Changing Portions or Servings
Changing Portions or Servings
To do Recipe Convenversion due to wanting to change portions or serving sizes of a Recipe first we note the portions/servings of the orignal recipe and the portions/serving of the new recipe we would like to make.
In the example above, the Original Recipe has 10 Portions (Cookies) and the New Recipe has 15 Portions (Cookies).
Now we divide our New Recipe Portions by the Original Recipe Portions. So 15 / 10 = 1.5
Therefore to do the Recipe Conversion you need to multiply all the original recipe ingredient quantities by 1.5.
For example if the original recipe says 100 grams of sugar, then 100 grams multiplied by 1.5 = 150grams. So you need 150grams in your new recipe. As you can see Recipe Conversion for portions iszes is fairly simple.
Unit Conversion
Imperial to Metric and Metric to Imperial Weight Conversion
To convert weights and measures from Metric to Imperial or Imperial to Metric all we do is multiply by the appropriate factor. The table below shows the conversion factors to use.
To Convert  Multiply By 

Pounds (lb) to grams (g)  453.6 
grams (g) to Pounds (lb)  0.002205 
Pounds (lb) to KiloGrams (kg)  0.4536 
kilograms (kg) to Pounds (lb)  2.205 
Ounces (oz) to grams (g)  28.35 
grams (g) to Ounces (oz)  0.03527 
Example
To convert 4 pounds (lbs) to grams we multiply by 453.6 and get 1814.4 grams. (4 * 453.6 = 1814.4)
Things get a little tricky if you have a weight in pounds and ounces. First multiply the pounds value to grams, then multiply the ounces value
to grams and add the two results to get your final answer.
Imperial to Metric and Metric to Imperial Lengths
Occasionally you may need to do Recipe Conversion on lengths of ingredients. Here are the Conversion Factors
To Convert  Multiply By 

Inches (“) to Centimetres (cm)  2.54 
Centimetres (cm) to Inches (“)  0.394 
Inches (“) to MilliMetres (mm)  25.4 
MilliMetres (mm) to Inches (“)  0.039 
Make Recipes to Fit Pans, Tins and trays
Recipe conversion sometimes requires some simple mathematics. The mathematics of converting a square or circular baking tray or tin to a larger diameter aren’t so straight forward. To do this try of Recipe Conversion follow the simple steps outlined here.
Changing for Square or Rectangular Items
For Square or Rectangular Recipes the following Recipe Conversion can be used.
Note: This calculation assumes you want to keep the height/depth of the cake/pizza/loaf/whatever the same. If you do not you will have to further multiply by the depth also and think about changing cooking times.
Before we can do the Recipe Conversion we need to know the width and length of the original recipes tin/pan/pot and the width and length of the new recipes tin/pan/pot. The Width is across one side of the rectangle and the Length is across the other side of the rectangle, it doesn’t really matter which way round you measure it as long as you don’t measure the height.
Example
Original Recipe Length = 23 Inch, Width = 13 Inch
New Recipe Length = 28 Inch, Width = 15 Inch
All measurements must use the same measurment scale. The above example uses all inches.
The next stage of this Recipe Conversion is to calculate the area of each Recipes rectangle.
To calculate the area we simply multiply the Length by the Width (Area = Length * Width)
So the Orignal Area will be 23 * 13 = 299
We now calculate the area of the New Recipe, this will be 28 * 15 = 420
And next we divide our new area by the old area. 420 / 299 = 1.4
Therefore to do the Recipe Conversion you need to multiply the Original Recipe quantity by 1.4.
For example if the Original Recipe says 100grams of Sugar. Then 100grams * 1.4 = 140grams. So you need 140grams in your new recipe.
Changing the Recipe for Circular Items
For Cakes and Pizza the following can be used.
This calculation assumes you want to keep the height/depth of the cake/pizza/loaf/whatever the same. If you do not you will have to further multiply by the depth also and think about changing cooking times.
Before we can do this Recipe Conversion we need to know the diameter of the original recipe and the diameter of the new recipe. The Diameter is the distance across the widest part of the circle.
Example
Original Recipe Diameter = 9 Inch
New Recipe Diameter = 12 Inch
The next stage of this Recipe Conversion is to calculate the area of each Recipe.
To calculate the area we multiply the diameter by p (Area = Diameter * p)
Don’t be scared by the mathematical symbol p. The p is just the symbol for pi (no not pie but pi). Pi or p is just a mathematical constant. This means it has a value and pi’s value is 3.142 (well thats not exact but it will do for Recipe Conversion purposes). So back to calculating we replace pi or p with 3.142.
Recipe Area = Diameter * 3.142
So the Orignal Pizza Area will be 9 * 3.142 = 28.278
We now calculate the area our new recipe will have. 12 * 3.142 = 37.704
And next we divide our new area by the old area. 37.704 / 28.278 = 1.333
Therefore to do the Recipe Conversion you need to multiply the Original Recipe quantity by 1.333.
For example if the Original Recipe says 100grams of Sugar. Then 100grams * 1.33 = 133grams. So you need 133grams in your new recipe. Just multiply all the other ingredients in the same way to finsih your Recipe Conversion.
Country Difference Conversions
Recipe Conversion is sometimes required because some countries measures are different even though they have the same name. For example US Pints and fluid ounces are different to British pints and fluid ounces. The table below lists the differences in countries weights and measures.
Measure  Australia  Canada  UK  USA 

