Bulk upload of accounts into existing QB online company

It's good to have you here in the Community, Katie.

Yes, you can upload your 100 new accounts using a spreadsheet in Excel, Google Sheets, or a CSV file without affecting your current Chart of Accounts. Allow me to walk you through how to do it.

First, we need to format your spreadsheet correctly. Here's how:

1. Open your spreadsheets to add your 100 new accounts and ensure to have these columns:
   -  Account Number
   -  Account Name
   -  Type
   -  Detail Type
2.  If you have a sub-account, add it in the Account Name column in this format: Main account: sub-account. For example, Utilities: Gas. See the table below for more examples of how to format sub-accounts.
3. If you're satisfied, save your spreadsheet either in Google Sheets, Excel, or CSV format wherever you created it.

You can check the image below for reference:

Feel free to read this article for more details: Import your chart of accounts to QuickBooks Online.

Once done, you can then proceed on uploading your file into QuickBooks Online by routing to:
 

1. Gear icon.
2. Below on the Tools section, select Import Data. 
3. Choose the Chart of Accounts.
4. Afterward, you'll be routed to Import accounts, for CSV or Excel files.
5. Click Browse and if it's Google Sheets, then click Connect. 
6. Next, Map Data where your file uploaded will be compared to the QBO field for accuracy
7. Click the Next icon to review your account, then click Import.

If you see duplicate accounts and you want to make them one, you can read through this article: Merge duplicate accounts, customers, suppliers, and employees in QuickBooks Online.

Click the Reply button below if you have more questions about managing your Chart or accounts in QuickBooks Online. I'll be more than happy to lend a hand. Take care and have a wonderful day!

@KatieDeering 

You can import the new COA in bulk and use a backup restore app to lower any risks.

https://partnerwithus.rewind.com/quickbooks