Translation guide
The English word "probability" can refer to the mathematical concept, the likelihood of an event, or an informal sense of something being likely. In Japanese, different words and expressions are used depending on the context and level of formality.
Expressing the precise, numerical chance of an event occurring, often in academic, scientific, or technical contexts.
The standard term for mathematical probability. Used in statistics, science, and everyday talk about chances.
The probability of rain is 80%.
Please calculate the probability of this event occurring.
A formal, academic term for probability, often used in philosophy, law, or statistics. Less common in everyday speech.
The probability of this theory is high.
Talking about how likely something is to happen in daily life, without precise numbers.
The most common word for 'possibility' or 'likelihood'. It can be used in both formal and casual contexts.
The probability of success is low.
Often used for prospects or expectations, implying a reasonable chance based on some evidence.
A formal expression meaning 'there is a strong probability that...'. Used in news or official statements.
Conveying that something is probable without using a noun.
The most common way to say 'probably'. Often used with ～だろう or ～と思う.
Probably it will rain tomorrow.
A more formal version of 'probably', often used in writing or speeches.
Literally 'the probability is high that...'. Used in both casual and formal contexts.
The probability that he will be late is high.
Emphasizing that something is almost certain.
確率 (kakuritsu) is used for numerical, calculable probability, while 可能性 (kanousei) is broader and refers to possibility or likelihood in general. Use 確率 when you can assign a number or percentage; use 可能性 for more qualitative chances.
蓋然性 (gaizensei) is very formal and technical. In most everyday situations, 確率 or 可能性 are more natural.
What is the probability of winning the lottery?
There is a high probability of snow tomorrow.
Is there any probability that he will come?
The probability of it being sunny tomorrow is slim.
There is a high probability that the economy will decline.
おそらく彼は来ないでしょう。
Probably he will not come.