Spreadsheets of the Japanese Adjectives Conjugations

Below you can find spreadsheets of the conjugations of most common Japanese adjectives with furigana. The files are in the .xlsx (with Excel you can view the furigana by enabling the phonetic guide) and in .pdf. formats. Unfortunately the furigana or the phonetic guide are not available with Google Sheets yet.

1.1 い-Adjectives Conjugaison



1.2 な-Adjectives Conjugaison




In i-adjectives, it seems like informal past is just copied from informal negative non past, and informal negative past is missing the negative part 「な」.

Na-adjectives’ columns aren’t labeled properly, and you’re missing は in the negative long form: ではありませんでした.

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Wouldn’t it be better to simply learn the conjugation rules? You can learn them in a day and then you can conjugate (mostly) every い-adjective in existence rather than relying on a document limited to 207 words.


Thank you for you revision. I will correct it.
There is a typo in the title as well.

Yes. Should be 危なかった

Sure, but it always good to have a reference. There are some exceptions as well.

But is it actually good to have a reference? If making a reference, would it not, again, be better to make a reference simply explaining how to conjugate adjectives rather than a finite list of adjectives with no explanation? You can count on one hand, maybe half a hand, the exceptions needed to learn, so someone learning would be infinitely better served properly learning the foundational い/な rules plus some exceptions, and then never again in their entire life need to worry about figuring out how to conjugate an adjective.


Could I ask for some examples? In my nearly 5 years of Japanese, I can’t think of any instance in which I’ve seen an exception to the い- and な-adjective rules. There are verb exceptions to look out for, for sure, but for adjectives? Perhaps I’m just not remembering something…

(For reference – and I’m not saying this to boast, because I sincerely think I still have much to learn – I have an N1 and regularly write formal emails in Japanese.)

EDIT: If you’re talking about adjectives ending in い that actually are な-adjectives, I’d call that a matter of learning the right categories for new adjectives. I’ve been asked to teach a class on adjectives by my teachers two years in a row, and my approach was to highlight the fact that な-adjectives can often be written as 100% kanji, though that’s not always true.

EDIT 2: Oh wait… what, いい?


Yeah, I think いい is the only real irregular adjective. (Wikipedia mentions a few instances of subtle stuff involving adj + め or adj + すぎる being a bit irregular in a few cases, but that’s not really what I think of when I think of adjective conjugation…)


I think I saw something a fairly regular rule for 〜すぎる, but I definitely don’t think it’s universal. I’ll need to look it up.

It’s true that people say こいめ and not こめ though (maybe just to avoid mixing it up with こめ=rice).

Anyway, I don’t want anyone to misunderstand that I’m here to be snarky or haughty. I just sincerely think that it might be better to make use of the fact that Japanese conjugation rules are actually very uniform here. References are good for practice and seeing the rules in action, but learning the rules will probably help you the most. Japanese is not like French, where dictionaries list around 70 possible conjugation models and you just have to learn them all – in Japanese, the rules work, most of the time. (I’m not saying this as a jab at French, which I’ve loved for a long time and am fluent in.)

Here’s are some screenshots from a document I made (and which I once posted on Twitter). All conjugated forms can be derived from these basic stems (I gave them non-technical names as much as possible for the sake of everyone’s comprehension):

The one exception:

As for the past tense specifically (which features a lot in your tables), here is the etymology, which should make remembering it much more logical if you know how to conjugate ある:

In other words, for い-adjectives, just take the adverbial form (〜く), add あった, and then blend くあ into か. That’s why it’s 〜かった (〜く+あった→〜かった). For な-adjectives, both 〜だった and 〜であった are valid, and they are related by the same phenomenon – two syllables blending into one (〜で+あった→〜だった) .

For the negative past forms, all you need to do is to apply the rules above to ない as if it’s an い-adjective. That should help you avoid accidental trailing 〜くs in the middle of the word.


Well, in my eight years experience in studying Japanese and from my living in Japan, I think it is better to know by heart than just think about the rule. Seeing it with different adjectives can help in memorising the rule. I think it might help in reaching fluency in Japanese. I did not see it anywhere else except at the end of A Dictionary of Basic Japanese Grammar.

In French, we learn the verb tenses by heart, the same is true for irregular verbs in English or Germans. Similarly in Latin or Ancient Greek for declinations.
We know from the sound, if a tense is wrong.

It is true that it makes less sense than for the godan verbs. I did it for verbs so I thought it might be logical to do it for adjectives as well. I have a list of adverbs as well.

I agree – I think knowing the rule while not knowing how to apply it is useless – but there are other ways to see these things happening to various adjectives (reading, watching shows, writing sentences etc.). I’m not against practising conjugation with different adjectives to see how it works, but I think trying to learn the rule once (no need for it to be perfect – I’m talking about awareness) and then practising is more helpful because that way you have something to refer to all the time. In short, my approach is ‘learn about the pattern, then practise and look out for the pattern so you remember it’.

I’m very surprised, because I think I’ve seen the rules in many Japanese textbooks. However, yes, I’ve seen people who study with those textbooks and still struggle with adjective conjugation. That means that practice is also important.

To some extent, yes, but for example, in French, a lot of verb forms sound exactly the same. Knowing how they sound doesn’t always fix all the problems (and these homophones are also the source of most French spelling mistakes).

More generally, I see what you mean about knowing whether or not something sounds wrong, but since in Japanese the endings almost always sound the same for each adjective type, and they are all spelt the same on paper, well… that’s why I think starting with the rule (again, no need for perfect memorisation) and then practising (to remember better) is easier.

However, maybe you find this helpful! If that’s the case, do whatever practice you feel helps you remember. My preference for using the rules in this case is a result of the patterns I’ve seen in Japanese. Either way, I’m someone who doesn’t like rote memorisation without understanding, and even in French, I’ve looked for (and found) patterns that link large groups of verbs to help me remember things. I find that patterns and explanations help me remember things faster. That may not be true for you – I have a friend who prefers to learn things one at a time instead of learning a general rule – in which case you should work with what you find useful.


I think that’s true often enough, fortunately.

いい → よく

But even that is hardly an exception, because 良い is よい.

When I started learning Japanese seriously some 2.5 years ago I did have sheets of verb and adjective conjugations, but these become way less useful after being exposed to Japanese for long enough and just getting the different conjugations into my head.


な-adjectives that end in な can also be a bit confusing, like 頑な…


Have to say I’ve never heard this one, but good to know. Thanks! (And yeah, it’s kinda confusing because it’s so unexpected.)

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You can use the spreadsheet to make an app to practice conjugation. Unfortunately, I do not enough time to do it.

thank you! I am amazed to look at the sheets. A bit overwhelming, I only looked at the A thru E… wow

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It tends to trip me up particularly in the adverbial form 頑なに, where my brain seems to want to read it as 頑 + なに. But the なな when it’s attached to a noun is a bit odd looking too.


I have updated the spreadsheet and pdf with the corrected version for the い adjectives.

I know there was discussion of いい, but what were the other exceptions?

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