How to Clean Up Vendor List: Complete Step-by-Step Guide

If your vendor list has duplicate entries, inconsistent vendor codes, missing contact information, or mixed formatting—you're not alone. 78% of companies struggle with messy vendor data that breaks ERP imports and causes procurement delays.

By the end of this guide, your vendor list will be fully cleaned, standardized, and ready for ERP upload.

Quick Summary

Detect and remove duplicate vendors across multiple columns
Standardize vendor codes and naming conventions
Validate contact information and tax IDs
Normalize addresses and company names
Export clean vendor master ready for ERP systems

Common Problems in Vendor Lists

Duplicate vendor entries with slight variations (e.g., "Acme Corp" vs "Acme Corporation")
Inconsistent vendor codes (V-001, V001, V_001, vendor_001)
Mixed company name formats (LLC, Inc., Ltd. inconsistencies)
Invalid or missing tax IDs (EIN, VAT numbers)
Incomplete contact information (missing emails, phone numbers)
Non-standardized addresses (St. vs Street, different formats)
Merged cells breaking data structure
Mixed currencies in payment terms
Outdated vendor status (active vs inactive not marked)
Broken relationships between vendor codes and names

Step-by-Step Fix: Clean Up Vendor List

Step 1: Detect Duplicate Vendors

Duplicate vendors are the #1 problem in vendor lists. They cause payment errors, duplicate orders, and reporting chaos.

Wrong Examples:

Vendor Name          | Vendor Code
Acme Corporation     | V-001
Acme Corp            | V-001
ACME CORPORATION     | V-001
Acme Corporation LLC | V-001

Right Example:

Vendor Name          | Vendor Code
Acme Corporation LLC | V-001

Excel Formula Method:

Find duplicates by vendor code:

=COUNTIF($B$2:$B$1000, B2)>1

This formula returns TRUE for duplicate vendor codes.

Find duplicates by name (fuzzy match):

=IF(COUNTIF($A$2:$A$1000, "*"&LEFT(A2,5)&"*")>1, "Possible Duplicate", "Unique")

Remove duplicates:

Select your data range
Go to Data > Remove Duplicates
Check columns: Vendor Code, Vendor Name, Tax ID
Click OK

Python Script (Optional):

import pandas as pd
from fuzzywuzzy import fuzz

# Load vendor list
df = pd.read_excel('vendor_list.xlsx')

# Remove exact duplicates
df = df.drop_duplicates(subset=['Vendor Code'], keep='first')

# Find fuzzy duplicates by name
duplicates = []
for i, row1 in df.iterrows():
    for j, row2 in df.iterrows():
        if i < j:
            similarity = fuzz.ratio(row1['Vendor Name'], row2['Vendor Name'])
            if similarity > 85:  # 85% similarity threshold
                duplicates.append((i, j, similarity))

# Review and merge duplicates
print("Potential duplicates found:", len(duplicates))

RowTidy Usage:

Upload your vendor list to RowTidy. The AI automatically:

Detects duplicate vendors by code, name, and tax ID
Groups similar vendor names (fuzzy matching)
Suggests which entries to keep or merge
Removes duplicates with one click

Time saved: 2 hours → 2 minutes

Step 2: Standardize Vendor Codes

Vendor codes must follow a consistent format for ERP systems to work properly.

Wrong Examples:

V-001
V001
V_001
vendor_001
VENDOR-001

Right Example:

V-001
V-002
V-003

Excel Formula:

Standardize to V-XXX format:

="V-"&TEXT(VALUE(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(A2,"V-",""),"V_",""),"vendor_","")),"000")

Remove spaces and special characters:

=SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(A2," ",""),"_","-"),"vendor","V")

Power Query Method:

Select your vendor code column
Go to Data > From Table/Range
Transform column:
- Replace "V_" with "V-"
- Replace "vendor_" with "V-"
- Remove spaces
Apply changes

RowTidy Usage:

RowTidy's schema mapping automatically standardizes vendor codes:

Detects current format pattern
Applies consistent format (V-XXX, VENDOR-XXX, etc.)
Validates uniqueness
Fixes all codes in one pass

Step 3: Normalize Company Names

Company names need consistent legal entity suffixes (LLC, Inc., Corp, Ltd.).

