Salesforce Duplicate Rules: Complete Setup Guide

Duplicate records are the silent killer of CRM data quality. They skew reports, confuse sales reps, and make your marketing automation unreliable.

Salesforce provides powerful native tools to prevent and manage duplicates. This guide shows you exactly how to set them up.

How Salesforce Duplicate Management Works

Salesforce duplicate management has two components:

Matching Rules: Define how records are compared (what fields, what logic)
Duplicate Rules: Define what happens when a match is found (block, alert, or allow)

New Record Created
       │
       ▼
┌─────────────────┐
│  MATCHING RULES │ ← Compare against existing records
│                 │   using defined field logic
└─────────────────┘
       │
       ▼
   Match Found?
       │
   Yes │ No
       │    └──→ Record created normally
       ▼
┌─────────────────┐
│ DUPLICATE RULES │ ← Determine action:
│                 │   Block, Alert, or Allow
└─────────────────┘
       │
       ▼
  Action Executed

Standard vs Custom Matching Rules

Standard Matching Rules

Salesforce includes pre-built matching rules:

Standard Contact Matching Rule

Matches on: Email OR (First Name + Last Name + Account)
Uses fuzzy matching on names

Standard Lead Matching Rule

Matches on: Email OR (First Name + Last Name + Company)
Uses fuzzy matching on names

Standard Account Matching Rule

Matches on: Account Name + Billing Address
Uses fuzzy matching on names

These work for basic use cases but often need customization.

Custom Matching Rules

You can create custom rules for more precise matching. Custom rules let you:

Add additional fields
Adjust match sensitivity
Use exact vs. fuzzy matching
Create cross-object matching (Lead to Contact)

Setting Up Matching Rules

Step 1: Navigate to Matching Rules

Go to Setup
Search for “Matching Rules”
Click Matching Rules

Step 2: Create a New Matching Rule

Click New Rule
Select the object (Lead, Contact, or Account)
Give it a descriptive name (e.g., “Contact - Email Exact Match”)

Step 3: Define Matching Criteria

Add matching conditions. Each condition specifies:

Field: Which field to compare
Matching Method: Exact or Fuzzy
Match Blank Fields: Whether blanks should match blanks

Example configuration for contacts:

Condition 1:
  Field: Email
  Matching Method: Exact
  Match Blank Fields: No

OR

Condition 2:
  Field: First Name
  Matching Method: Fuzzy (First Name)
  Match Blank Fields: No

AND

  Field: Last Name
  Matching Method: Fuzzy (Last Name)
  Match Blank Fields: No

AND

  Field: Account Name
  Matching Method: Fuzzy (Company Name)
  Match Blank Fields: No

Step 4: Activate the Rule

Save the matching rule
Click Activate
The rule is now available for duplicate rules

Understanding Matching Methods

Exact Matching

Exact matching requires fields to be identical (case-insensitive):

“john@acme.com” matches “JOHN@ACME.COM” ✓
“john@acme.com” matches “john@acme.co” ✗

Use exact matching for:

Email addresses
Phone numbers (after standardization)
Custom IDs

Fuzzy Matching

Fuzzy matching uses algorithms to match similar values:

“John Smith” matches “Jon Smith” ✓
“Acme Inc” matches “ACME Incorporated” ✓

Fuzzy matching types:

First Name: Optimized for first names, handles nicknames
Last Name: Optimized for last names
Company Name: Handles Inc, LLC, Corp variations
Title: Matches similar job titles
City: Handles city name variations
Street: Handles street abbreviations (St, Street, Ave)
Phone: Matches formatted vs unformatted numbers

Use fuzzy matching for:

Names
Company names
Addresses

Matching Method Comparison

Method	”John Smith” vs “Jon Smith"	"John Smith” vs “John Smyth”
Exact	No Match	No Match
Fuzzy (First Name)	Match	No Match
Fuzzy (Last Name)	N/A	Match

Setting Up Duplicate Rules

Once you have matching rules, create duplicate rules to define what happens when matches are found.

Step 1: Navigate to Duplicate Rules

Go to Setup
Search for “Duplicate Rules”
Click Duplicate Rules

Step 2: Create a New Duplicate Rule

Click New Rule
Select the object
Configure the rule settings

Step 3: Configure Rule Settings

Record-Level Security

Bypass sharing rules: Should the rule see all records, or only those the user can see?
Recommendation: Enable bypass for admins, disable for regular users

Actions

Block: Prevent the duplicate from being saved
Alert: Show warning but allow save
Report: Log duplicates without blocking or alerting

Alert Text Customize the message users see:

"A potential duplicate was found. Please review:
{!Duplicate.Name} at {!Duplicate.Account.Name}"

Step 4: Add Matching Rules

Link your matching rules to the duplicate rule:

Click Add Matching Rule
Select your matching rule
Choose which objects to compare against:
- Same object (Lead to Lead)
- Different object (Lead to Contact)

Step 5: Activate the Rule

Save the duplicate rule
Click Activate
Test with sample data

Cross-Object Duplicate Detection

One of Salesforce’s most powerful features is cross-object matching—detecting when a Lead duplicates an existing Contact.

