How do I transfer books from calibre to ipad?

You need to log in the same kindle account and the purchased books will be synced automatically. If this doesn't work, you can convert the kindle books to epub file and transfer to ipad. You need to connect your Kindle device to computer and then convert the books in Kindle. After that, you can transfer the books to ipad with iTunes or iTransfer. For more details, check: A Simple Guide to Help You Read Kindle Books on iPad

What kind of new tablet do you use? If it's an iPad, you are able to download books to iPad directly. Just launch iTunes on your tablet and go to iTunes Store, then search for the book you need and click Get below the book cover.
When you want to download ebooks to iPad, you are able to sync the books with iTunes. Having the latest version of iTunes installed on computer, you are able to connect your iPad to computer with USB and sync ebooks to computer.

After getting the ebooks in iTunes library, you are able to sync the books to iPad easily. The following guidance will show you how to finish the task.
1. Plug iPad into computer via USB, and iTunes will launch automatically.
2. Click the iPad icon and choose Books category in the left sidebar.
3. Check Sync Books and choose All Books or Selected Books.
4. Click Sync at the right bottom to start syncing books to iPad.

After syncing books to iPad with iTunes, you will get the books in the iBooks app on iPad. Now you have an enjoyment. But note that you should shut down auto sync before you sync books with iTunes. To shut down auto sync of iTunes, you need to go to Edit > Preferences > Devices on iPad, and check "Prevent iPods, iPhones and iPads from syncing automatically".

If you have downloaded or got books from elsewhere, you can add books to iTunes at first, and then sync these ebooks to iPad. To add ebooks from computer to iTunes library, you only need to click File > Add File to Library at the upper left corner of iTunes, and then the ebooks will be added to iTunes Book Library.

Visit this guide for more methods about how to transfer books to iPad tablet. http://www.leawo.org/tutorial/download-ebooks-to-ipad.html

You are able to move the books to computer, and then sync ebooks to iPad with iTunes. When the Kindle users connect their Kindle tablets to computer with the USB cable, their computers will recognize their Kindle tablets as external hard drives. Then the users can copy and paste the ebooks from Kindle to computer easily. After that, the users are able to sync the books from computer to iPad with iTunes.

This is easy to be done. But when users begin to sync their iPad with iTunes, they may come up with the sync problems of iTunes. The problem may come up when users sync ebooks from iTunes to iPad. During the sync, iTunes will erase all the non-purchased items in your iPad mini. If you are new to iOS devices, you will probably lose files during the sync with iTunes, so you'd better close the auto sync and manually sync the ebooks to your iPad mini with iTunes. The following tutorial will be helpful if you aren't sure about how to accomplish the task:

1. Start iTunes and go to "Edit > Preference > Devices", and check "Prevent iPods, iPhones and iPads from syncing automatically".
2. Plug iPad into computer via USB cable, and the software will recognize your iPad and display the iPad icon at the upper right corner.
3. Click the iPad icon and choose "Books" in the summary panel. Choose the books you want to sync to iPad in the list below, and click "Apply" to start.

How to Transfer Ebooks from Kindle to iPad mini

first you need to download the Kindle App from the App-store



How to Manually Add Kindle Book to Your iPad or iPhone

When you register your Kindle app on your MacBook Pro with Amazon, all your books should appear in your library.

I don't do this, so this might not work. I have my own net work and 3 devices showed up as devices I could send books to. I'd have to look at the DHCP assignments on my router to see which IP I'd want to send a book to. So you need the IP address of the device (iPad) and enter it -> "Connect/Share" -> "Start Wireless device connection".
click on the book you want to send, then select, "Send to device". Since my Blackberry was the default device, I sent a book to the main memory and the transfer began. I wasn't able to verify the transfer as I don't have the appropriate apps on my Blackberry. iOS is better in that regard.