Grams to Ounces Converter

Convert Grams to Ounces — and Ounces Back to Grams

Grams to Ounces Formula

Formula

\[ \text{oz} = \frac{m_{\text{g}}}{28.349523125} \quad (\text{avoirdupois}) \qquad \text{oz t} = \frac{m_{\text{g}}}{31.1034768} \quad (\text{troy}) \\ \text{g} = \text{oz} \times 28.349523125 \quad (\text{avoirdupois}) \qquad \text{g} = \text{oz t} \times 31.1034768 \quad (\text{troy}) \\ ]

Where:

\(m_{\text{g}}\) — mass of the object in grams (g)
\(\text{oz}\) — weight in avoirdupois ounces, the everyday ounce used for food, parcels and body weight
\(\text{oz t}\) — weight in troy ounces, used for gold, silver and other precious metals

The conversion is a simple division or multiplication because both ounce types have exact definitions in grams. One avoirdupois ounce equals 28.349523125 g (the international pound of 0.45359237 kg divided by 16), while one troy ounce equals 31.1034768 g — about 9.7% heavier.

Grams to Ounces – Calculation Example

Example: a food package is labeled 100 g and you want to know its weight in ounces for a US recipe.

\[ \text{oz} = \frac{100}{28.349523125} = 3.52739... \approx 3.5274 \ \text{oz} \\ ]

Result: 100 g ≈ 3.5274 avoirdupois ounces (about 3.53 oz, or roughly 3 oz plus half of another ounce).

If the same 100 g were silver bullion, you would use the troy ounce instead:

\[ \text{oz t} = \frac{100}{31.1034768} = 3.2151 \ \text{oz t} \\ ]

Result: 100 g ≈ 3.2151 troy ounces — noticeably fewer, because a troy ounce is heavier.

How to Use the Calculator

Choose the Ounce type: Avoirdupois ounces for food, postal and general weights, or Troy ounces for gold, silver and precious metals.
Type your value into Grams (g) to convert grams to ounces, or into Ounces (oz) to convert ounces back to grams — the converter follows whichever field you edited last.
Read the results: the converted value, a pounds-plus-ounces breakdown, the formula filled in with your numbers, and two conversion tables (1–1000 g in ounces and 1–32 oz in grams).
If you switch the ounce type, the value you entered is preserved and recalculated with the new ounce definition.

What Is an Ounce, and Which One Do You Need?

The ounce is a unit of weight from the imperial and US customary systems, still used widely in the United States, the United Kingdom and in international trade. Recipes, nutrition labels, postage rates and gym dumbbells in these countries are commonly expressed in ounces (oz), while most of the world works in grams. Converting between the two is one of the most frequent everyday unit conversions — a recipe calling for "4 oz of cheese" means about 113 g.

There are in fact two different ounces, and picking the wrong one is the most common mistake. The avoirdupois ounce (28.35 g) is the default for everything ordinary: food, letters, baby weights, cosmetics. The troy ounce (31.10 g) is used almost exclusively for precious metals. When you see a gold or silver price quoted "per ounce," it is always the troy ounce — that is why a "1 oz" gold coin weighs more than a "1 oz" candy bar. Multiplying grams by the wrong factor introduces an error of nearly 10%.

The result also includes a pounds-plus-ounces breakdown because the ounce is not the largest imperial weight unit: 16 avoirdupois ounces make 1 pound (lb). A weight of 40 oz is therefore more naturally written as 2 lb 8 oz. For troy weights, the relationships are different: 12 troy ounces make 1 troy pound.

For quick mental math, remember that 1 g ≈ 0.035 oz (so 100 g ≈ 3.5 oz) and 1 oz ≈ 28.35 g (so 1 kg ≈ 35.27 oz). If you work with larger masses, our kg to lbs converter handles kilograms and pounds directly.

