In short

The partitive is just di + the definite article (del pane, della carne, dei libri, degli amici) used to mean “some”. In the plural it is the missing plural of un/una - un libro -> dei libri. The B1 skill is not building it (step 7 already did that) but knowing when to leave it out: negatives and quantity expressions kill it - Non ho soldi, un chilo di pane.

The rule

The partitive marks an indefinite quantity: some of a substance, or an unspecified handful of things. Same forms as the combined prepositions, completely different job.

Step 1 - Build it from the article the noun already wants. Take the noun, pick its definite article exactly as always (il / lo / l’ / la / i / gli / le), then fuse di onto it. Nothing new to memorise - this is the di row of the table in Prepositions, simple and combined with the article.

il pane -> del pane. lo zucchero -> dello zucchero. l’acqua -> dell’acqua. gli amici -> degli amici. Get the article right and the partitive is automatic. This is why it is degli amici and never dei amici: amici takes gli.

Step 2 - Know which of the two jobs you are doing. The singular and the plural are not the same tool.

• Singular, uncountable: del pane = some bread, a certain amount of bread. It answers “how much”, loosely.
• Plural, countable: dei libri = some books, a few books. Here it is doing something Italian otherwise cannot do at all - un libro has no plural, so dei libri fills the gap. Ho un amico -> Ho degli amici.

That plural is the one to internalise. Where English says “I invited friends” with a bare plural, Italian much prefers Ho invitato degli amici.

Step 3 - Drop it whenever the sentence already carries the quantity. This is where the marks are lost. The partitive disappears - not optionally, but properly - in four places:

• Under negation. Non ho soldi. Non bevo vino. Non c’è pane. A negative already says “zero”, so “some” has nothing to do. Non ho dei soldi is the single most common error here.
• After the preposition di. Ho bisogno di consigli. Parliamo di politica. Two di in a row collide, so the partitive gives way. Never di dei, di del.
• After an expression of quantity. un chilo di mele, una bottiglia di vino, un bicchiere d’acqua, molta gente, tre libri. The quantity word already did the measuring.
• In lists, notes and signs. Compra pane, latte e uova. Enumerations run bare - a shopping list does not need “some” on every line.

Step 4 - Elsewhere, it is genuinely optional. In a plain affirmative sentence both work: Ho comprato pane and Ho comprato del pane are both correct Italian. The difference is light: the bare noun is neutral and generic (“I bought bread”), the partitive nudges towards a quantity (“I bought some bread”). Nobody will misunderstand you either way, so spend your attention on Step 3, which is not optional.

Step 5 - Choose between the partitive and the step 22 quantifiers. del pane, un po’ di pane, qualche libro, alcuni libri overlap heavily. Practical division:

• Uncountable: del pane = un po’ di pane. un po’ di insists a bit more on a little; del is the neutral default.
• Countable plural: dei libri = qualche libro = alcuni libri. The partitive is the most common in speech, alcuni sounds slightly more written, qualche is the one that traps you into a singular noun.
• After a negative, none of them: Non ho libri.

Forms & patterns

The forms - di + the definite article, and nothing else:

Which one your noun takes:

Singular vs plural - two different jobs:

Use it or drop it:

Competing with the step 22 quantifiers:

Examples

Common mistakes

• Non ho dei soldi. -> Non ho soldi. A negative sentence has no “some” to express. Drop the partitive after non every time - this is the error that marks the level.
• Ho bisogno di dei consigli. -> Ho bisogno di consigli. The verb already brings its own di. Two di never stack, so the partitive stands down.
• Ho comprato un chilo di del pane. -> Ho comprato un chilo di pane. un chilo di is already the quantity. Same for una bottiglia di vino, un bicchiere di acqua.
• Ho visto dei amici. -> Ho visto degli amici. amici takes gli, so the fused form is degli. The partitive inherits the article’s sound rules - see Definite and indefinite articles.
• Ho mangiato delle pane. -> Ho mangiato del pane. pane is masculine singular and takes il, so di + il = del. Choose the article for the noun first, fuse second.

Tips

• It is not a new form - it is the di row you already know. If you can say del tavolo (of the table), you can say del pane (some bread). Identical word, different job; only context tells them apart, and context always does.
• dei / degli / delle is the plural of un / una. Learn the pair as a swap: un problema -> dei problemi, un amico -> degli amici. English drops the word entirely in the plural, which is exactly why learners forget it exists.
• non and di are the two off switches. Non ho pane, Ho bisogno di pane. If either word is in the sentence, the partitive is gone. Everything else is a matter of taste.
• When in doubt in the singular, un po’ di is always safe. un po’ di pane works wherever del pane does and costs you no decision about gender or article.