How to check 18650 battery capacity ( easy method )

If you have old laptop batteries try to recycle and reuse for power bank, rechargeable torch and your project.but problem is batteries have different capacity. if you try to charge all battery in the same time some batteries overcharge and some batteries not charging completely.so you want check capacity of each battery.after you can make complete battery pack with full efficient .now I teach you simple way measure18650 battery capacity u