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'Rational' is the adjective meaning based on logic; 'rationale' is the noun for the reasoning behind a decision.
Side-by-side comparison
"Rational" (adjective) describes something based on reason and logic, not on emotion. "A rational decision" = a well-reasoned, logical decision. The opposite of "irrational".
A rational approach to the problem requires setting aside personal feelings and focusing on the data.
It is not always rational to choose the cheapest option, quality and long-term cost matter too.
She remained calm and rational throughout the crisis, which helped steady the rest of the team.
"Rationale" (noun) is the underlying reason or justification behind a decision or plan. "The rationale for the change" = the logical reasons explaining why the change was made.
The CEO presented the rationale for the merger in a company-wide address that lasted two hours.
Before approving any budget request, the committee requires a clear rationale from each department.
There was no obvious rationale for the policy change, which frustrated staff across all divisions.
Common mistake
- •"Please explain the rational behind your proposal" is wrong (correct: rationale, the noun meaning the reasoning).
- •"Rational" is always an adjective and cannot function as a noun in this sense.
Trick to remember it
- •"RationAL" ends in -AL like "logicAL," "practicAL," "criticAL", all adjectives.
- •"RationalE" adds an E, the E stands for Explanation: it IS the reasoning/justification itself.
Quick rule
- •Is it the adjective describing something based on reason? "Rational".
- •Is it the noun meaning the reasoning or justification? "Rationale".
Did you know?
The confusion between the two is especially common in the contexts where both are most used: academic writing, business reports, and legal documents. A pronunciation note: RATIONALE sounds like /ˌræʃəˈnɑːl/ in English, it rhymes approximately with "national ale."
Practise what you learned
Exercise 1 · Pick the right one
His decision to leave early was completely _____ given how tired he was.
Exercise 2 · Pick the right one
Could you explain the _____ behind the new company policy?
Exercise 3 · Form the word
Related word pairs
"Above" is at a higher level without contact; "over" implies covering, movement, or crossing.
'Currently' means 'at the present time'; 'actually' means 'in reality', not 'nowadays'.
"Actually" corrects or contrasts an assumption; "really" intensifies or confirms.
'Adopt' means to take something on as your own; 'adapt' means to adjust to something new.
Bryan López
Founder of SpeakUP Academy