Four calculators for the typical kitchen questions
Four recurring problems show up in everyday cooking: converting between weight and volume, tablespoons and teaspoons as quick measures, scaling portions up or down, and dough ratios in baking. Each case has its own tool:
| Calculator | Typical question |
|---|---|
| Grams/ml calculator | 200 g of honey is how many ml? And the other way? |
| Tablespoon/teaspoon calculator | How many grams are 3 tablespoons of flour? |
| Recipe converter | Scale a recipe for 4 portions to 7 |
| Pizza dough calculator | Water, salt, yeast in baker's percent |
Grams, ml and density – why 1:1 almost never works
The most important rule in the kitchen: weight is not volume. A gram is a mass, a millilitre is a volume. The two are linked by density:
- Density = mass ÷ volume
- Mass = volume × density
- Volume = mass ÷ density
For water the density is by definition 1.00 g/ml (at 4 °C). For every other ingredient it differs. A selection of the most common kitchen ingredients:
| Ingredient | Typical density (g/ml) |
|---|---|
| Water | 1.00 |
| Milk (whole) | 1.03 |
| Cream | 1.01 |
| Cooking oil | 0.92 |
| Flour (type 405, sifted) | 0.55 |
| Sugar (granulated) | 0.85 |
| Brown sugar | 0.93 |
| Icing sugar | 0.56 |
| Salt (fine) | 1.20 |
| Honey | 1.42 |
| Maple syrup | 1.33 |
| Rolled oats | 0.40 |
| Rice (uncooked) | 0.78 |
| Butter (room temperature) | 0.91 |
The practical rules of thumb that follow: 100 g of flour equals about 182 ml, 100 ml of honey weighs about 142 g, 100 g of cooking oil equals about 109 ml. With a kitchen scale you can avoid these conversions systematically; if you cook with measuring cups, keep at least the rough densities in mind. The grams/ml calculator takes care of the conversion for a selection of common ingredients.
Tablespoons, teaspoons and the question of cups
Three household measures are common in everyday cooking:
| Unit | Volume | Equivalent |
|---|---|---|
| 1 tablespoon (tbsp) | 15ml | 3 teaspoons |
| 1 teaspoon (tsp) | 5ml | – |
| 1 cup (DE) | 250ml | 16⅔ tbsp |
| 1 cup (US) | 240ml | 16 US-tbsp |
| 1 glass of water | 200ml | – |
English-language recipes additionally use pints, quarts, ounces (oz) and fluid ounces (fl oz). For US recipes the following are worth remembering: 1 fl oz = 29.57 ml, 1 oz (mass) = 28.35 g, 1 lb = 453.6 g.
In baking, care while measuring matters. A level tablespoon of flour weighs about 8 g, a heaped tablespoon can weigh 15 g or more. Anyone reproducing a recipe exactly should either always level off or switch to a kitchen scale altogether. The tablespoon/teaspoon calculator factors the density of the ingredient into the weight figure.
Scaling portions: linear and non-linear cases
Scaling recipes is mostly linear:
- Factor = target portions ÷ original portions
- New amount = old amount × factor
Example: a recipe for four serves needs 200 g flour, 100 g sugar, 2 eggs, 1 tsp baking powder. For six (factor 1.5) this becomes 300 g flour, 150 g sugar, 3 eggs, 1½ tsp baking powder.
For many ingredients this works without issue. Non-linear cases include:
- Yeast: a larger dough does not need 1.5× the yeast; often the same or slightly less is enough because more mass can rise longer.
- Spices: at double quantity, double seasoning is rarely optimal. Rule of thumb: 1.5× seasoning at double quantity.
- Salt in dough: stays proportional to the flour, not to the total mass.
- Baking time: a doubled cake doesn't bake twice as long, usually only 15–25 % longer, provided the height matches.
- Cake tin size: a Ø 26 cm tin does not have twice the area of a Ø 18 cm tin. Recipe amounts must follow the area ratio.
Area factor between two round tins: F = (Ø₂)² ÷ (Ø₁)². A 26 cm tin compared with a 22 cm tin has a factor of 26² ÷ 22² = 676 ÷ 484 ≈ 1.40.
The recipe converter scales linearly and gives clear notes on the non-linear special cases.
Baking with baker's percentages
In bakeries and ambitious home baking, baker's percentages are common. The flour weight is always 100 %, every other ingredient is expressed as a percent of that. Typical values for a classic pizza dough:
| Ingredient | Share (baker's percent) |
|---|---|
| Flour | 100 % |
| Water | 60 to 70 % |
| Salt | 2 to 3 % |
| Yeast (fresh, long ferment) | 0.1 to 1 % |
| Yeast (fresh, short ferment) | 2 to 3 % |
| Olive oil (optional) | 0 to 5 % |
With 500 g of flour at 65 % hydration this gives 325 g of water, 12.5 g of salt and – depending on the ferment – 0.5 to 15 g of yeast. The advantage of baker's percentages: the ratios stay constant regardless of dough size. The pizza dough calculator works on this logic.
Cooking times, baking times and temperatures
A pure quantity calculation says nothing about heat. Three rules of thumb:
- Thinner than 3 cm: baking time often shorter than stated, because heat penetrates fast.
- Higher than 5 cm: baking time often 10–20 % longer.
- Lower temperature, longer time = more even result for dense dough (bread, cheesecake).
- Higher temperature, shorter time = better for airy structures (pizza, rolls).
Switching from top/bottom heat to fan-forced: reduce the temperature by about 20 °C or shorten the time – usually a bit of both.
Common kitchen errors
- Measuring flour straight from the bag: compacted flour gives noticeably more weight per volume. Sift or loosely spoon it into the measuring cup first.
- Translating US recipes 1:1 into German cups: 1 US cup is not quite a German cup.
- Doubling yeast when the dough is doubled: usually wrong – more mass relatively needs less yeast, because it can ferment longer.
- Scaling salt against the total mass: in bread and pizza dough, salt is referenced to the flour, not the total weight.
- Not preheating the oven: for yeast and puff pastry doughs, preheating is part of the recipe.
Conclusion
Kitchen calculators work when you use the right inputs: the density of the ingredient, level or heaped measuring, linear and non-linear scaling. With the four calculators on Ultra-Rechner you have the tools to convert quantities cleanly – and the tables above let you keep the most important rules of thumb in your head before you even click.
Sources
- BLE – Federal Office for Agriculture and Food, density values – ble.de
- DLG – German Agricultural Society, baked goods guidelines – dlg.org
- USDA FoodData Central – ingredient and density tables – fdc.nal.usda.gov