Google analytics showing wrong number of users

Question

I'm using Google analytics since one week on a new website. I didn't change anything. I got the code and I placed it on my website like I did with other websites before. The problem now is the dashboard shows the number of users from yesturday is 1,200. I was surprised because I had more. So what I did is I changed the graph to show the number of users per hour for yesturday only and I extracted the data into CSV. The excel file says my users is 2,100 which is right and that's what the graph shows over 24 hours (I calculated them too).

So my question is why does the dashboard shows wrong number of users? (It's not daily, but if you select weekly there's a wrong too).

Attached are the screenshot and the CSV file from yesturday.

What can I do in this situation?

Thank you!

Hour Index  Users
0   77
1   52
2   39
3   24
4   14
5   10
6   15
7   27
8   51
9   71
10  98
11  142
12  123
13  138
14  133
15  121
16  141
17  142
18  130
19  125
20  118
21  122
22  103
23  108
    2,124

Answer 1

The users per hour do not sum up to the users during the day. Each hour, Google Anaytics tells you how many users there were on the site during that hour. If Tom visited your site at 9:00am and also at 11:00am, he would count 1 one user for both the rows 9 and 11 in your spreadsheet. But, he would only count as 1 user for the day.

Works the same way for days and weeks. If you add up the users each day, it will typically be less than the users for the week. Because some users likely visited your site on more than one day.