how much is a cup in ml and other cooking measurement questions

How much is a cup in ml? [And other cooking measurement questions.]

So, how much is a cup in ml? This is a really common question on Google. This type of question comes a lot if you’ve ever bought the wrong edition of a recipe book. Or returned from a visit abroad with an absolute need to reproduce something you ate out there; but you can’t find the domestic recipe equivalent in your usual standard weights and measures. I’m sure there are other reasons too.

Whatever your reason for understanding cooking weights and conversions, this post is for you. In it, I will try and answer your questions about cooking measurements. I will explain why countries have evolved different weights and measures, how to cook without conversions and also provide you with FREE printable kitchen conversion charts (UK metric/imperial and US) to help you out.

So, why a post about cooking measurement conversions?

Well… I bought a recipe book using my mobile phone, phone in one hand, cooking dinner with the other… So, obviously I didn’t read the small print.  After excitedly awaiting the arrival of my new book, I opened it and soon discovered I had bought a North American copy. Yep, the weights and measures were all American weights and measures. How. Very. Annoying.

Why is it that although we share the same language we’ve developed two different measuring systems?

Anglophone countries have traditionally used two systems of cooking measurement: the US Customary System and the British Imperial System.

The English system developed first and was derived from ancient Roman, Carolingian and Saxon units of measurement. The US system was based on the English units used in the 13 original US colonies and was developed after the American Revolution.

Throughout the UK, many domestic recipes are still passed down through generations in UK imperial units. However, the UK officially adopted the metric system in 1965 and the imperial system stopped being the primary measure in 1995. Fortunately, we still sell dual measuring equipment, making modern life easier.

US & UK imperial systems are different!

Image by Thomas Northcut via Canva

Even now, in 2020 and despite Government, Industry and Commerce using the metric system, the UK still uses its imperial units for journey distances, vehicle speeds, beer glasses and other measures.  Nothing is ever simple in a country with a relatively long history!

Although the names of the UK and US measuring systems have been kept pretty much the same, surprisingly there is a difference in size. Yep, US imperial measurements are different from UK imperial measurements.

I need accuracy.

Sometimes, when trying to reproduce US recipe I’d found on the internet, I used to find myself Googling frantically trying to find that elusive page on conversions that I found so easily before. But this was pretty stressful when trying to block out all that tired, petty squabbling from other areas of the house…

To add to my plight, I’m not, what I would call a ‘natural’ cook.  I really struggle to know whether a recipe needs a ‘little more of this’ or a ‘little dash of that’ like TV chefs seem to do. (In complete contrast, my sister-in-law is utterly brilliant at this. Harumpf!)
Frankly, I need accuracy and consistency.

And I need to know that my cooking will be eaten by my children. Or at least has a chance of being so.  So, when I’ve found a winner, I NEED to be able to reproduce it every time. I don’t often have the time to test and adjust what I’m cooking before my children are demanding food and my stress level rises.  It’s also fun to be able to share those small successes with my friends and family with the confidence that my recipes will be great for them too.

This is why – for me – getting the wrong edition of a recipe book is very irritating. And, when I’ve bought it, then there’s the palaver of sending it back…

Unknown to my mother-in-law, she helped me solve my problem with alternative weights and measures.

This means I can download and purchase any recipe with impunity!   How did she do this?

My mother-in-law used to live partly in Canada and partly in the UK and so to reproduce her favorite North American recipes in the UK, she kept US measuring cups in the kitchen cupboard. She kindly donated these to me when she returned full time to Canada.

Cooking from a recipe is a bit like learning a foreign language.  It requires immersion in its specific culture of weights and measures to become fully fluent with the proportions of its ingredients. Only then, when you instinctively understand the quantities without having to translate them back to the more familiar system, does it work. Having the right measuring equipment makes this process much easier. This applies whether that system is metric, pounds and ounces, cups or anything else.

The easiest way to convert from cups to grams, or vice versa, is to keep proportions the same.

