The amount needed for Emirates Business class upgrade depends on various factors. In case you want to know about the cost required to upgrade to business class, follow these steps:

Go to the Emirates website and then manage your booking section
Click on Upgrade your flights and enter 'last name and booking reference number, retrieve the booking
Select the ticket you want to upgrade and choose the upgrade options
Select the class you wish to upgrade to and follow the prompts
On the payments page, you will be able to see the upgrade prices; you can pay for it or exit the screen

Does Emirates give a free business-class upgrade?

Yes! You can get free Emirates business-class upgrades; consider the points below:

If you are a member of the Emirates Skywards program, you can get free or discounted upgrades. You can also use the miles you earn to pay for upgrades online.
If you have an elite statue, you might get a complimentary upgrade if it is available before boarding.
You can also arrive at the airport on time and speak to the staff if business class seats are empty and the airline allows free upgrades.

Is upgrading to business class cheaper at the airport?

The airlines mainly disclose the upgrade inventory near departure and often sell the seats at discounted prices. So, if you are at the airport, you can immediately get the benefits. Besides, by being flexible with your travel plan, you can enjoy upgrading to business class at the airport at a cheaper price. However, it is believed that you should not wait for the last moment in case you desperately want an Emirates business class upgrade. Because the seats are limited, getting the desired one at the airport may be difficult.