No, 3 hours on high is not the same as 6 hours on low for a slow cooker. Slow cookers, also known as crock-pots, have different temperature settings that correspond to different cooking times.
Typically, the "high" setting on a slow cooker cooks at a higher temperature and is intended for faster cooking. The "low" setting, on the other hand, cooks at a lower temperature and is meant for slower cooking, which can result in more tender and flavorful dishes.
As a general rule of thumb, the "high" setting usually cooks food in about half the time it takes on the "low" setting. So, if a recipe calls for cooking a dish on low for 6 hours, you should expect it to take approximately 3 hours if cooked on high. Similarly, if a recipe calls for cooking on high for 3 hours, it would take roughly 6 hours on low.
However, it's essential to note that every slow cooker is different, and cooking times can vary depending on the size of the slow cooker and the specific dish you are preparing. To ensure your food is properly cooked and safe to eat, always follow the specific cooking time and temperature guidelines provided in your recipe. If you're unsure, it's best to consult your slow cooker's manual or the recipe's instructions for accurate cooking times and settings.