams using SI prefix definitions. Both directions supported with adjustable decimal precision.

Value

Direction

How SI Prefixes Work

Milli is the SI prefix for 10⁻³, meaning 1 milligram is one-thousandth of a gram. To convert between grams and milligrams, you multiply when going from grams to milligrams (g → mg) and divide when going from milligrams to grams (mg → g).

Formulas

g → mg: mg = g × 1,000

mg → g: g = mg ÷ 1,000

Worked Examples

Example 1: Convert 0.5 g to mg

mg = 0.5 × 1,000

mg = 500

Answer: 500 mg

Example 2: Convert 250 mg to g

g = 250 ÷ 1,000

g = 0.25

Answer: 0.25 g

Example 3: Convert 2.75 g to mg

mg = 2.75 × 1,000

mg = 2,750

Answer: 2,750 mg

When This Converter Is Used

•Converting medication or supplement doses between grams and milligrams
•Reading nutrition labels and product dosing information
•Comparing medication strengths across different formulations

Clinical safety note: Always verify conversions and follow your facility's protocols. This calculator supports verification but does not replace clinical judgement.

Related Calculators

mcg ↔ mg

Micrograms to Milligrams

L ↔ mL

Liters to Milliliters

kg ↔ lbs

Kilograms to Pounds

°C ↔ °F

Celsius to Fahrenheit

Frequently Asked Questions

Clinical reminder: Always follow local protocols and consult medication information sheets. These examples are for calculation practice only.

References & Sources

These sources define SI prefixes and unit conventions used for g ↔ mg conversion.

International

BIPM — SI Prefixes (PDF) p.1

Single-page SI prefix chart defining milli (10⁻³).

↗

United States

NIST — Metric (SI) Prefixes

Official US standards for SI prefix naming and values.

↗

NIST — The International System of Units (SI) (SP 330 PDF)

Comprehensive SI unit definitions.

↗

United Kingdom

NPL (UK) — The SI units

UK standards for SI prefix table.

↗

NPL (UK) — SI Prefixes (PDF)

Official SI prefix reference.

↗

Australia

Australian Government Style Manual — Measurement and units (SI prefixes)

Official Australian measurement standards.

↗

Australian legal units — National Measurement Regulations 1999 (Schedule: SI prefixes)

Legal SI prefix definitions in Australia.

↗

National Measurement Institute — Australia's measurement system

Overview of Australian measurement standards.

↗

Grams to Milligrams (g to mg) Converter

Convert between grams and milligrams using SI prefix definitions. Both directions supported with adjustable decimal precision.

Value

Direction

How SI Prefixes Work

Formulas

g → mg: mg = g × 1,000

mg → g: g = mg ÷ 1,000

Worked Examples

Example 1: Convert 0.5 g to mg

mg = 0.5 × 1,000

mg = 500

Answer: 500 mg

Example 2: Convert 250 mg to g

g = 250 ÷ 1,000

g = 0.25

Answer: 0.25 g

Example 3: Convert 2.75 g to mg

mg = 2.75 × 1,000

mg = 2,750

Answer: 2,750 mg

When This Converter Is Used

•Converting medication or supplement doses between grams and milligrams
•Reading nutrition labels and product dosing information
•Comparing medication strengths across different formulations

Clinical safety note: Always verify conversions and follow your facility's protocols. This calculator supports verification but does not replace clinical judgement.

Related Calculators

mcg ↔ mg

Micrograms to Milligrams

L ↔ mL

Liters to Milliliters

kg ↔ lbs

Kilograms to Pounds

°C ↔ °F

Celsius to Fahrenheit

Frequently Asked Questions

Clinical reminder: Always follow local protocols and consult medication information sheets. These examples are for calculation practice only.

References & Sources

These sources define SI prefixes and unit conventions used for g ↔ mg conversion.

International

BIPM — SI Prefixes (PDF) p.1

Single-page SI prefix chart defining milli (10⁻³).

↗

United States

NIST — Metric (SI) Prefixes

Official US standards for SI prefix naming and values.

↗

NIST — The International System of Units (SI) (SP 330 PDF)

Comprehensive SI unit definitions.

↗

United Kingdom

NPL (UK) — The SI units

UK standards for SI prefix table.

↗

NPL (UK) — SI Prefixes (PDF)

Official SI prefix reference.

↗

Australia

Australian Government Style Manual — Measurement and units (SI prefixes)

Official Australian measurement standards.

↗

Australian legal units — National Measurement Regulations 1999 (Schedule: SI prefixes)

Legal SI prefix definitions in Australia.

↗

National Measurement Institute — Australia's measurement system

Overview of Australian measurement standards.

↗

Grams to Milligrams (g to mg) Converter

How SI Prefixes Work

Formulas

Worked Examples

When This Converter Is Used

Related Calculators

Frequently Asked Questions

QHow many milligrams are in 1 gram?

QHow do you convert grams to milligrams quickly?

QHow do you convert milligrams to grams?

QWhy is 1 g equal to 1000 mg?

QWhat's the difference between g and mg in medication dosing?

QCan I use this for nutrition labels and supplements?

QWhat if my value is very large (e.g., 10,000 mg)?

QDoes rounding affect clinical safety?

QWhat's a common g vs mg conversion mistake?

QHow do I double-check the result manually?

References & Sources

International

United States

United Kingdom

Australia

Grams to Milligrams (g to mg) Converter

How SI Prefixes Work

Formulas

Worked Examples

When This Converter Is Used

Related Calculators

Frequently Asked Questions

QHow many milligrams are in 1 gram?

QHow do you convert grams to milligrams quickly?

QHow do you convert milligrams to grams?

QWhy is 1 g equal to 1000 mg?

QWhat's the difference between g and mg in medication dosing?

QCan I use this for nutrition labels and supplements?

QWhat if my value is very large (e.g., 10,000 mg)?

QDoes rounding affect clinical safety?

QWhat's a common g vs mg conversion mistake?

QHow do I double-check the result manually?

References & Sources

International

United States

United Kingdom

Australia