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)