Setting Up Lead-to-Contact Matching

Matching Rule (Create if not exists):

Object: Lead
Name: Lead to Contact - Email Match

Condition 1:
  Field: Email
  Matching Method: Exact
  Filter Logic: 1

Duplicate Rule:

Object: Lead
Name: Prevent Duplicate Leads (Contact Match)

Matching Rules:
  1. Lead to Contact - Email Match
     Compare Against: Contact

Action: Alert (or Block)

Alert Text:
"This lead may already exist as a contact:
{!Duplicate.Name} at {!Duplicate.Account.Name}"

Now when someone creates a Lead with an email that matches a Contact, they’ll be warned (or blocked).

Recommended Duplicate Rule Configurations

Configuration 1: Strict Email Matching (Recommended Starting Point)

For Leads:

Rule Name: Lead - Email Exact Match
Matching Rule: Email (Exact)
Compare Against: Lead, Contact
Action: Alert

For Contacts:

Rule Name: Contact - Email Exact Match
Matching Rule: Email (Exact)
Compare Against: Contact
Action: Alert

For Accounts:

Rule Name: Account - Name + Website Match
Matching Rule: Company Name (Fuzzy) + Website (Exact)
Compare Against: Account
Action: Alert

Configuration 2: Comprehensive Matching (Tighter Control)

For Leads:

Rule Name: Lead - Multi-Field Match
Matching Rules:
  1. Email (Exact) - Compare to Lead, Contact
  2. First Name (Fuzzy) + Last Name (Fuzzy) + Company (Fuzzy) - Compare to Lead
Action: Alert for Rule 1, Alert for Rule 2

Configuration 3: Block Mode (Strict Enforcement)

For organizations that want to prevent duplicates entirely:

Rule Name: Lead - Block Duplicates
Matching Rule: Email (Exact)
Compare Against: Lead, Contact
Action: Block

Alert Text:
"Cannot create this lead. A record with this email already exists:
{!Duplicate.Name}
Please update the existing record instead."

Handling Exceptions

Sometimes you need to allow duplicates (e.g., same person, different company). Create exception rules:

Exception by Profile

Create a separate duplicate rule with “Allow” action for specific profiles:

Rule Name: Lead - Allow Duplicates (Data Team)
Matching Rule: Email (Exact)
Action: Report (log only)
Run Rule: For profiles "Data Admin", "System Admin"

Exception by Record Type

Use record type conditions to allow duplicates for certain scenarios:

Rule Name: Contact - Alert Non-Customer
Matching Rule: Email (Exact)
Condition: Record Type != "Customer"
Action: Alert

Data Quality Before Duplicate Rules

Duplicate rules prevent new duplicates. But what about existing duplicates?

Step 1: Clean Existing Data First

Before activating strict duplicate rules:

Run duplicate reports to identify existing duplicates
Use DemandTools or Cloudingo to merge
Standardize data formatting (phones, addresses)
Then activate duplicate rules

Step 2: Standardize on Entry

Create validation rules to ensure data is formatted consistently:

Phone Number Standardization:

Rule: Phone must be 10 digits
Formula: NOT(REGEX(Phone, "^[0-9]{10}$"))
Error: "Phone number must be 10 digits, numbers only"

Email Lowercase: Use a Flow to automatically lowercase emails on save.

Step 3: Monitor Duplicate Reports

After activating rules, monitor the Duplicate Record Sets report:

Go to Reports
Find “Duplicate Record Sets”
Review flagged duplicates weekly
Merge or dismiss as appropriate

Troubleshooting Common Issues

Issue: Too Many False Positives

Symptoms: Users complain about constant duplicate warnings for non-duplicates.

Solutions:

Tighten matching criteria (add more required fields)
Switch from Fuzzy to Exact matching
Add conditions to exclude certain records

Issue: Duplicates Still Getting Through

Symptoms: Duplicates are created despite active rules.

Check:

Is the rule activated?
Does the user’s profile bypass the rule?
Is the data coming through API? (Check API settings)
Are matching fields populated?

Issue: Performance Degradation

Symptoms: Record saves are slow after enabling rules.