When comparing two or more people, things, places, etc., you can express that they are the same by using the expressions so ... wie ..., genauso ... wie..., or nicht so ... wie ... and the basic forms of adjectives.
Die Hexe ist genauso böse wie die Königin.
The witch is just as evil as the queen.
Und sogar der Frosch ist nicht so hässlich wie sie!
And even the frog is not as ugly as she is!
Und sie ist so alt wie ein Stein!
And she is as old as the rocks!
Differences between two entities
When comparing two people, things, places, etc., you can say that one is bigger ..., smaller ..., more ..., less ... than the other with the comparative forms of the adjectives (for regular adjectives the ending is -er) and expressions such as als ... or immer ...
Thilo ist viel niedlicher als der Froschkönig.
Thilo is much cuter than the frog prince.
Gerdi wird immer gieriger!
Gerdi is getting more and more greedy!
Differences among three or more entities
When comparing more than two people, things, places, etc., you can express that something is the best, the hippest, the bee's knees by using the superlative forms of adjectives (for regular adjectives, the ending is -est) and expressions such as in der ganzen Welt (in the whole world) or unter allen anderen ... (among all others)
Die Königin will wissen, wer die schönste Frau im Lande ist.
The queen wants to know who the most beautiful woman in the country is.
Die Königin sollte mehr lesen! JEDER weiß, dass Schneewittchen am schönsten ist.
The queen should read more! EVERYONE knows that Snow White is most beautiful (of all).
Regular adjectives
Regular comparative and superlative adjectives merely put an -er and an -est ending on the basic adjective, even if they are very long (in contrast to English, which uses 'more' or 'most' if the adjective is more than two syllables long, such as diligent or intelligent). In the column 'superlative' the first version (e.g., 'die böste') is the attributive adjective, while the second version (e.g., 'am bösesten) is the predicate adjective. Remember: 'the most evil queen' is an attributive adjective and 'this queen was the most evil' is a predicate adjective.
basic
comparative
superlative
english
böse
böser
die böseste/am bösesten
evil/more evil/most evil
faul
fauler
die faulste/am faulsten
lazy/lazier/laziest
fleißig
fleißiger
die fleißigste/am fleißigsten
diligent/more diligent/most diligent
klein
kleiner
die kleinste/am kleinsten
small/smaller/smallest
traurig
trauriger
die traurigste/am traurigsten
sad/sadder/saddest
Irregular adjectives
Irregular comparative and superlative adjectives put an -er and an -est ending on the basic adjective, in addition to changes to the word stem. For example, syllables that are one syllable long and have -a-, -o-, -u-.
basic
comparative
superlative
english
alt
älter
die älteste/am ältesten
old/older/oldest
arm
ärmer
die ärmste/am ärmsten
poor/poorer/poorest
dumm
dümmer
die dümmste/am dümmsten
dumb/dumber/dumbest
jung
jünger
die jüngste/am jüngsten
young/younger/youngest
kalt
kälter
die kälteste/am kältesten
cold/colder/coldest
klug
klüger
die klügste/am klügsten
smart/smarter/smartest
lang
länger
die längste/am längsten
long/longer/longest
scharf
schärfer
die schärfste/am schärfsten
sharp/sharper/sharpest
schwach
schwächer
die schwächste/am schwächsten
weak/weaker/weakest
stark
stärker
die stärkste/am stärksten
strong/stronger/strongest
warm
wärmer
die wärmste/am wärmsten
warm/warmer/warmest
Adjectives that end in -el, -en or -er drop the -e- before the comparative endings (but keep it in the superlative form!):
basic
comparative
superlative
english
bitter
bittrer
die bitterste/am bittersten
bitter/more bitter/most bitter
dunkel
dunkler
die dunkelste/am dunkelsten
dark/darker/darkest
teuer
teurer
die teuerste/am teuersten
expensive/more expensive/most expensive
Adjectives that end in -s, -ß, -z, -d, -t or a vowel ... add an -e before the superlative -st suffix or drop the -s from the -st (adding the Umlaut in the one-syllable -a, -o, -u adjectives):
basic
comparative
superlative
english
boshaft
boshafter
die boshafteste/am boshaftesten
malicious/more malicious/most malicious
groß
größer
die größte/am größten
big/bigger/biggest
hart
härter
die härteste/am härtesten
hard/harder/hardest
intelligent
intelligenter
die intelligenteste/am intelligentesten
intelligent/more intelligent/most intelligent
nett
netter
die netteste/am nettesten
nice/nicer/nicest
schlau
schlauer
die schlaueste/am schlauesten
smart/smarter/smartest
schwarz
schwärzer
die schwärzeste/am schwärzesten
black/blacker/blackest
süß
süßer
die süßeste/am süßesten
sweet/sweeter/sweetest
And of course, some adjectives are utterly irregular! You simply need to memorize these:
basic
comparative
superlative
english
gut
besser
die beste/am besten
good/better/best
hoch
höher
die höchste/am höchsten
tall(high)/taller/tallest
nah
näher
die nächste/am nächsten
near/nearer/nearest
viel
mehr
die meiste/am meisten
many/more/most
Adjective endings
Attributive adjectives
Attributive adjectives (in contrast with predicate adjectives) are placed before the noun and take endings in both the basic and comparative/superlative forms depending on the gender, number and case of the noun they describe.
Comparative or superlative adjectives that precede nouns take the same adjective endings as basic (i.e., non-comparative/superlative) attributive adjectives, in addition to the comparative and superlative endings. They can be preceded by der-words, by ein-words or by other determiners.
Schneewittchen arbeitet auf einen höheren Lebensstandard für Märchenfiguren hin.
Snow White is working for a higher standard of living for fairy tale characters.
Aschenputtels Vater würde seinen Stieftöchtern nicht mehr die teuersten Geschenke vom Markt kaufen.
Cinderella's father would no longer buy his stepdaughters the most expensive gifts from the market.
Predicate adjectives: comparative
Comparative adjectives that follow nouns (separated by a verb such as sein, werden, heißen) take only the comparative endings, but no other adjective endings.
Wolfgang ist viel moderner als Wolfdietrich.
Wolfgang ismuch more modern than Wolfdietrich.
Tja, er ist auch viel hochnäsiger!
Yes, well, he is also much snootier!
Predicate adjectives: superlative
Superlative adjectives that follow nouns take another kind of superlative ending -sten and are preceded by am.
Welches Märchen ist am interessantesten?
Which fairy tale is the most interesting?
Das weiß ich nicht, aber ohne Frage ist Aschenputtel am rachsüchtigsten! Weißt du, was mit den Stiefschwestern geschehen ist?!?
That I don't know, but without question Cinderella is the most vengeful! Do you know what happened to the stepsisters?!?