Wrong Examples:

Acme Corp
Acme Corporation
Acme Corp.
ACME CORP
acme corp

Right Example:

Acme Corporation

Excel Formula:

Standardize case and remove extra periods:

=PROPER(SUBSTITUTE(SUBSTITUTE(A2,".",""),"  "," "))

Normalize legal suffixes:

=SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(A2,"Corp.","Corporation"),"Inc.","Incorporated"),"LLC.","LLC"),"Ltd.","Limited")

RowTidy Usage:

RowTidy's text normalization:

Converts to proper case
Standardizes legal entity suffixes
Removes extra spaces and punctuation
Handles international formats (GmbH, S.A., etc.)

Step 4: Validate Tax IDs and Contact Information

Invalid tax IDs and missing contacts break vendor onboarding in ERP systems.

Validation Rules:

EIN (US) Format: XX-XXXXXXX (9 digits with hyphen)
VAT (EU) Format: Varies by country
Email Format: Must contain @ and valid domain
Phone Format: Standardize to (XXX) XXX-XXXX

Excel Formulas:

Validate EIN format:

=IF(LEN(SUBSTITUTE(A2,"-",""))=9, "Valid", "Invalid")

Validate email:

=IF(AND(ISNUMBER(SEARCH("@",A2)), ISNUMBER(SEARCH(".",A2))), "Valid", "Invalid")

Extract and format phone:

="("&LEFT(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(A2,"(",""),")",""),"-",""),3)&") "&MID(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(A2,"(",""),")",""),"-",""),4,3)&"-"&RIGHT(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(A2,"(",""),")",""),"-",""),4)

RowTidy Usage:

RowTidy validates:

Tax ID formats by country
Email addresses (checks domain validity)
Phone numbers (standardizes format)
Flags missing required fields
Generates validation report

Step 5: Normalize Addresses

Standardized addresses are critical for shipping, invoicing, and compliance.

Wrong Examples:

123 Main St
123 Main Street
123 Main St.
123 MAIN STREET

Right Example:

123 Main Street

Excel Formula:

Standardize street suffixes:

=SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(A2,"St.","Street"),"Ave.","Avenue"),"Rd.","Road"),"Blvd.","Boulevard"),"Dr.","Drive")

Power Query Method:

Create a lookup table for address standardization:

St. → Street
Ave. → Avenue
Rd. → Road
etc.

Apply transformation using merge queries.

RowTidy Usage:

RowTidy normalizes addresses:

Standardizes street suffixes
Validates ZIP/postal codes
Formats city, state, country consistently
Geocodes for validation (optional)

Step 6: Mark Active vs Inactive Vendors

Separate active vendors from inactive ones to avoid ordering from closed suppliers.

Excel Formula:

Flag inactive vendors:

=IF(OR(B2="Closed", B2="Inactive", B2="Terminated"), "Inactive", "Active")

Filter by status:

Add filter to Status column
Select "Active" only
Copy to new sheet for clean active vendor list

RowTidy Usage:

RowTidy can:

Detect inactive vendors by keywords (Closed, Terminated, Inactive)
Create separate sheets for active/inactive
Add status column automatically

Step 7: Export Clean Vendor Master

Export your cleaned vendor list in the format your ERP system requires.

Export Formats:

Excel (.xlsx) - For manual review
CSV - For ERP import
JSON - For API integration
XML - For SAP/Oracle imports

Required Columns for ERP:

Vendor Code (unique identifier)
Vendor Name (legal name)
Tax ID (EIN/VAT)
Address (street, city, state, ZIP, country)
Contact (email, phone)
Payment Terms
Currency
Status (Active/Inactive)

RowTidy Export:

RowTidy exports vendor masters in all major ERP formats:

SAP vendor master format
Oracle vendor format
NetSuite vendor import
Custom CSV templates

Real Example: Messy Vendor List → Clean Master

Before (Messy Input):

