Ounces to Grams Conversion

How to use this calculator

Enter the number of ounces. Use decimals for fractions: 0.25 for 1/4 oz, 0.5 for 1/2 oz, 1.5 for one and a half ounces. Select the ounce type (avoirdupois for everyday use, troy for precious metals). Press Calculate to see grams, kilograms, pounds, and milligrams.

The ounce-to-gram conversion formula

The avoirdupois ounce is defined as exactly 28.349523125 grams by the international yard and pound agreement of 1959. For practical purposes, 28.35 g per ounce is accurate to within 0.002%.

Ounces to grams conversion table

Ounces (oz)	Grams (g)	Kilograms (kg)	Pounds (lb)
0.25 oz	7.09 g	0.00709 kg	0.01563 lb
0.5 oz	14.17 g	0.01417 kg	0.03125 lb
1 oz	28.35 g	0.02835 kg	0.0625 lb
2 oz	56.70 g	0.0567 kg	0.125 lb
3 oz	85.05 g	0.08505 kg	0.1875 lb
4 oz	113.40 g	0.1134 kg	0.25 lb
5 oz	141.75 g	0.14175 kg	0.3125 lb
6 oz	170.10 g	0.1701 kg	0.375 lb
7 oz	198.45 g	0.19845 kg	0.4375 lb
8 oz	226.80 g	0.2268 kg	0.5 lb
10 oz	283.50 g	0.2835 kg	0.625 lb
12 oz	340.19 g	0.34019 kg	0.75 lb
16 oz	453.59 g	0.45359 kg	1.0 lb
32 oz	907.18 g	0.90718 kg	2.0 lb

The 16 oz = 1 pound relationship is the most important to remember for kitchen use.

Avoirdupois vs troy ounce explained

Two different ounce standards exist, and mixing them up is a serious error in precious metal transactions.

Avoirdupois ounce (28.3495 g): Used for all food, body weight, postal weight, and everyday commerce. Packaged food in the US is always labelled in avoirdupois ounces. A 12 oz can of soup contains 12 avoirdupois ounces = 340.2 g.

Troy ounce (31.1035 g): Used exclusively for gold, silver, platinum, palladium, and gemstones. All precious metal spot prices quoted in “ounces” use troy ounces. A troy ounce is about 9.7% heavier than an avoirdupois ounce, which is why 1 lb of gold (weighed in troy ounces) is 12 troy oz, not 16 oz.

Why does the troy system exist? The troy weight system originated in Troyes, France, a major medieval trading centre. It was adopted for precious metals to standardise trade, and remains in use because the gold market is highly standardised internationally around this unit.

Common mistake: A recipe that calls for 4 oz of butter means 4 avoirdupois ounces = 113.4 g. Do not use the troy conversion (which would give 124.4 g) for cooking.

Common kitchen references for ounces to grams

Knowing a few anchor points helps with quick estimation:

Butter: 1 US stick = 4 oz = 113.4 g = 8 tablespoons = 1/2 cup. This is one of the most useful kitchen conversions. Recipes calling for “1/2 cup of butter” or “1 stick of butter” or “4 oz of butter” all mean the same thing.

Meat portions:

• 3 oz = 85 g (standard diet serving, roughly deck of cards)
• 4 oz = 113 g (quarter-pound burger patty before cooking)
• 6 oz = 170 g (typical restaurant chicken breast)
• 8 oz = 227 g (half-pound steak)

Chocolate: A standard US chocolate bar (Hershey’s) = 1.55 oz = 43.9 g. Baking chocolate blocks are typically 1 oz = 28.35 g each.

Cheese: A typical serving of hard cheese is 1 oz = 28.35 g (about the size of your thumb). An 8 oz block of cheese = 226.8 g.

Flour and sugar: 1 oz of all-purpose flour = 28.35 g. 1 oz of white sugar = 28.35 g. A standard 5-lb bag of flour = 80 oz = 2268 g = 2.268 kg.

Ounces to grams for international recipe conversion

UK and Australian recipes often use weight in grams or metric measurements, while US recipes use cups and ounces. Here are common recipe-quantity conversions:

US recipe amount	Grams	Metric equivalent
1 oz	28.35 g	28 g
2 oz	56.70 g	57 g
3.5 oz	99.22 g	100 g
4 oz	113.40 g	113 g
6 oz	170.10 g	170 g
7 oz	198.45 g	200 g
10 oz	283.50 g	284 g
14 oz	396.89 g	400 g
17.6 oz	499.10 g	500 g

Note that “3.5 oz” and “7 oz” are common because they approximate the clean metric quantities of 100 g and 200 g respectively.

Fluid ounces vs weight ounces

A common source of confusion in recipes: fluid ounces (fl oz) measure volume, not weight. They are not the same as avoirdupois ounces, even though they share the name “ounce.”

• 1 US fluid ounce = 29.5735 mL (volume)
• 1 avoirdupois ounce = 28.3495 g (mass)

For water, the two happen to be close in value: 1 fl oz of water weighs about 29.57 g (not 28.35 g). They are close but not equal.

For other liquids, the difference is larger. 1 fl oz of honey = 29.57 mL x 1.36 g/mL = 40.2 g — very different from 28.35 g. When a recipe says “8 oz of honey,” always check whether it means 8 fluid ounces (237 mL = 322 g) or 8 weight ounces (227 g of honey = 167 mL). This context matters for outcome.

Quick mental conversion tips

For fast kitchen estimates without a calculator:

• Multiply oz by 30 for a quick gram estimate (7% high, but easy mentally)
• Multiply oz by 28 for a closer estimate (1% low)
• Exact: multiply by 28.35

Example mental maths: 5 oz of almonds. Quick estimate: 5 x 30 = 150 g. Exact: 5 x 28.35 = 141.75 g. The “x30” estimate is reasonable for portioning but not for precision baking.

For common fractions:

• 1/4 oz = about 7 g
• 1/2 oz = about 14 g
• 3/4 oz = about 21 g
• 1 and 1/2 oz = about 43 g