If the right measures or accurate translations of one measurement system to another are not possible, in the same way that direct translations of foreign words aren’t always possible, the easiest way to convert a recipe is to keep the proportions the same and not focus too much on the numbers. So, if your cupcake recipe demands 125g sugar, 125g flour, 125g butter, a ratio of 1:1:1, then your US recipe will be 1 c. sugar, 1 c. flour, 1 c. butter, (or vice versa).

But the scientist in me likes to use digital scales and the exact figures. If you’re like me and you can’t deal without the accuracy, the following table may be useful. I‘ve included the widely used cooking abbreviations for clarity.

UK Imperial/Metric Conversion

Ounces (Oz)Grams (g)
1 oz28 g
2 oz56 g
3 oz84 g
4 oz112 g
5 oz140 g
6 oz168 g
7 oz196 g
8 oz224 g
9 oz252 g
10 oz280 g
11 oz308 g
12 oz336 g
13 oz364 g
14 oz392 g
15 oz420 g
16 oz448 g

Although I like exact measures, most of the time, recipes don’t need exact quantities, just rough ones (or so I’m told). For example, you could substitute 25g or 30g for 1oz.  For smaller quantities, this is especially true because the errors would be really tiny. So, for little quantities of certain useful common ingredients, you can use the following approximations:

Small Quantities of Common Ingredients

Ingredient1 Level Tablespoon (1 tbsp)
Rice15 g
Sugar15 g
Butter15 g
Flour8 g
Parmesan (grated)5 g
Breadcrumbs4 g

These are only very rough measurements as the weights of different ingredients can vary a lot.  Flour, for example, will pack tighter when it’s unsifted, so 1 tbsp of unsifted flour will be heavier than 1 tbsp of sifted flour.  But it’s really useful when cooking to have a rough idea.

Now, when you’re baking

Baking is a complete science in itself that must be done utilising only one cooking language – exact measures are very important. 

I often think of baking as a chemistry experiment because that’s really what it is.  (Minus the homework at the end.) A good rule of thumb is to never mix UK metric with UK imperial or even US measurements.  You won’t be happy with the result… Trust me on this – I say it from experience!

I have to admit though, I find baking well with the US cups quite difficult. The cup system makes repetition so hard.  I can never get 1 cup of flour (or any other dry ingredient) to weigh the same twice! Baking by weight is far better for consistency.  This is really important when you’re converting from US cup measurements to UK weights as the weight will vary depending on the ingredient being measured.  For example 1 cup (US) of ground almonds maybe 100g but 1 cup of whole almonds, could be 150g. That said, the US cup measures are brilliant for measuring liquids.

The following measuring conversion chart shows US cup to fluid ounce (fl oz) to UK millilitre (ml) conversions, again with their abbreviations and to the nearest whole number:

US/UK Liquid Measure Conversions

US Cups
(c.)
US Fluid Ounces
(fl oz)
UK Fluid Ounces
(fl oz)
Millilitres
(ml)
1 c.8 fl oz9 fl oz250 ml
3/4 c.6 fl oz6 1/2 fl oz180 ml
2/3 c.5 fl oz5 1/4 fl oz150 ml
1/2 c.4 fl oz4 1/4 fl oz120 ml
1/3 c.2 1/2 fl oz2 1/2 fl oz75 ml
1/4 c.2 fl oz2 fl oz60 ml
1/8 c.1 fl oz1 fl oz30 ml
1 tablespoon
(1 tbsp)
1/2 fl oz1/2 fl oz15 ml

As you can see from the table, the difference between US and UK imperial systems becomes more obvious – and more important – as the quantities increase. For smaller measures, the differences are tiny.

So, for larger quantities:

US/UK Larger Quantity Weight Conversions

US Customary SystemUK Imperial SystemMetric
5 fl oz5 fl oz
(1/4 pt)
150 ml
10 fl oz10 fl oz
(1/2 pt)
300 ml
15 1/4 fl oz15 fl oz
(3/4 pt)
450 ml
20 1/4 fl oz
(1 1/4 pint - pt)
20 fl oz
(1 pt)
600 ml
1 1/2 pt1 1/4 pt750 ml
2 1/8 pt1 3/4 pt1000 ml
(1 litre)
2 1/2 pt2 pt1.2 litres (l)
3 1/8 pt2 1/2 pt1.5 l

Some utensils can be measures in their own right.

