80 grams of dry spaghetti on a kitchen scale looks like nothing. A small handful. You drop it into boiling water, wait 9 minutes, drain it - and suddenly the plate holds 200 grams. The pasta absorbed 150% of its weight in water. That multiplier catches people off guard every single time, and it is why "enough for four" often turns into "enough for six with leftovers" or "not enough, order a side".
The same kind of gap exists in coffee. A single espresso shot uses 15 grams of grounds for 30 ml of water - a 1:2 ratio. French press? Same beans, but 13 grams per 200 ml cup at medium strength - a 1:15 ratio. Seven times more diluted. And pizza? A 13-inch large has 804 cm2 of surface area. A 9-inch small has 380 cm2. The large is not "a bit bigger" - it is 2.1 times the pizza.
These are not complicated calculations. But nobody memorizes them, and eyeballing portions leads to waste, overspending, or hungry guests.
How many pizzas does your party actually need?
The formula is simple: guests times slices per person, divided by slices per pizza. But three variables change the answer dramatically.
First, appetite. Kids eat 2 slices. Adults eat 3. A hungry crowd after a football match eats 5. That alone is a 2.5x difference in pizza count.
Second, size. Most people compare pizza by diameter and assume 32 cm is "a little bigger" than 28 cm. It is not. Area scales with the square of the radius. A 32 cm pizza has 31% more surface than a 28 cm. A 45 cm has 258% more - nearly 2.6 times the food.
Third, crust. Thin crust and Neapolitan are cut into 6 slices. Classic is 8. That changes whether you need 4 or 5 pizzas for the same group.
| Guests | Appetite | Size | Style | Pizzas needed |
|---|---|---|---|---|
| 6 | Medium (3 sl.) | 28 cm / 11 in | Thin (6 sl.) | 3 |
| 8 | Small (2 sl.) | 32 cm / 13 in | Classic (8 sl.) | 2 |
| 10 | Large (4 sl.) | 32 cm / 13 in | Classic (8 sl.) | 5 |
| 15 | Medium (3 sl.) | 45 cm / 18 in | Classic (8 sl.) | 6 |
| 20 | Medium (3 sl.) | 32 cm / 13 in | Classic (8 sl.) | 8 |
The dough ingredients scale the same way. A 32 cm classic pizza needs about 353 g of dough (62% hydration). Three of those: 631 g flour, 391 ml water, 6 g yeast, 13 g salt, 19 ml olive oil.
The Pizza Calculator handles all of this: guest count, appetite level, four standard sizes plus custom diameter, four crust styles, and optional dough recipe with baker percentages.
Calculate pizza for your group
Pizza for 4 people - family dinner Pizza for 5 people - small gathering Pizza for 6 people - casual get-together Pizza for 8 people - dinner party Pizza for 10 people - birthday or event Pizza for 12 people - larger group Pizza for 15 people - office lunch Pizza for 20 people - big party Pizza for 25 people - event catering Pizza for 30 people - large eventYour French press and your espresso machine do not speak the same language
Coffee-to-water ratio is the single biggest variable in how your cup tastes. Not the beans. Not the grinder. The ratio.
The SCA (Specialty Coffee Association) standard is roughly 1:16.67 - about 60 grams of coffee per liter of water. That is the "golden ratio" for drip and pour-over methods. But espresso runs at 1:2. Cold brew concentrate at 1:8. Moka pot at 1:7. Same beans, wildly different drinks.
And then there is strength. French press at 1:20 is light and tea-like. At 1:9, it is thick, almost syrupy. The calculator lets you slide between four levels: light (1:20), medium (1:15-1:16), strong (1:12-1:13), and extra strong (1:8-1:10). For espresso and moka pot, the ratio is fixed - strength does not apply.
| Method | Ratio (medium) | Coffee per 200 ml cup | Grind | Brew time |
|---|---|---|---|---|
| French press | 1:15 | 13 g | Coarse | 4 min |
| Drip / Filter | 1:16 | 13 g | Medium | 4-6 min |
| V60 / Pour over | 1:15 | 13 g | Medium-fine | 2.5-3.5 min |
| AeroPress | 1:14 | 14 g | Fine-medium | 1-2 min |
| Espresso | 1:2 (fixed) | 15 g per 30 ml | Very fine | 25-30 sec |
| Moka pot | 1:7 (fixed) | 9 g per 60 ml | Fine | 3-5 min |
| Cold brew | 1:8 (fixed) | 25 g (concentrate) | Very coarse | 12-24 hr |
One thing that surprises people: espresso has less total caffeine than drip coffee. A single shot (30 ml) contains about 63 mg. A 200 ml drip cup? Around 95 mg. The espresso is more concentrated, but the serving is much smaller.
