Going by grammar rules, there is only one way to use this word, and that is nowadays – a single word and not as three different entities like now a days. If you use the word as a phrase ‘now a days’ instead of a single word ‘nowadays’, you will only make it grammatically incorrect.
We use nowadays to refer to the present time, to define “at current times” or to indicate something that is going on in recent days:
Nowadays, Emma doesn’t feel like going out with friends. √
Now a days, Emma doesn’t feel like going out with friends. ✗
How come we don’t see Emily around nowadays. √
How come we don’t see Emily around now a days. ✗
Earlier, the adverb nowadays used to be a three-word phrase, however, since 1880, grammarians have cut it short into a single word. Hence, the single word nowadays is the favoured choice in Modern English.
Some example sentences of ‘nowadays’
Less and less people go to cinema nowadays.
People don’t carry their umbrellas much nowadays.
Young people nowadays don’t walk in the morning any more.
She doesn’t watch TV very much nowadays. She says there’s biased reporting.
The kitchens of nowadays are much more efficient than they had ever been.
People’s perspective on marriage is quite different nowadays than it was even a few years ago.
Nowadays you don’t see a young person vacate their seat for an older person on the bus.
TV shows nowadays don’t seem to last more than a couple of months, then you never hear of them again.
Alternatively, you can also use ‘these days’ or ‘today’ as adverbs meaning ‘at the present time, in comparison with the past’. ‘These days’ is more informal while ‘today’ is slightly formal.
Be careful! Do not use nowadays or these days with the possessive’s construction before a noun, or with of after a noun. With today, the possessive is quite normal: ‘today’s society’, ‘in today’s age’, ‘today’s world’, ‘today’s economic climate’, ‘today’s standards’:
Today’s world, and the world of the future, is different. √
Nowadays’ world, and the world of the future, is different. ✗
These days’ world, and the world of the future, is different. ✗
Also, do not use ‘nowadays’, ‘these days’ or ‘today’ as adjectives:
Computers nowadays/these days/today are much more efficient and economical. √
The nowadays computers /The these days computers/ The today’s computers are much more efficient and economical. ✗
More example sentences of ‘nowadays’
Nowadays many people condemn cruelty to animals.
Many employers nowadays give their employees bonuses in the form of share options.
The only thing that’s changed is the media coverage and the public perception of politics nowadays.
There are a lot of short tricks to these problems nowadays that might not have been available in the past.
Notice that the hyphenated now-a-days has also fallen out of use.
‘Nowadays’ is the correct use, ‘now a days’ isn’t.