Teaspoon  5 ml  4.93 ml  
Dessertspoon  10 ml  —  
Tablespoon  20 ml  15 ml  14.79 ml  
Fluid ounce  28.41 ml  29.57 ml  
Cup  250 ml  284.1 ml  236.59 ml  
Pint  568.26 ml  473.18 ml  
Quart  1136.52 ml  946.35 ml  
Gallon  4546.09 ml  3785.41 ml 
Recipe Conversion has a simple program that makes these Conversions easier, Recipe Converter.
Recipe Conversion  US to British and British to US quick conversions.
Many US and British recipes give measurements in metric ml, in which case Recipe Conversion is not needed.
The US fluid ounce is only a little different to the US fluid ounce so for most recipes Recipe Conversion is unnecessary and they can be considered the same.
The US teaspoon and tablespoons are only a little different to the British metric teaspoon and tablespoons so again for most recipes Recipe Conversion is unnecessary and they can be considered the same. The only issue here is if the units are actually imperial tablespoon (17.7581714 ml) or imperial teaspoon (5.91939047 ml).
US and British pints do differ quite a lot, US=473.18 mL British=568.26 ml. The table below shows the direct conversion factors to use.
To Convert  Multiply By 

US pints to British pints  1.2 
British pints to US pints  0.83 
The US cup is 8 US fluid ounces (fl oz) or 236.59 ml. The British cup is 10 British fluid ounces (fl oz) or 284.1 ml. Therefore the British cup is approximately one fifth greater than the US equivalent. The table below shows the conversion factors to use to directly convert between the two.
To Convert  Multiply By 

US Cups to British Cups  1.2 
British Cups to US Cups  0.83 
So the Recipe Conversion for a British recipe containing 5 British Cups would equal 5 * 0.83 = 4.15. Recipe Conversion need not be this exact so we just say 4 and a bit cups.
Change to More Useful Units
This Recipe Conversion method will allow you to convert any weight/mass, volume or length ingredient unit into any other ingredient unit. The method works by giving you the conversion factor for a common unit (metric), you can then convert from that unit back into any other unit.
Recipe Conversion  Weight / Mass Conversion
To convert any Weight measure in to any other other weight measure first convert it to grams and then convert it to the desired unit.


Example: To convert 10 Pounds (lb) to milligrams (mg) using this method, first convert 10 Pounds to grams, 10 * 453.59 = 4535.9 Next convert 4535.9 grams into milligrams, 4535.9*1000 = 4535900mg.
If you would like a program that does all the hard work for you, you can download one free here Recipe Converter.
Recipe Conversion  Length Conversion
To convert any length measure into any other other length measure first convert it to grams and then convert it to the desired unit.


Example: To convert 10 Inches (“) to metres (m) using this method, first convert 10 Inches to millimetres, 10 * 25.4 = 254.0 Next convert 254 millimetres into metres, 254*0.001 = 0.254metres.
A small downloadable program is available that will make this Recipe Conversion much easier for you, you can find it here Recipe Converter.
Recipe Conversion  Volume Conversion
To convert any volume measure into any other other volume measure first convert it to millilitres and then convert it to the desired unit.


Example: To convert 1 UK pint to litres (l) using this method, first convert 1 UK Pint to millilitres, 1 * 568.26 = 568.26 Next convert 568.26 millilitres into litres, 568.26*0.001 = 0.56826 litres.
Recipe Conversion have a small downloadable program to make all this much easier for you, if you would like it click Recipe Converter.
Conversion of Oven Temperatures
Recipe Conversion is sometimes needed when you want to change from on type of oven temperature to another. There are 3 popular types of oven temperature settings used, Gas Mark, degrees Farenheit (°F) and degrees Celsius (°C).
To convert from degrees Farenheit (°F) to degrees Celsius (°C), you need to do the following calculation.
Tc = (5/9)*(Tf32)
Tc is the temperature in degrees Celsius (°C) and Tf is the temperature in degrees Fahrenheit (°F)
To convert from degrees Celsius (°C) to degrees Farenheit (°F) , you need to do the following calculation.
Tf = (9/5)*Tc+32
Tc is the temperature in degrees Celsius (°C) and Tf is temperature in degrees Fahrenheit (°F)
To make this all simpler Recipe Conversion have a small downloadable program Recipe Converter.
Recipe Conversion  Simple Oven Temperature Conversion
Neither calculation is particularly easy and for Recipe Conversion we don’t need to be so precise. Therefore we suggest you use the following tables conversions which also includes Gas Mark settings.
Gas Mark  °C  °F 

1  140°C  275°F 
2  150°C  300°F 
3  170°C  325°F 
4  180°C  350°F 
5  190°C  375°F 
6  200°C  400°F 
7  220°C  425°F 
8  230°C  450°F 
9  240°C  475°F 
For values not listed in the table use your own judgement to do the Recipe Conversion.