Why does my HTC take a long time to charge?

[Robb Stark1]

I have a HTC One M8 and currently using a Samsung charger (5V-2A) to charge my phone, from 20% it takes 2.5 hours to fully charge and 3hours from 0%. Is this a normal charging time?

 

[Claude Speed]

I have a HTC One M8 and currently using a Samsung charger (5V-2A) to charge my phone, from 20% it takes 2.5 hours to fully charge and 3hours from 0%. Is this a normal charging time?

Why not just use a charger that came with your phone?

 

[Robb Stark1]

Because the original HTC charger only outputs 1A so it charges a lot slower