Quoting averynkh
may i kow which one is more centre area?
They are about 100 metres apart. Here's a link to a Google map which shows both on the same map.
I then did a search here on Travellerspoint and here's a list of properties available on 1 August (didn't have your dates, so just used this) with their ratings, price per person, per night and distance from half way in between the rail and bus stations
I stopped the list at properties further than 1 km away.
Hotel Ansgar
0.07km (Hotel)
77%
From €44
Absalon Annex
0.17km (Hostel)
74%
From €37
Hotel Nebo Copenhagen
0.18km (Hotel)
78%
From €33
Hotel Selandia
0.19km (Hotel)
76%
From €49
Hotel Loeven
0.36km (Hotel)
79%
From €34
City Public Hostel
0.45km (Hostel)
67%
From €18
Hotel Copenhagen
0.69km (Hotel)
70%
From €28
Hotel Euroglobe
0.82km (Hotel)
59%
From €32
CABINN Copenhagen Express
0.89km (Hotel)
71%
From €38
Hotel Jorgensen
0.96km (Hostel)
30%
From €23
If you want to do a similar search for the correct dates, visit the Copenhagen budget accommodation page and fill in the form at the top with dates and preferred currency. Hit the 'check availability and prices' button which will give you a list of all properties available on those dates. To see the distance from where you're arriving, just filter by 'Distance' instead of 'Popularity' and enlarge the map that's showing at the top of the page. You'll see a big reddish marker in the middle which you can drag around and it will automatically show you the list of available properties and their distance from the marker. If you then zoom in and stick the marker right on top of the bus station or train station, you'll have a really accurate idea of where each hostel is located compared to where you're arriving! Sounds complicated, but it's not that bad 