Vendor Name	Vendor Code	Tax ID	Email	Phone	Address	Status
Acme Corp	V-001	12-3456789	john@acme.com	5551234	123 Main St	Active
Acme Corporation	V-001	12-3456789	john@acme.com	(555) 123-4567	123 Main Street	Active
ACME CORP	V_001	123456789	-	555-123-4567	123 Main St.	-
Beta LLC	V002	98-7654321	contact@beta	5559876	456 Oak Ave	Active
Beta Limited	V-002	987654321	contact@beta.com	(555) 987-6543	456 Oak Avenue	Closed

After (Clean Output):

Vendor Code	Vendor Name	Tax ID	Email	Phone	Address	Status
V-001	Acme Corporation	12-3456789	john@acme.com	(555) 123-4567	123 Main Street	Active
V-002	Beta Limited	98-7654321	contact@beta.com	(555) 987-6543	456 Oak Avenue	Inactive

Changes Made:

Removed 3 duplicate entries for Acme
Standardized vendor codes (V-001, V-002)
Normalized company names (Corporation, Limited)
Validated and formatted tax IDs
Fixed email addresses
Standardized phone format
Normalized addresses (Street, Avenue)
Marked inactive vendors

Mini Automation Using RowTidy

You can clean your entire vendor list in 10 seconds using RowTidy's AI Recipes.

How it works:

Upload your messy vendor list Excel file
RowTidy detects vendor code patterns, duplicate entries, and formatting issues
AI suggests cleaning rules (standardize codes, remove duplicates, normalize names)
Apply cleaning with one click
Export clean vendor master ready for ERP import

RowTidy Recipe for Vendor Lists:

Auto-detect vendor code format
Remove duplicates by code, name, and tax ID
Standardize company names and legal suffixes
Validate tax IDs, emails, and phone numbers
Normalize addresses
Mark active/inactive status
Export in ERP format

Time saved: 4-6 hours of manual work → 30 seconds

Instead of doing this manually every month, let AI do it for you. Try RowTidy's vendor cleaning recipe →

FAQ

1. How often should I clean up my vendor list?

Clean your vendor list quarterly, or whenever you receive vendor updates from suppliers. Monthly cleaning is recommended for companies with 100+ vendors.

2. What's the best way to prevent duplicate vendors?

Use a standardized vendor code format and validate uniqueness before adding new vendors. RowTidy's duplicate detection prevents duplicates automatically.

3. Can I merge vendor history when removing duplicates?

Yes, but be careful. When merging duplicate vendors, ensure you preserve purchase history, payment terms, and contracts. Export a backup before merging.

4. What vendor data is required for ERP import?

Minimum required: Vendor Code (unique), Vendor Name, Tax ID, Address, Contact Email. Optional: Phone, Payment Terms, Currency, Bank Details.

5. How do I handle vendors with multiple locations?

Create separate vendor codes for each location (e.g., V-001-HQ, V-001-WH) or use a vendor-location hierarchy in your ERP system.

6. What if my vendor list has 10,000+ entries?

Use automated tools like RowTidy or Power Query. Manual cleaning of large vendor lists is error-prone and time-consuming.

7. How do I validate international tax IDs (VAT, GST)?

Use country-specific validation rules. RowTidy supports VAT validation for EU countries, GST for India, and other international formats.

8. Can I clean vendor lists from multiple sources?

Yes. RowTidy can merge vendor lists from Excel, CSV, Google Sheets, and databases, then deduplicate and standardize them into one master list.

9. What's the difference between vendor code and vendor name?

Vendor code is a unique identifier (e.g., V-001) used by your system. Vendor name is the legal company name (e.g., Acme Corporation LLC). Both must be consistent.

10. How do I handle vendor name changes (mergers, acquisitions)?

Update the vendor name but keep the same vendor code to preserve history. Add a note in the vendor master about the name change date.

Related Guides

Conclusion

Cleaning up your vendor list is essential for smooth procurement, accurate reporting, and ERP integration. By following these steps—detecting duplicates, standardizing codes, validating data, and normalizing formats—you'll have a clean vendor master ready for import.

Try RowTidy — the fastest way to clean messy vendor lists and prepare them for ERP upload.