Specifying the difference
When comparing two things, Polish explicitly states the margin of difference using the preposition o ("by") followed by the Accusative case.
The phrase describing the margin can be placed either right before or right after the comparative adjective.
| My brother is five centimeters taller than father. | Mój brat jest o pięć centymetrów wyższy niż ojciec. |
| My sister is younger by two years. | Moja siostra jest młodsza o dwa lata. |
Measuring with units
For a margin of exactly one unit (like a single gram or meter), use o followed by the singular noun. Since units like gram, metr, and centymetr are inanimate masculine nouns, their Accusative form is identical to the Nominative.
| This ring is one gram heavier. | Ten pierścionek jest o gram cięższy. |
| This passenger car is a meter narrower. | Ten samochód osobowy jest o metr węższy. |
With larger numbers, the number takes the Accusative (usually identical to the Nominative), and the noun follows normal counting rules (e.g., taking the Genitive plural for 5 and above).
| The reduced ticket is ten zlotys cheaper. | Bilet ulgowy jest o dziesięć złotych tańszy. |
Saying "much" more
To emphasize a large but inexact difference, use the fixed phrase o wiele ("much" or "by a lot"). It usually sits right in front of the comparative adjective.
| This building is much taller. | Ten budynek jest o wiele wyższy. |
| The English language course is much more expensive. | Kurs języka angielskiego jest o wiele droższy. |