Ounces to Grams

Baking an American Recipe on a Metric Scale

American baking recipes are written in ounces and cups; kitchen scales sold almost everywhere else start up in grams. So a formula that calls for 4 1/4 oz of flour and a stick of butter has to be translated before the mixer is switched on — and unlike a rough substitution in a stew, a bread or cake formula punishes a sloppy translation.

Conversion factor: 1 oz = 28.349523125 g exactly, so multiply the ounce figure by 28.349523125. One stick of butter at 4 oz is 113.4 g, and a full 16 oz pound of flour is 453.59 g.

Three Ways a Recipe Can State the Same Amount

Ounces by weight

The form serious American bakers prefer: 4 1/4 oz flour, 7 oz sugar, 3 1/8 oz oats. Unambiguous, and the easiest kind of recipe to move onto a metric scale.

Cups by volume

The same ingredient measured by the space it fills. Convenient at the counter, but the weight inside one cup depends on how the ingredient was scooped and settled.

Sticks and packets

American butter is sold in 4 oz sticks marked with tablespoon lines, so recipes say “1 stick” where a metric recipe would simply say 113 g.

What the scale wants

Household kitchen scales read to 1 g, occasionally 0.1 g. That resolution is finer than any cup measure, which is why the metric figure is the one worth writing down.

Rewriting an Ingredient List Before You Start

Do the whole list once, on paper or in a note, then bake from your own metric version rather than converting halfway through with sticky hands.

Enter each ounce amount

Type the figure from the recipe into the left field — 4.25 for 4 1/4 oz, 7.5 for 7 1/2 oz. Fractions have to be typed as decimals, and a comma is accepted in place of the decimal point.

Round to what your scale can show

4.25 oz comes out at 120.49 g; write 120 g. A scale that steps in whole grams cannot act on the decimals anyway, and for flour that difference is far smaller than the variation between two scoops.

Copy the number into your own recipe note

The copy button puts the bare figure on the clipboard, with no unit and no thousands spacing, so it drops straight into a notes app or spreadsheet. Ctrl + C in a field does the same.

Go the other way for a metric recipe

The swap button (↔) turns the page into g → oz, which is what you need when a European recipe has to be read against an American ingredient chart. Divide by 28.349523125 by hand: 200 g is 7.0548 oz.

Check the abbreviation first: “oz” is a weight and “fl oz” is a volume. They are not interchangeable, and treating one as the other is the single most common way a converted recipe goes wrong.

What One US Cup of Each Baking Staple Weighs

Published ingredient charts list a cup in both ounces and grams. The middle column is the exact arithmetic; the last column is the figure the charts actually print, rounded to something a kitchen scale can hit.

Ingredient (1 US cup)	Recipe weight	Exact conversion	Chart figure
All-purpose flour	4 1/4 oz	120.49 g	120 g
Granulated sugar	7 oz	198.45 g	198 g
Brown sugar, packed	7 1/2 oz	212.62 g	213 g
Confectioners' sugar	4 oz	113.40 g	113 g
Butter (2 sticks)	8 oz	226.80 g	227 g
Unsweetened cocoa	3 oz	85.05 g	84 g
Old-fashioned rolled oats	3 1/8 oz	88.59 g	89 g

The cocoa row shows why it pays to keep one chart rather than mix several: the exact conversion of 3 oz is 85.05 g, but the commonly published cup figure is 84 g. A gram either way is invisible in a cake — the trap is combining a flour weight from one source with a sugar weight from another and losing the ratio the recipe was built on.

Handy Details in the Kitchen

Half batches without the fractions

Typing 2.125 for half of 4 1/4 oz gives 60.24 g straight away, which beats halving cup measures with a knife and a guess.

Reads a metric recipe backwards

Swapping the sides answers the opposite question — what a 250 g quantity looks like in the ounces an American chart is written in.

Drams, pounds and kilos too

The searchable dropdowns hold all eighteen weight units, so an old spice quantity in drams or a 5 lb sack of flour converts on the same page.

Both fields stay editable

Change either box and the other follows, so you can walk down an ingredient list without clearing anything between entries.

Kitchen Scale Questions

My recipe says 8 fl oz of milk — is that 227 g?

No. A fluid ounce measures volume, not weight, and 8 fl oz is one US cup — about 237 ml. Water at that volume happens to weigh roughly 237 g, and milk a little more at around 245 g, because milk is denser than water. Only for water does the two-number coincidence come close, and it never holds for oil, honey or syrup. If the recipe writes “fl oz”, reach for a jug, not the scale.

Why does my cup of flour never weigh the same twice?

Because a cup measures space and flour compresses. Dipping the cup into the bag and packing it can hold 140 g or more, while spooning flour in loosely and levelling the top gives about 120 g. That spread is over 15% on the main structural ingredient in a cake — the difference between tender and dry. Weighing sidesteps the whole problem: 4 1/4 oz is 120.49 g whichever way it reached the bowl.

How do I scale a recipe up or down once everything is in grams?

Multiply every weight by the same factor and the ratios hold — that is the real advantage of a weight-based formula. For a batch and a half, 120 g of flour becomes 180 g and 198 g of sugar becomes 297 g. Eggs are the awkward part: weigh them out of the shell, because a large egg is roughly 50 g without it, and take the fraction you need. Baking time changes with pan depth, not with the multiplier.

Does it matter if I round 4 oz down to 113 g?

For flour, sugar, butter and liquids, no — 4 oz is 113.40 g, so rounding loses 0.4 g out of 113, about a third of one per cent, well inside the tolerance of a domestic scale. Where it does matter is on the small, powerful ingredients: salt, baking powder, baking soda and instant yeast are weighed in single grams, and rounding 0.25 oz to 7 g instead of 7.09 g is fine, but rounding to the nearest 5 g is not. Use a 0.1 g scale for those.

What is the tidiest way to weigh honey or peanut butter?

Put the mixing bowl on the scale, press the zero button so the display returns to 0 g, and spoon the sticky ingredient straight in until you reach the target. Nothing is left behind in a measuring cup, and there is one less thing to wash. Zero the scale again after each addition and you can build the whole dry mix in one bowl — 120 g flour, zero, 198 g sugar, zero, and so on — reading each ingredient on its own rather than doing running totals in your head.