Nowadays, many recipes make references to measures such as tablespoons or teaspoons etc.  When I began cooking with my mum as a child, I had assumed that these names actually referred to the utensil!  I hadn’t appreciated that they are specific measurements in their own right.

So, the following list of measurement units defines what these are:

Tablespoon (tbsp).  A 15 ml measuring spoon (or ½ oz water).   This measure is used all the time in cooking.  But also used to measure quantities of medicine, such as Calpol.  It’s often used for other preparations too.

Dessertspoon (dstsp).  A 10 ml measuring spoon.  Some older recipes refer to half a tablespoon (¼ oz water) but 10 ml is the modern measure.

Teaspoon (tsp).  A 5 ml measuring spoon.

A drop.  A very vague but descriptive measure!  This differs depending on the liquid and the dropper/bottle top.

A pinch.  Another vague one.  A quantity small enough to hold between thumb and forefinger.  Apparently, it’s usually about ⅟16 of a tsp.

Approximate weights for everyday ingredients

There are certain everyday ingredients where it’s useful to know an approximate weight. In the book, ‘How to Eat’, Nigella Lawson recommends familiarity with the following:

measuring spoons picture
Image by Henrik Larsen via Pixabay
  • Citrus fruit:
    • 1 lime 1 tsp zest or 2 tbsp (30 ml) juice
    • 1 lemon 2 tsp zest or 8 tbsp (120 ml) juice
    • 1 orange 1 tbsp zest or 10 tbsp (150 ml) juice
  • Garlic 1 clove = 1 tsp
  • Onion 1 onion = 130g
  • Nuts in shells =  unshelled weight x 2
  • Peas/beans:
    • Peas in pod = podded weight x 3
    • Broad beans in pod = podded weight x 3
  • Shellfish 10 palourdes clams = 154 g 
  • Mussels 30 mussels = 500 g
  • Rhubarb 800 g untrimmed = 475 g trimmed = 275 g puréed (when cooked with sugar)

It’s obviously really really useful to have measuring implements, such as jugs, cups and spoons in your kitchen.  Helpfully, measuring spoons are often sold in sets. And other implements, such as jugs, can have a dual scale for both imperial and metric measures.

Personally, I find the UK metric system the most simple system to use in everyday cooking. This is especially so in baking, where weighing ingredients to rounded figures produces a much better outcome. But, I can accept that this maybe because I have been using it for so long.

The metric system was started in France.

Interestingly, I’ve used the term ‘UK metric system’ throughout this blog. I did this to keep things simple. However, the metric system actually comes from France.

The metre (or meter, for those in the US) is the basis for the metric system. One metre is equal to one ten-millionth of the shortest distance from the North Pole to the Equator, measured along the meridian passing through Paris, France.   Nowadays though, there’s a far more technically accurate definition involving wavelengths but I think the original one is far more fun.

Please print off, laminate and use the pdf tables to make your life easier.  No more frantic Googling…

 
Which units of measurement do you use? Have you experimented with mixing and matching conversion units?  What happened? Do you cook without using measurements? How do you do it? Are there any other differences worth mentioning?


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4 thoughts on “How much is a cup in ml? [And other cooking measurement questions.]”

  1. Hi Rachael, this is an excellent post, which I thoroughly enjoyed reading. I have often been bamboozled by the different measuring facilities. And why, oh why, does the US persist with cups? You pointed out these aren’t even accurate! Goodness knows how they managed to get so successful with their American Apple Pie! Thanks again for a good read, Alice

  2. Philippa FitzGerald-Finch

    I love this blog. Informative, useful and written in a humorous way. Living at 3,500 feet above sea level in Canada adds to the challenges of baking as both the amount of liquid used and the temperature and cooking time sometimes need adjustment. After 40 plus years of trying I have yet to make a Yorkshire Pudding that does not resemble a hockey puck.
    Any suggestions would be gratefully received!

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