The Coffee Ratio Calculator covers 8 brewing methods, 4 strength levels, and 7 cup sizes from a 20 ml ristretto to a 400 ml travel thermos.
Coffee for your exact cup count
Coffee for 1 cup - solo morning brew Coffee for 2 cups - breakfast for two Coffee for 3 cups - small batch Coffee for 4 cups - family pot Coffee for 6 cups - guests visiting Coffee for 8 cups - brunch group Coffee for 10 cups - office meeting Coffee for 12 cups - full carafeThe dry-to-cooked multiplier nobody remembers
100 grams of dry pasta becomes 250 grams cooked. White rice goes from 100 to 280 grams. Brown rice: 100 to 250. Rice noodles: 100 to 200. These multipliers exist because each grain absorbs a different amount of water during cooking.
The practical effect: if you measure 80 g of dry spaghetti per person for a main course, each plate gets 200 g cooked. That is a generous serving. But 80 g as a side dish is too much - the table shows 50 g for sides and 30 g for soup.
| Product | Dry per person (main) | Dry per person (side) | Cooked multiplier | Cook time |
|---|---|---|---|---|
| Pasta | 80 g | 50 g | x2.5 | 8-12 min |
| White rice | 70 g | 50 g | x2.8 | 18-20 min |
| Brown rice | 70 g | 50 g | x2.5 | 35-40 min |
| Boil-in-bag | 50 g (1 bag/2 ppl) | 50 g | x2.5 | 15-20 min |
| Rice noodles | 70 g | 50 g | x2.0 | 5-8 min (soak) |
A detail that matters for meal prep: calories do not change after cooking. 100 g of dry pasta has 350 kcal whether raw or cooked. But per gram, cooked pasta is only 140 kcal/100 g because of the absorbed water. Nutrition labels that say "per 100 g cooked" can be misleading if you are tracking macros from dry weight.
Brown rice takes twice as long to cook as white (35-40 min vs 18-20 min), but has three times the fiber. The trade-off is real. And rice noodles are the fastest of the bunch - they do not even need boiling, just soaking in hot water for 5-8 minutes.
The Pasta & Rice Portion Calculator handles 5 products, 3 meal types, 3 appetite levels, and gives you dry weight, cooked weight, cooking time, and calorie count in one click.
Calculate portions for your group
Pasta for 2 people - dinner for two Pasta for 3 people - small family Pasta for 4 people - family dinner Pasta for 5 people - bigger family Pasta for 6 people - guests over Pasta for 8 people - dinner party Pasta for 10 people - large batch Pasta for 12 people - event cooking Pasta for 15 people - catering prepTools discussed in this article
Pizza Calculator - calculate how many pizzas you need for any group size by appetite and pizza dimensions. Optional dough recipe with baker percentages (62% hydration).
Coffee Ratio Calculator - get exact coffee-to-water ratios for 8 brewing methods from espresso to cold brew, with 4 strength levels and brewing instructions.
Pasta & Rice Portion Calculator - calculate dry weight per person for pasta, white rice, brown rice, boil-in-bag and rice noodles with cooked weight, cooking time and calories.
More cooking tools
Kitchen Measurement Converter - convert cups, tablespoons, teaspoons to grams and milliliters for 25 common ingredients using accurate density data.
Serving Size Calculator - scale any recipe to a different number of servings. Enter up to 10 ingredients and the calculator adjusts every amount proportionally.
Baking Time Calculator - calculate meat roasting time by weight for 8 cuts, adjust baking temperature between fan and conventional ovens, and convert C/F/Gas Mark.