How to Import Data into an Existing Notion Database

11 Dec, 2025

Author

Antonina Smyrnova

4 min read

notion

sync

two-way sync

database

Most teams will need to import data into Notion at some point, especially when switching from spreadsheets, CRMs, project management tools, or other systems. Notion is flexible, but importing data can be challenging. People often find that Notion creates new databases, duplicates rows, mismatches fields, or breaks the database structure when handling large files.

This guide will show you the safest and easiest ways to import data into an existing Notion database without running into issues. It also explains how to automate the process with resynced.io, a tool that syncs Notion with Google Sheets, monday.com, and other systems.

If you are cleaning up a CRM, adding many project tasks, or moving a content calendar, this step-by-step guide will help you do it correctly the first time.

Understanding How Notion Imports Work

When you try to import data into an existing Notion database, you might be surprised that Notion handles imports differently based on several factors:

file type
structure
existing column names
whether the database already contains data

This can lead to unexpected behaviors, such as:

Notion creating a new database instead of updating the old one
New properties appearing automatically
Rows being duplicated because Notion cannot match them
Issues when columns use inconsistent formats (dates, multi-select, etc.)

Knowing these limitations is the first step to making your import go smoothly.

Preparing Your Data Before You Import into an Existing Notion Database

Clean data can save you hours of trouble. Before you import, always check the following:

Column names

Make sure the names match exactly with those in Notion. “Email Address” ≠ “email_address” ≠ “Email”

Date formats

Use ISO-friendly formats like 2025-05-12, or clear formats such as Jan 12, 2025.

Multi-select options

If you use multi-select, make sure the values match what is already in Notion.

No blank rows

Blank rows can often cause unexpected results during import.

Unique identifiers

This is the most important part of a clean import. Use a column like:

Email
Record ID
SKU
URL slug
Task ID

This prevents duplicates and helps Notion or your import tool match items correctly.

How to Identify Duplicate Rows Before Importing

Notion does not detect duplicates automatically. To avoid issues:

1. Use the “Remove duplicates” feature in Google Sheets or Excel

This is the fastest way to clean your data.

2. Sort by your unique identifier

This quickly shows any accidental duplicates.

3. Normalize formatting

For example:

“john.smith@gmail.com” vs “JOHN.SMITH@GMAIL.COM”
“Marketing” vs “marketing” vs “ MARKETING ”

4. Look for near-duplicates

Two rows might differ by just one character, which can make Notion treat them as new entries.

Once your data is clean, you are ready to import it into your existing Notion database without any problems.

How to Import Data into an Existing Notion Database

Importing data into an existing Notion database is much easier when you know what Notion expects and how it reads your file. Below are detailed instructions, practical examples, and common mistakes to help you avoid problems.

Option 1. Import Using Notion’s CSV Import Tool

Using CSV import is the most reliable way to add large amounts of structured data to an existing Notion database.

Step 1. Open the Database

Navigate to the Notion database where you want the data to land. Go to the Notion database where you want to add the data.

Step 2. Click the “…” Menu

In the top-right corner, click the three-dot menu and select "Merge with CSV."

This tells Notion you want to add rows to this database rather than create a new one.

Step 3. Upload the CSV File

Choose the CSV file you prepared. Be sure that:

Column names match exactly
Data formats are clean
No hidden characters remain from a previous export
The file uses UTF-8 encoding (prevents weird characters)

Step 4. Map Columns Carefully

This step is the most important.

Notion will try to match columns automatically, but you should double-check the following:

Those dates import as dates
That multi-select values match existing tags
That emails, numbers, and text fields align correctly
That no new unnecessary properties appear

Step 5. Confirm the Import

After you approve the mapping, Notion will add the CSV data to your existing database.

Option 2. Copy and Paste for Small Imports

Copy and paste is a good shortcut when:

You are working with 100 to 200 rows
Your data is well structured
You do not need detailed field mapping

How it works:

Select the whole table in Google Sheets or Excel
Paste it into Notion below your current rows

Notion will prompt you to map columns. After that, it will add the new rows.

datasets > 500 rows
complex multi-select or relation properties
anything requiring precise mapping
recurring imports
Copying and pasting works well for quick fixes, but not for long-term workflows.

Option 3. Automated Imports and Continuous Syncing

Manual imports are good for one-time tasks. Automation keeps things updated all the time.

Tools like resynced.io allow you to:

Instead of uploading CSV files weekly or monthly, your Notion database will stay up to date every few minutes.

For more information on how to synchronize two Notion databases, you can check out the detailed video.

Conclusion

Knowing how to import data into an existing Notion database is important for anyone managing real-world data. With good preparation, clean formatting, and a consistent structure, manual imports can work well for one-time tasks.

But for ongoing updates, especially when using tools like Google Sheets or Monday.com, resynced.io is the fastest, cleanest, and most reliable way to keep your data organized without manual work.

So if you deal with cleaning up a CRM, managing project pipelines, or building a company-wide knowledge system, using the right method will help your Notion database stay accurate, organized, and ready for the future.

Ready to try? Sign up for free and experiment with different types of integrations.

FAQs

1. Can I import into an existing Notion database without duplicating rows?

Yes, as long as your data includes a unique identifier, such as an email or record ID. Tools like resynced.io can also match and update rows automatically to prevent duplicates.

2. Why does Notion create a new database during import?

This happens when your CSV structure does not match the existing database. Even small differences in column names or formats can make Notion create a new table instead of merging.