Cooking and Baking Conversions: Cups, Grams, Milliliters, and Oven Temperatures

If you have ever followed a recipe from another country and ended up with a flat cake or a soupy batter, you have run into the messy world of cooking conversions. A cup in the United States is not the same as a cup in Australia, a tablespoon of flour weighs nothing like a tablespoon of honey, and oven dials use at least three different scales depending on where you live. None of this is hard once you understand the one idea behind it: volume and weight are not interchangeable, and the bridge between them is the density of each ingredient.

This guide walks through the exact figures you need for cups, grams, milliliters, and oven temperatures, with worked examples and the mistakes that trip people up most often. For anything where precision really matters, such as scaling a recipe for a professional kitchen, confirm critical values against the ingredient packaging or a trusted reference before you commit.

Why volume and weight are not the same thing

A milliliter measures volume, the amount of space something takes up. A gram measures mass, how much matter is there. They only line up neatly for water, where 1 milliliter weighs almost exactly 1 gram at room temperature. For everything else, the relationship depends on density, which is just how tightly packed the ingredient is. A cup of feathers and a cup of lead share a volume but not a weight, and the same logic applies to flour versus sugar versus butter.

This is why two cooks measuring one cup of flour can end up with very different amounts. Scooping the cup directly into the bag compresses the flour and can add 20 to 30 percent more than spooning it in lightly and leveling the top. That single difference is enough to turn a tender cake dense. It is the core reason serious bakers reach for a scale.

The exact volume conversions

Volume-to-volume conversions are fixed numbers, so you can rely on them exactly. The values below are for the US customary system, which is what most American recipes use:

• 1 US cup = 236.588 milliliters
• 1 US tablespoon = 14.7868 milliliters
• 1 US teaspoon = 4.92892 milliliters
• 1 US cup = 16 tablespoons = 48 teaspoons
• 1 US fluid ounce = 2 tablespoons = 29.5735 milliliters

In practice, most people round a US cup to 237 ml or even 240 ml, a tablespoon to 15 ml, and a teaspoon to 5 ml. Those rounded figures are fine for everyday cooking, but notice that the rounding already nudges a cup from 236.6 ml up toward 240 ml, which hints at the international confusion we will cover shortly.

Converting cups to grams by ingredient

Because density varies, there is no single cups-to-grams number. You need a figure for each ingredient. These are widely used approximations for one US cup, and they are good enough for home baking, though brands and how you pack the cup will shift them slightly:

• Water: about 237 grams (the easy case, since 1 ml is roughly 1 gram)
• All-purpose flour: about 120 to 125 grams when spooned and leveled
• Granulated white sugar: about 200 grams
• Butter: about 227 grams (which is why a standard US stick, half a cup, is labeled 113 grams)
• Brown sugar, packed: about 220 grams
• Honey: about 340 grams, because it is dense and heavy

Notice how far apart these are. A cup of flour and a cup of honey differ by more than 200 grams even though they occupy the same space. This is exactly why copying a recipe's cup measurements without thinking about the ingredient leads to errors, and why a number printed in grams removes all the guesswork.

Oven temperatures: Fahrenheit, Celsius, and gas marks

Oven conversions use the standard temperature formula: Celsius equals Fahrenheit minus 32, multiplied by 5, then divided by 9. The results rarely land on tidy numbers, so cooks round to the nearest sensible oven setting. Here are the conversions you will meet most often:

1. 325 degrees F = 162.8 degrees C, rounded to 160 or 165 C (gas mark 3)
2. 350 degrees F = 176.7 degrees C, rounded to 175 or 180 C (gas mark 4), the classic baking temperature
3. 375 degrees F = 190.6 degrees C, rounded to 190 C (gas mark 5)
4. 400 degrees F = 204.4 degrees C, rounded to 200 or 205 C (gas mark 6)
5. 425 degrees F = 218.3 degrees C, rounded to 220 C (gas mark 7)

Gas mark 4 corresponds to roughly 180 C, and each gas mark step is about 14 C, which is the same as 25 degrees F. One more wrinkle: if your oven is a fan or convection model, common guidance is to drop the temperature by about 15 to 20 C (roughly 25 to 35 degrees F) from the conventional setting, because moving air cooks faster.

US cup, metric cup, or UK cup?

Here is the trap that ruins many imported recipes. The word cup does not mean one fixed amount around the world:

• US customary cup: 236.588 ml, used in standard American recipes
• US legal cup: 240 ml, used on nutrition labels in the United States
• Metric cup: 250 ml, used in Australia and New Zealand (Canadian recipes are mixed, often using either 250 ml or the US cup)
• UK: modern British recipes usually weigh in grams and milliliters rather than using a cup at all

The gap between a 236.6 ml US cup and a 250 ml metric cup is about 6 percent. For a single cup that may not matter, but a recipe calling for four cups of flour could be off by more than a fifth of a cup if you use the wrong standard. Always check which country a recipe comes from before trusting its cups.

Common mistakes and practical tips

Most conversion disasters come from a handful of repeat offenders. Watch for these:

• Treating cups and grams as if there were one universal ratio. There is not; it depends entirely on the ingredient.
• Confusing a tablespoon with a teaspoon. A tablespoon is three times larger, so swapping them triples or thirds a quantity, which is a disaster with salt, baking soda, or spices.
• Forgetting to adjust for a fan oven, which can overcook the outside while the center lags.
• Packing flour into the cup. Spoon it in and level it off, or better, weigh it.
• Assuming all cups are equal. A 250 ml metric cup holds noticeably more than a 236.6 ml US cup.

The single best upgrade for accuracy is a digital kitchen scale. Baking is closer to chemistry than cooking, and weighing in grams sidesteps the entire problem of how packed your cup is, which cup standard a recipe used, and how dense each ingredient happens to be. Measure liquids by volume in milliliters if you like, but weigh your flour, sugar, and butter. Your cakes will thank you, and your results will finally be repeatable batch after batch.