Weight Converter
Conversion Formula
Grams to Kilograms Formula
To convert between grams and kilograms, use these formulas:
Kilograms to Grams Formula
Enter a value in either field above to see the conversion result in the other field.
Common Conversions
| Grams | Kilograms |
|---|---|
| 1 g | 0.001 kg |
| 10 g | 0.01 kg |
| 100 g | 0.1 kg |
| 500 g | 0.5 kg |
| 1000 g | 1 kg |
| 5000 g | 5 kg |
About Weight Units
The gram (g) is a metric unit of weight defined as one thousandth of a kilogram. It's widely used for measuring small masses in cooking, laboratory work, and everyday measurements.
The kilogram (kg) is the base unit of mass in the International System of Units (SI). It's defined by the Planck constant, which is exactly 6.62607015×10−34 joule-seconds. One kilogram equals 1000 grams.
Practical Applications
Converting between grams and kilograms is essential for:
- Cooking and recipe scaling
- Scientific measurements and experiments
- Pharmaceutical dosage calculations
- Nutritional information and dietary tracking
- Industrial manufacturing and material quantities
About Kilograms
Typical Use Cases
The kilogram is the fundamental unit of mass in the metric system, used globally for measuring everything from human body weight to industrial materials. It's the standard in laboratories for precise scientific measurements, in commercial settings for product packaging, and in medical contexts for dosage calculations. Most countries outside the United States use kilograms for all weight-related measurements, making it essential for international commerce and communication.
Historical Background
The kilogram was originally defined in 1795 as the mass of one liter of water at 4°C. For over a century, it was the only SI unit defined by a physical object: the International Prototype Kilogram, a platinum-iridium cylinder stored in France. In 2019, the kilogram was redefined using the Planck constant (6.62607015×10⁻³⁴ joule-seconds), making it based on fundamental physical constants rather than a physical artifact.
Conversion Tips
Converting between grams and kilograms is straightforward because of the decimal-based metric system: simply divide grams by 1000 to get kilograms, or multiply kilograms by 1000 to get grams. For quick mental math, remember that 500g = 0.5kg, 250g = 0.25kg, and 750g = 0.75kg. When working with very precise laboratory measurements, note that our converter maintains accuracy to three decimal places.
Frequently Asked Questions
How many grams are in a kilogram?
One kilogram equals exactly 1000 grams. This is the foundation of the metric system, making conversions simple and precise.
How do I convert 500 grams to kilograms for baking recipes?
To convert grams to kilograms, divide by 1000. So 500g = 0.5 kg. For baking, grams are preferred for precision—especially for flour, sugar, and butter where 10-20 gram differences affect texture. Professional bakers use grams exclusively because "1 cup flour" can vary by 30g depending on how it's measured.
How do I read nutrition labels that list serving sizes in grams vs kilograms?
Nutrition labels typically show grams per serving (e.g., "28g" for chips). To calculate daily intake in kilograms, add up all grams and divide by 1000. For example: breakfast cereal (60g) + lunch salad (250g) + dinner pasta (150g) = 460g total = 0.46 kg. Tracking macronutrients (protein, carbs) in grams is standard, but total daily food intake is easier to visualize in kilograms.
Why do scientific experiments require measurements in grams instead of kilograms?
Laboratory work prioritizes precision, and grams provide finer resolution for reagents and samples. Measuring 0.025 kg is less intuitive than 25g, and analytical balances display grams with milligram precision (e.g., 25.003g). For chemistry, using grams reduces decimal errors in calculations. Only large-scale industrial processes routinely work in kilograms.
When should I use grams vs kilograms in daily life?
Use grams for items under 1 kg: food ingredients (200g cheese), postage (85g letter), jewelry, or small packages. Use kilograms for body weight (68 kg), luggage (23 kg limit), bulk groceries (5 kg rice), or gym weights (20 kg barbell). The 1000:1 ratio makes mental conversion easy: 1500g = 1.5 kg, 0.75 kg = 750g.
How precise should my gram-to-kilogram conversions be for cooking?
For most cooking, rounding to one decimal place (0.1 kg = 100g) is sufficient. Baking requires more precision: use grams for ingredients under 500g (flour, sugar, butter), and kilograms only for bulk quantities (5 kg bag of flour). Recipe scaling errors multiply, so converting 450g flour to "0.45 kg" then back risks precision loss—keep measurements in grams throughout.
Is this converter accurate for laboratory and scientific applications?
Yes! Our tool provides precision to three decimal places, exceeding typical analytical balance accuracy (±0.001g). For lab work requiring exact conversions (e.g., preparing 0.250 kg = 250.000g of solution), our calculator ensures no rounding errors. Always verify conversions for regulated pharmaceutical or research applications against certified standards.
About Our Conversion Standards
Our weight conversions are based on the International System of Units (SI) and standards published by the National Institute of Standards and Technology (NIST). All conversion factors are accurate to at least 6 decimal places, ensuring precision for both everyday and professional use.
Data Sources: NIST Handbook 44, International Bureau of Weights and Measures (BIPM), ISO 80000-3:2006
Last Verified: October 2025