---
title: ToolRouter — Agent Use Case Guide
description: Step-by-step guide for completing a task with a specific AI agent using ToolRouter.
url: https://toolrouter.com/tools/timezone-converter/use-cases/calculate-business-hours-overlap/chatgpt
---
# How to Calculate Business Hours Overlap with ChatGPT

ChatGPT makes global time coordination feel effortless by understanding the human context behind every timezone conversion. It ranks meeting time options by fairness across participants, writes ready-to-use timezone tables for event invitations, and helps you think through the practical implications of time differences -- like whether your Asia-Pacific colleagues will be joining a 6 AM call or a reasonable mid-morning one. ChatGPT also plans around DST changes and suggests rotating schedules to share inconvenience fairly.

## Setup

{"mcpServers":{"toolrouter":{"command":"npx","args":["-y","toolrouter-mcp"]}}}

## Steps

1. Configure ToolRouter in ChatGPT
2. Ask: "Find the overlapping business hours between these two offices"
3. ChatGPT calculates the shared window
4. Request: "How does this change during daylight saving time?"

## Example Prompt

```
Our teams are in San Francisco (9-5 PST) and Berlin (9-5 CET). When can they both collaborate in real time?
```

## Tips

- ChatGPT can visualize the overlap on a timeline
- Ask about the worst-case overlap during DST transitions