Assumptions, Limitations and Practical Tips

All values are non-negative weights; this converter does not handle negative numbers or temperatures.
The math uses the exact legal definitions (1 avoirdupois oz = 28.349523125 g, 1 troy oz = 31.1034768 g), then rounds for display, so results are accurate to the precision shown rather than to approximate rules like "1 oz ≈ 28 g."
Beware of fluid ounces (fl oz): they measure volume, not weight. A fluid ounce of water weighs about 29.6 g, but a fluid ounce of honey weighs about 42 g — density matters, so you cannot convert between them without knowing what liquid you have.
When buying gold or silver, check the listing carefully: bullion is quoted in troy ounces, but some jewelry listings use grams or pennyweights. The our gold karat purity converter can help you interpret fineness markings once you know the weight.
Nutrition labels in the US show both ounces and grams per serving; this converter lets you check either direction instantly.
For very small medicinal or laboratory doses, a unit converter alone is not enough — always confirm dosing with a professional or an appropriate device.

Frequently Asked Questions

How do I convert grams to ounces by hand without a calculator?

Divide the number of grams by 28.35. A useful shortcut: 100 g ≈ 3.5 oz, so 250 g is about 2.5 × 3.5 = 8.8 oz. For a rough estimate in your head you can also divide grams by 30 and accept a small error. Since 1 g ≈ 0.035 oz, multiplying grams by 0.035 works just as well for everyday cooking and shopping needs.

Is a fluid ounce (fl oz) the same as a regular ounce?

No — this is the most common source of confusion. A fluid ounce measures volume, while a regular (avoirdupois) ounce measures weight. They only coincide roughly for water: 1 US fl oz of water weighs about 29.6 g, only slightly more than 1 oz (28.35 g). For denser liquids like honey or syrup, the same volume weighs far more, so never substitute one unit for the other in recipes without checking density.

Why does my gold weigh fewer ounces than my food scale says?

Because precious metals use the troy ounce (31.10 g), which is about 9.7% heavier than the everyday avoirdupois ounce (28.35 g). A kitchen scale showing "1 oz" of gold is displaying avoirdupois ounces, but bullion buyers and spot prices quote troy ounces. If you divide your gold's grams by 31.1034768 instead of 28.35, you will get the correct bullion weight — and a fair price.

How many ounces are in a pound, and how do I read the pounds-plus-ounces result?

There are 16 avoirdupois ounces in one pound, so a weight like 50 oz equals 3 lb 2 oz. The calculator performs this division automatically. Note that troy weights use a different rule: only 12 troy ounces make 1 troy pound, and the troy pound is rarely used today. If you see a body weight like "8 st 4 lb" in the UK, remember 1 stone is 14 lb.

How do I convert kilograms to ounces in one step?

Multiply kilograms by 35.274, because 1 kg = 1000 g and 1000 ÷ 28.349523125 ≈ 35.274 oz. So a 5 kg dumbbell is about 176 oz, which is 11 lb 0 oz. Going the other way, divide ounces by 35.274 to get kilograms. This one factor is handy for shipping weights, gym equipment, and luggage limits quoted in kg but checked against US airline allowances in pounds.

What is a pennyweight, and how does it compare to grams and ounces?

A pennyweight (dwt) is an old troy unit still used by some jewelers and pawn shops: 1 dwt = 1.555 g, and 20 dwt = 1 troy ounce. If a listing quotes your gold in pennyweights, divide by 20 to get troy ounces or multiply by 1.555 to get grams, then verify with this converter. Always confirm which unit a dealer is using before agreeing to a price, since mixing up dwt and grams shifts the value significantly.

I got different results on another converter — which one is right?

Most likely the other tool used a rounded factor, such as 1 oz = 28 g or 28.3 g, while this converter applies the exact legal definition of 28.349523125 g per ounce. Differences in the third or fourth decimal are harmless for cooking, but they matter for precious metals and bulk goods. Also check whether the other site silently used troy ounces — that would explain a result roughly 10% lower than expected.