Make outbound sales calls from Google Sheets using a Retell AI voice agent

This n8n workflow automates outbound phone calls to new leads using Retell AI, with built-in timezone detection to ensure you're only calling during business hours.

Use cases include appointment setting, lead qualification, follow-up surveys, payment reminders, and sales outreach—anywhere you need to scale phone conversations without scaling headcount.

Good to know

• You'll need a Retell AI phone number and configured voice agent before using this workflow.
• Retell AI offers $10 free credit when you sign up (~73 minutes of calls). Create your account here.
• The timezone logic covers common country codes (UK, US, EU, Australia, India, UAE, Singapore, Japan). You can extend this in the Code node.

How it works

• A new row in Google Sheets triggers the workflow (you can swap this for a webhook, form, or CRM trigger).
• The phone number is sanitised—stripping spaces, dashes, and brackets so it's in the correct format for dialling.
• The lead's timezone is determined from their country code, and the workflow checks whether it's between 8am-5pm local time. If not, it waits and retries.
• Retell AI places the outbound call using your configured voice agent.
• The workflow polls Retell's API until the call ends, then retrieves the transcript. You can replace this with a Retell webhook if you'd rather.
• The Google Sheet is updated to mark the lead as "Called", as well as entering the call summary, transcript, call sentiment, and other useful details from Retell's call logs.

Requirements

• Retell AI account with a phone number and voice agent
• Google Sheets with columns: Phone Number, Name, Status

Customising this workflow

• Change the trigger: Replace Google Sheets with a webhook, n8n form, or CRM trigger (HubSpot, Pipedrive, etc.)
• Adjust calling hours: Modify the IF node to change the 8am-5pm window
• Expand timezone coverage: Add more country codes to the mapping in the "Get lead's timezone" Code node
• Add your own AI analysis: We currently use Retell AI's default call summary - but you could add an agent that extracts different insights (e.g., buying signals, objections)
• Route the output elsewhere: Send results to Slack, a CRM, email, or Airtable instead of updating Google Sheets

Built by Marcus Taylor (@intellagents / voiceai.guide)