In Persian, the comparative adjective is formed by the addition of the postposition تر tar to the adjectives:

Whether the second term of comparison is a noun, pronoun, or numeral, singular or plural, it takes the preposition از az ‘from, of, than.’ The az-phrase variably precedes or follows the adjective immediately:

.این مداد از آن مداد سیاه‌تر است
in medād az ān medād siyāhtar ast
“This pencil is more black than that pencil.”
.این مداد سیاه‌تر از آن مداد است

.ژوبین از آرش بلندتر است
žubin az āraš bolandtar ast
“Jubin is taller than Arash.”
.ژوبین بلندتر از آرش است

.این خانه از آن یکی زیباتر است
in xāne az ān yeki zibātar ast
“This house is more beautiful than the other one.”
.این خانه زیباتر از آن یکی است

A variable comparative form for زیاد ziyād ‘much,’ instead of زیادتر ‘more,’ is بیش‌تر, which is used more profusely than زیادتر :

.هفت از چهار بیشتر است
haft az cahār bištar ast
“Seven is more than four.”
.هفت بیشتر از چهار است

A comparative adjective which is used more often for خوب xub ‘good’ is بهتر beh tar, from a different adjective, namely, به beh, which is now obsolete as an adjective. The expected form خوب‌تر is hardly ever used.

Due to the frequency of usage, these two particular comparative adjectives are almost always written attached; that is, بیشتر and بهتر, instead of بیش‌تر and به‌تر.

The most common intensifying adverb (that is, English “much”) is خیلی xeyli, which may precede the az-phrase, or the comparative adjective:

.یلدا خیلی از سوسن قشنگ‌تر است
yaldā xeyli az susan qašangtar ast
“Yalda is much prettier than Susan.”
.یلدا از سوسن خیلی قشنگ‌تر است

And, since the az-phrase can variably precede or follow the comparative adjective:

.یلدا خیلی قشنگ‌تر از سوسن است

In addition to خیلی, there are more formal words, which are used in writings, or spoken by more educated people. Some of these adverbs and adverbial phrases may be compared with (and translated as) “much” and “much, much more…” in English. Some of these adverbs and adverbial phrases are as follows (all of the above variations apply):

بسیار besiyār ‘a whole lot’:
.یلدا از سوسن بسیار قشنگ‌تر است
yaldā az susan besiyār qašangtar ast
“Yalda is much prettier than Susan.”

be marāteb ‘in succession’:
به مراتب ← یلدا از سوسن به مراتب قشنگ‌تر است
yaldā az susan be marāteb qašang tar ast
“Yalda is much prettier than Susan.”

bi andāze ‘immeasurably’:
بی اندازه ← یلدا از سوسن بی اندازه قشنگ‌تر است
yaldā az susan bi andāze qašangtar ast
“Yalda is much, much prettier than Susan.”

biš az hadd ‘more than (i.e., beyond) any limits’:
بیش از حدّ ← یلدا از سوسن بیش از حدّ قشنگ‌تر است
yaldā az susan biš az hadd qašangtar ast
“Yalda is tremendously prettier than Susan.”

biš az andāze ‘beyond any measures’:
بیش از اندازه ← یلدا از سوسن بیش از اندازه قشنگ‌تر است
yaldā az susan biš az andāze qašangtar ast
“Yalda is much, much prettier than Susan.”

بیش‌تر از آن که فکر کنی
biš tar az ān ke fekr koni
‘more than you can imagine (literally, “think”)’:

.یلدا از سوسن بیش‌تر از آن که فکر کنی قشنگ‌تر است
yaldā az susan biš tar az ān ke fekr koni qašangtar ast
“Yalda is prettier than Susan, more than you can imagine/think.”

A form of comparative adjective as از همه az hame ‘of all’ plus –tar is used in Persian, which may be compared with English ‘-set…of all’ or ‘-er than all of them.’ In this case, hame is a “generic” replacement for the true second term of the comparison; as an az-phrase, it may precede or follow the comparative adjective:

.این کتاب از همه جالب‌تر است
in ketāb az hame jālebtar ast
“This book is the most interesting of all.”
“This book is more interesting than (all) the rest.”

.ژوبین از همه بلند‌تر است
žubin az hame bolandtar ast
.ژوبین بلند‌تر از همه است
žubin bolandtar az hame ast
“Jubin is the tallest of all.”
“Jubin is taller than the rest/every body.”

If in addition to همه از a true second term of comparison is also included in the sentence, it would follow the از همه segment and is linked to it through an ezāfe construction. Because of the terminal /h/ in همه, an euphonic [-ye] intervenes; for instance:

.چلوکباب از همهٔ غذاها خوشمزّه‌تر است
celow-kabāb az hame-ye γazā hā xošmazzetar ast
.چلوکباب خوشمزّه‌تر از همهٔ غذاها است
celow-kabāb xošmazzetar az hame-ye γazā hā ast
“Chelo-kabaab is the most delicious of all foods.”