Arduino size

Can anyone tell me which is the smallest arduino (in size) with bluetooth feature? i have read about femtoduino but its quiet expensive for me. If anyone have any other arduino in mind please tell me.
Arduino nano is not suitable as its size is bigger for my project

Have a look at the Adafruit Feather series.

I doubt you'll find anything smaller than a Nano which includes Bluetooth.

apart from arduino compatibility can you tell me any other platform which supports bluetooth and are smaller in size...

I don't know. I don't look at the question the same way you do. I look at it as "What bluetooth module can I buy to plug into my Arduino?" I'm not looking to buy boards that have bluetooth and a processor all on one board.

MorganS:
I don't know. I don't look at the question the same way you do. I look at it as "What bluetooth module can I buy to plug into my Arduino?" I'm not looking to buy boards that have bluetooth and a processor all on one board.

Agreed.

One could easily find a Nano clone and a HC-05 combo for less than $10 shipped. It's possible you could find these for $6.

The HC-05 works great with Android devices but I think you need a different board to communicate with an iPhone.

I'm pretty sure Adafruit's BLE devices work with iPhones. Here's their BLE Feather. Adafruit usually has great tutorials on how to use their products.

Considered the WiFi ESP8266? Don’t need an Arduino at all.