Ounces to Grams Converter — oz to g

The Conversion: 1 Ounce = 28.3495 Grams

One avoirdupois ounce equals 28.3495 grams exactly. This is the standard ounce used for food, body weight, and most everyday measurements in the US and UK.

• Ounces → Grams: Multiply by 28.3495 (e.g., 8 oz × 28.3495 = 226.8 g)
• Grams → Ounces: Divide by 28.3495, or multiply by 0.035274 (e.g., 100 g × 0.035274 = 3.527 oz)

Quick mental estimate: There are roughly 28 grams per ounce. So 4 oz ≈ 112 g, 8 oz ≈ 224 g, 16 oz (1 lb) = 454 g.

Note on troy ounces: Precious metals use the troy ounce = 31.1035 grams — about 10% heavier than the standard avoirdupois ounce. Gold and silver prices are always quoted in troy ounces. This converter uses the avoirdupois ounce for general purposes.

Ounces to Grams Conversion Table

Common ounce amounts converted to grams, with practical context for each:

Ounces in Cooking: US vs UK Measures

Recipes from the US and UK both use ounces, but the measurement systems differ in important ways:

• US recipes: "Ounces" for liquids usually means fluid ounces (volume). 1 US fluid ounce = 29.57 mL.
• UK recipes: Often use weight ounces for both dry and liquid ingredients. 1 UK fluid ounce = 28.41 mL.
• Weight ounce (both US and UK): Exactly 28.3495 g — this is what this converter uses.

In baking, weighing ingredients in grams is significantly more accurate than measuring by cups or tablespoons. A cup of all-purpose flour can weigh anywhere from 120 g (sifted and spooned) to 160 g (scooped and packed) — a 33% difference that dramatically affects the texture of baked goods. Professional bakers always use gram measurements for consistency.

A common source of confusion: US recipes saying "8 ounces of cream cheese" mean weight ounces (226.8 g), while "8 ounces of milk" typically means fluid ounces (236.6 mL). For water and milk (density ≈ 1 g/mL), the difference is about 4% and usually doesn't matter. For denser liquids like heavy cream or honey, the difference is more significant.

Avoirdupois vs Troy vs Apothecary Ounces

There are actually three different ounce units used in English-speaking countries, and confusing them causes errors:

The troy ounce is about 9.7% heavier than the avoirdupois ounce. A troy pound (12 troy oz) = 373.2 g, while an avoirdupois pound (16 oz) = 453.6 g. This is why the troy pound is actually lighter than the avoirdupois pound despite the troy ounce being heavier — the troy system uses 12 ounces per pound while avoirdupois uses 16.

When reading precious metal prices, always remember those are quoted in troy ounces. If gold is $2,000 per troy ounce, that's per 31.1 g, not per 28.35 g. Converting to price per gram: $2,000 ÷ 31.1035 = $64.30 per gram. This matters for jewelry valuation, investment, and customs declarations.

The apothecary ounce is historically the same as the troy ounce (31.1035 g) and was used in pharmaceutical dispensing until the 20th century. It has been largely replaced by metric units in pharmacy, but old pharmacopoeias and some homeopathic texts still reference it.

Sports Nutrition: Ounces and Grams for Athletes

Runners, cyclists, and other endurance athletes frequently convert between ounces and grams when tracking macronutrient intake, calculating race day nutrition, and reading food labels from different countries.

• Protein target example: 150g protein per day = 5.29 oz. If your chicken breast weighs 6 oz cooked, that's 170g, providing about 51g of protein.
• Carbohydrate loading: 8–10 g/kg body weight per day before a marathon. For a 70 kg runner: 560–700 g = 19.8–24.7 oz of carbohydrates.
• Gel packets: Typical energy gel = 32 g = 1.13 oz, providing ~23–25g of carbs and 100 calories.
• Race day banana: Medium banana = 118 g = 4.2 oz, providing ~27g carbs and 105 calories.
• Electrolyte tablets: Typically 5–7 g = 0.18–0.25 oz per tablet, containing 200–500 mg sodium.

Most nutrition labels in the US list serving sizes in both ounces and grams — the gram figure is more precise for tracking purposes. European food labels use grams exclusively. Sports nutrition products targeting international markets include both units. For detailed macro tracking, grams are the professional standard because they provide more decimal precision than fractional ounces.

