Vulkan and swapchain image count

A silly question about Vulkan swapchains.

In the structure VkSurfaceCapabilitiesKHR there is a minImageCount member. I understand that the swapchain needs at least minImageCount images. That said, I'm a bit confused at what this number means. What I mean is...

On my system (Windows 7, NVidia 970) the minimum image count is 2. So say I wanted to use double buffering, would I create a swapchain with 2 images or 3? Is that 2 minImageCount images 2 that the OS needs for internal purposes and I have to request any extra I need, or is that 2 just straight up 2 swapchain images that I can use. Likewise if I want to use triple buffering (for examle VK_PRESENT_MODE_MAILBOX_KHR) would I create a swapchain with 3 or 4 images?