Preciso vs. exacto

In Spanish, the words 'preciso' and 'exacto' are often used to mean 'exact' or 'precise', but they have different nuances and uses. Understanding the difference between these two words can help in using them correctly.

Preciso

The word 'preciso' generally means something necessary, accurate, clear, or required, but it can also mean precise or exact in some contexts.
Es preciso que llegues a tiempo.
(It is necessary for you to arrive on time.)
Necesito una descripción precisa del lugar.
(I need an accurate description of the place.)
La medición debe ser precisa.
(The measurement must be precise.)

Exacto

The word 'exacto' specifically refers to something that is exactly correct or without deviation. It emphasizes absolute accuracy and correctness.
La respuesta es exacta.
(The answer is exact.)
Necesito el número exacto de asistentes.
(I need the exact number of attendees.)
El reloj marca la hora exacta.
(The clock shows the exact time.)

Summary

In summary, while both 'preciso' and 'exacto' can mean precise or exact, 'preciso' emphasizes necessity and accuracy in a broader sense, whereas 'exacto' refers to something that is completely correct and without deviation.