1 porcja, 2 porcje, 5 porcji: Scaling Recipes and Handling Polish Plurals With Intl.PluralRules

A "servings" slider looks like the easiest feature on a recipe site: multiply every quantity by a factor. Then you ship it in Polish and discover two things — scaling has real-world edge cases, and Polish has three plural forms for counted nouns (plus one for fractions).

Kuchnia Przepisy is a Polish recipe site covering dinners, cakes (serniki, szarlotki, no-bake cakes), soups, and modern categories like air fryer, Thermomix/Lidlomix and high-protein recipes. Here's how to scale recipes properly and label them correctly in Polish.

Store quantities as numbers, not strings

"2 szklanki mąki" can't be scaled. Store structure, render text:

interface Ingredient {
  qty: number | null;       // null for "sól do smaku" (salt to taste)
  unit: "g" | "ml" | "szt" | "łyżka" | "łyżeczka" | "szklanka" | null;
  name: string;             // "mąka pszenna"
  scalable?: boolean;       // false for e.g. "1 blacha" or a pinch
}

Scale — then round to something a person can measure

Multiplying 3 eggs by 1.5 gives 4.5 eggs. Nobody measures 4.5 eggs, or 187.5 g of flour to the gram. Round by unit:

function roundFor(unit: Ingredient["unit"], x: number) {
  switch (unit) {
    case "szt": return Math.max(1, Math.round(x));      // whole items (eggs)
    case "g": case "ml": return x < 50 ? Math.round(x) : Math.round(x / 5) * 5;
    case "łyżka": case "łyżeczka": case "szklanka": return Math.round(x * 4) / 4; // quarters
    default: return x;
  }
}

export function scale(list: Ingredient[], from: number, to: number) {
  const f = to / from;
  return list.map((i) =>
    i.qty == null || i.scalable === false ? i : { ...i, qty: roundFor(i.unit, i.qty * f) }
  );
}

Baking scales by pan area, not servings

Many cakes are written for a baking tray ("12 porcji z blachy") or a round tin. Doubling servings doesn't mean doubling the tin — scale by area:

const rectArea = (w: number, h: number) => w * h;
const roundArea = (d: number) => Math.PI * (d / 2) ** 2;

// 24 cm round tin -> 26 cm round tin
const factor = roundArea(26) / roundArea(24); // ≈ 1.17

Baking time doesn't scale linearly, so the UI suggests checking earlier or later instead of recalculating it.

Polish plurals: one, few, many — and other

English has "1 serving / 2 servings". Polish uses different forms depending on the number:

• 1 → porcja
• 2–4, 22–24, 32–34… → porcje
• 0, 5–21, 25–31… → porcji
• fractions (1,5) → porcji

Don't hand-code the rules — Intl.PluralRules already knows them:

const pr = new Intl.PluralRules("pl-PL");

const PORCJA: Record<Intl.LDMLPluralRule, string> = {
  one: "porcja", few: "porcje", many: "porcji", other: "porcji",
  zero: "porcji", two: "porcje",
};

export const porcje = (n: number) =>
  `${new Intl.NumberFormat("pl-PL").format(n)} ${PORCJA[pr.select(n)]}`;

porcje(1);   // "1 porcja"
porcje(3);   // "3 porcje"
porcje(12);  // "12 porcji"
porcje(22);  // "22 porcje"
porcje(1.5); // "1,5 porcji"

The same approach works for minutes ("1 minuta", "2 minuty", "5 minut") and pieces ("1 jajko", "2 jajka", "5 jajek").

Categories as a tree

The navigation mirrors how Polish home cooks search: top-level groups like Obiad, Ciasta, Zupy and Nowoczesna, with focused subcategories (quick dinners, chicken dishes, one-pot meals, cream soups, air fryer). A recipe can live in several subcategories, so it's a tag set with a primary category for breadcrumbs and URLs — not a strict tree.

Takeaways

• Store quantities as structured data so they can be scaled.
• Round scaled amounts to measurable units; keep eggs whole.
• Scale baking by pan area.
• Use Intl.PluralRules for languages with complex plurals.

Browse the recipes at kuchnia-przepisy.pl (in Polish). Which language gave you the most trouble with pluralization?