Grams to Ounces Reference Chart

For converting from grams to ounces, this reference table covers common metric package sizes:

History of the Ounce and Gram

The avoirdupois ounce derives from medieval trade and commerce in France and England. The word "avoirdupois" comes from Old French "avoir de pois" meaning "goods of weight." The system was formalized in England in the 14th century to standardize trade in wool — one of the most valuable commodities of medieval Europe. The avoirdupois pound of 16 ounces became standard for general commerce throughout the British Empire and its successor states.

The gram was defined by the French in 1795 as part of the metric system. Originally defined as the weight of 1 cubic centimeter of water at 4°C (its maximum density), the gram is now formally defined through the kilogram, which since 2019 is defined in terms of the Planck constant — making it one of the most precisely defined measurements in history.

Today, the avoirdupois ounce is legally defined as exactly 28.349523125 grams (rounded to 28.3495 g for practical use). This exact definition links the imperial and metric systems precisely, meaning the conversion is mathematically exact — not an approximation.

Ounces and Grams in the Kitchen: A Practical Guide

The transition between ounce-based and gram-based measurement is one of the most common friction points in international cooking. American recipes use ounces and pounds; British recipes often use a mix; European, Australian, and most of the world's recipes use grams and kilograms. Understanding the conversion deeply — not just the formula but the intuitive sense of each unit — makes you a more confident cook in any kitchen.

Building gram intuition: 100 grams is the benchmark serving size on European nutrition labels — about the weight of a small apple, a standard chocolate bar, or a thick slice of bread. 250 grams is a half-pound (close to 8.8 oz) — a common butter block size in Europe. 500 grams is one European "pound" (German: Pfund) — a standard grocery package for pasta, rice, or cheese. 1 kilogram (1,000 grams) is 2.2 lbs — the European equivalent of the US 2-pound bag of flour or sugar.

Baking precision matters: A classic example of why grams beat ounces in baking: a recipe calls for 2 cups of flour. The actual weight can range from 240 grams (sifted and spooned) to 320 grams (scooped directly) — a 33% range. That difference produces dramatically different results: 240g gives a light, tender crumb; 320g gives dense, dry baked goods. Professional bakers and serious home bakers always weigh in grams for consistency, regardless of what the recipe's cup measures say.

Meat and protein conversions for meal prep: When meal prepping for a week, knowing ounce-to-gram conversions enables efficient bulk purchasing and portioning. A typical macronutrient target for a 170-lb (77 kg) athlete might be 150g protein per day. Planning 5 days of meal prep: 750g total protein content needed. At 31g protein per 100g of cooked chicken breast, that's 2,419g raw chicken to start with — about 85 oz or just over 5 pounds. The grocery list works in pounds; the food scale works in grams; you need both conversions.

Coffee and tea brewing: Specialty coffee recipes are always in grams. A standard V60 pour-over recipe: 15 grams of coffee to 250 grams (mL) of water, a 1:16.7 ratio. Espresso shots: a single is 7–9 grams of grounds producing 25–30 grams of liquid espresso. A double is 14–18 grams producing 50–60 grams. These gram-based recipes provide precision that ounce measurements — with their larger unit size — cannot easily match. 7 grams = 0.247 oz: the fractional ounce measurement is inconvenient; the gram count is clean.

Postal and shipping weights: US postal rates are calculated in ounces for lightweight items (under 16 oz = 1 lb). First-Class Mail pricing tiers: 1–3.5 oz, 3.5–7 oz, 7–13 oz. International shipments must declare weight in grams for customs forms. A small package weighing 200 grams = 7.05 oz — just over the 7-oz postal threshold. Knowing exact conversions prevents unexpected shipping cost jumps when a package is slightly over a pricing tier.

Whether you're calibrating a kitchen scale, following a recipe from a different country, calculating nutrition for meal prep, brewing precision coffee, or calculating shipping costs, the ounce-to-gram conversion of 28.3495 g/oz is one of the most used conversion factors in daily life. Memorizing this number — or at least the quick approximation of 28g per ounce — pays dividends in the kitchen and beyond. For culinary professionals, scientists, and athletes who regularly work across measurement systems, building fluency with both grams and ounces creates the ability to estimate, verify, and convert quantities intuitively without reaching for a calculator every time. The key anchor values are: 1 oz ≈ 28g, 4 oz ≈ 113g, 8 oz ≈ 227g, 16 oz = 1 lb = 454g, and 100g ≈ 3.5 oz.