What happens when the lead is converted? Or what is the lead conversion process?

When a Lead is converted in Salesforce, the platform runs a coordinated multi-record transaction that creates the working sales records (Account, Contact, optional Opportunity), maps Lead data into them, migrates related child data, and finally locks the Lead as a historical record. The whole process is atomic — it either fully succeeds or fully rolls back.

The full conversion sequence

Step by step, here’s what happens:

1. New Account is created (or an existing one is reused)

• If creating new: Account.Name = Lead.Company, address fields copy over, Industry / Type / Rating / etc. map across.
• If reusing: Lead fields don’t overwrite the existing Account’s data — the Account stays as is.
• Account ownership goes to the conversion user unless overridden in the dialog.

2. New Contact is created (or an existing one is reused)

• Person-level Lead fields map to Contact: FirstName, LastName, Title, Email, Phone, Mobile, MailingAddress, etc.
• The Contact is linked to the Account (Contact.AccountId).
• If reusing an existing Contact, Lead fields don’t overwrite by default.

3. New Opportunity is created (optional)

• If the user didn’t check “Don’t create an Opportunity”:
  • Opportunity Name = whatever the user typed (default suggestion is “[Company] - ”)
  • Opportunity.AccountId = the new/reused Account
  • Opportunity.CloseDate, Amount, StageName come from the conversion dialog
  • An Opportunity Contact Role row is created linking the new Contact to the Opportunity, with Is Primary = true

4. Custom field mapping is applied

• Salesforce reads the Lead Field Mapping configuration (Setup → Object Manager → Lead → Map Lead Fields).
• Each custom Lead field with a mapping has its value copied to the corresponding Account / Contact / Opportunity field.
• Unmapped custom Lead fields are lost — their values don’t survive conversion.

5. Activities are migrated

Open and closed Tasks, Events, Notes, and Emails on the Lead are reparented:

• Tasks and Events move to the new Contact (Task.WhoId = Contact Id) and the new Account/Opportunity (Task.WhatId = Opportunity or Account).
• Email logs and Notes follow similar rules.
• The activity history on the Account now shows everything that happened on the original Lead.

6. Campaign Members are migrated

• For each CampaignMember row where LeadId = the converted Lead, a corresponding row is updated/created with ContactId = the new Contact.
• The marketing-source attribution survives the conversion.

7. Files and attachments

• Notes and Attachments on the Lead are reparented per the file-sharing model — Lightning Files associated with the Lead are linked to the new records.

8. Lead is marked converted

The Lead record itself is updated:

The Lead becomes read-only for most fields and most users. Only a handful of admin-controllable system fields remain editable.

9. Triggers and automation fire

• All applicable triggers on Account, Contact, Opportunity fire as if you’d inserted/updated them manually.
• Validation rules apply — if they fail, the whole conversion rolls back.
• Workflow rules, processes, and flows fire.
• Auto-assignment rules on Account or Opportunity can fire (depending on configuration).
• Lead triggers also fire (on update, since IsConverted flipped from false to true). Critical: your Lead trigger should check Trigger.new[i].isConverted && !Trigger.old[i].isConverted to detect conversion specifically.

What does NOT happen automatically

• Account team members are not copied — only ownership.
• Opportunity team members are not copied — only ownership.
• Custom related-list relationships from Lead to other objects don’t migrate — you’d need a trigger or flow.
• Validation rules that block conversion must be coded specifically — by default Salesforce doesn’t skip them.

Common failures during conversion

Validation rules on Account / Contact / Opportunity that fire on insert can block conversion. If you require, say, Account.Industry to be set but the Lead didn’t carry that data, conversion fails with the validation error. The user must fix the Lead, then retry.

For required Opportunity fields, the conversion dialog can collect them — but only the standard fields.

Conversion settings (admin controls)

In Setup → Lead Settings:

• Require Validation for Converted Leads — toggles whether validation rules apply to the Lead at conversion
• Preserve Lead Status when converted — whether the Status from the Lead persists
• Enable Conversions for Leads with Active Assignment Rules — controls whether the assignment rule fires for the new records

Bottom line

Lead conversion is a single transaction that creates the trio of Account / Contact / Opportunity (or attaches to existing), maps configured custom fields, migrates activities and campaign members, fires all standard automation on the new records, then locks the Lead with its conversion metadata. Plan your custom field mapping carefully — anything not mapped is lost.

Verified against: Salesforce Help — How Leads Are Mapped When Converted. Last reviewed 2026-05-17.