Q: do my apple ipad and iphone have built in voltage converters for European travel?

A voltage converter is not needed. All Apple products will operate automatically on 100-240 Volts and 50/60 Hz, so they will work correctly and automatically just about anywhere in the world as long as you have the correct type of wall AC adapter for the country to which you are traveling.

The Apple World Travel Adapter Kit you just looked at will work.

Or, you can spend about $25 less and just buy a European plug adapter.

That's all you need.

While generally true, the answers above are not quite accurate.

Technically, the iPad and iPhone operate on the standard USB voltages, which are the same anywhere in the world. The plug adapter you use (that comes with the device) converts the local power voltage (typically 120V or 240V) to the USB power spec.

The power adapter itself can adapt to almost any voltage, from 100 through 250V, as denoted by the label on the device itself.

So, yes, the device will work just about anywhere in the world, but it's the power adapter that performs that magic, not the iPhone/iPad itself

As long as you can plug in the adapter, you're good to go.