The type 0 conditional (sometimes called the "zero conditional") is the simplest of the Spanish si-clause patterns. It describes situations where the result is always guaranteed — laws of nature, definitions, automatic reactions, and unchanging habits. If A happens, B happens. Every time.
The structure
Both halves of a type 0 conditional sit in the present indicative. The si-clause sets up the condition; the result clause states what inevitably follows.
Structure: Si + present indicative, present indicative.
Si llueve, me mojo.
If it rains, I get wet.
There is nothing hypothetical here. The speaker is not imagining anything — they are stating a fact that holds up every single time the condition is met.
Natural laws and science
Type 0 is the default pattern whenever you want to state a physical, chemical, or biological rule. It is the form you will see in textbooks, instructions, and explanations of how things work.
Si mezclas azul y amarillo, obtienes verde.
If you mix blue and yellow, you get green.
Si las plantas no reciben luz, mueren.
If plants don't get light, they die.
Habits and routines
The zero conditional is also perfect for describing what somebody (or something) habitually does in a given situation. The present tense in both halves emphasizes that this is the speaker's normal, predictable behavior.
Si tengo hambre, como una manzana.
If I'm hungry, I eat an apple.
Si mi hermano llega tarde, mi mamá se enoja.
If my brother arrives late, my mom gets angry.
Si hace frío, nos ponemos un suéter.
If it's cold, we put on a sweater.
Each of these could be rewritten with cuando ("when") without changing the meaning. The speaker is describing a pattern that repeats itself whenever the trigger appears.
Definitions and rules
When you need to explain how something works — a rule of a game, a classroom policy, a workplace norm — the type 0 conditional is the natural choice.
Si el semáforo está en rojo, los carros se detienen.
If the traffic light is red, cars stop.
Type 0 vs. type 1
It is easy to confuse the zero conditional with the type 1 conditional, which also uses the present in the si-clause. The difference is in the result clause and in the meaning:
| Type | Result clause | Meaning |
|---|---|---|
| Type 0 | present | always true |
| Type 1 | future / imperative | probable in the future |
Compare:
Si llueve, me mojo.
If it rains, I get wet. (general truth)
Si llueve, me voy a mojar.
If it rains, I'm going to get wet. (this specific occasion)
The first sentence is a general statement about the speaker. The second refers to a specific rainy afternoon that is probably coming.
Word order
The two halves can appear in either order. When the si-clause comes first, it is followed by a comma; when the result clause comes first, no comma is needed.
Me mojo si llueve.
I get wet if it rains.
Both orders are equally natural in Latin American Spanish, and neither one changes the meaning. Choose whichever one emphasizes the part of the sentence you care about most.
Related Topics
- Type 1: ProbableB1 — Use a present-tense si-clause with a future, imperative, or present result clause for situations that are likely to happen.
- Type 2: ImprobableB2 — Pair an imperfect-subjunctive si-clause with a conditional result clause for hypothetical or unlikely present situations.
- Other Conditional ExpressionsB2 — A family of conjunctions — a menos que, con tal de que, en caso de que, and more — all express conditions and all require the subjunctive.