Cooking Weight Converter
Weight measurements in cooking use either metric (grams, kilograms) or US customary (ounces, pounds) units. Metric units are the standard in professional kitchens, scientific cooking, and most modern recipes worldwide. US customary units are common in North America and older recipes. Weight measurements are more accurate than volume measurements because they measure the actual mass of an ingredient, which does not vary with how the ingredient is scooped or packed. A cup of flour weighs the same whether it is lightly spooned or firmly packed, but the volume may differ; weight eliminates this ambiguity. Converting between grams, ounces, and pounds is essential for following recipes from different sources, adapting quantities, and ensuring consistent results in baking and cooking. Remember: weight ounces (oz, avoirdupois) measure mass and should not be confused with fluid ounces, which measure volume. This calculator displays five cooking weight units simultaneously: milligrams, grams, kilograms, ounces (avoirdupois), and pounds. Type a value into any field and all others update instantly.
Cooking weight conversion factors
All conversions below use metric and avoirdupois standards, with all units expressed relative to grams (g).
| Unit | Symbol | Grams (g) |
|---|---|---|
| Milligram | mg | 0.001 |
| Gram | g | 1 |
| Kilogram | kg | 1,000 |
| Ounce | oz | 28.349523 |
| Pound | lb | 453.59237 |
Note: These conversions use weight ounces (avoirdupois), not fluid ounces (volume). These are different units and cannot be directly compared.
Cooking weight converter: frequently asked questions
What is the difference between weight and fluid ounces?
Weight ounces (oz, avoirdupois) measure mass or weight. Fluid ounces (fl oz) measure volume. They are different units and cannot be directly converted without knowing the density of the ingredient. For water, 1 fluid ounce weighs approximately 1 ounce, but for flour, honey, or other ingredients, the relationship differs.
How do I convert ounces to grams?
One ounce (avoirdupois) equals 28.3495 grams. One pound equals 453.592 grams. For practical cooking, 1 ounce is often approximated as 28 grams or 30 grams (error depends on precision needed). This calculator uses precise conversion factors.
Why do some recipes use weight and others use volume?
Weight measurements (grams, ounces, pounds) are more accurate and consistent because they measure the actual mass of an ingredient. Volume measurements (cups, tablespoons) vary depending on how the ingredient is packed or scooped. Professional bakers prefer weight for precise results. Home cooks often use volume for convenience.
Should I use US or metric for cooking?
Metric (grams, millilitres) is more accurate and is the standard in professional kitchens and most modern recipes. US customary (ounces, pounds, cups) is common in US recipes and home cooking. Check the recipe origin. When in doubt, metric is typically more reliable for precision.
Is an ounce the same as 28 grams?
One ounce equals 28.3495 grams, so for practical cooking, 28 grams is a close approximation. However, this introduces a 0.35 gram error per ounce. For precise baking (where grams matter), use the accurate conversion. For casual cooking, 28 or 30 grams per ounce is sufficient.
Official sources
- NIST Handbook 44: Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices.
- NIST Special Publication 330: The International System of Units.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.