You Do Need power plug adapter while traveling from United States of America (US) USA to Singapore.

Here is Why You Need An Adapter

The outlet and plug type used in Singapore is G and in United States of America (US) USA are A and B. This is how they look like.

United States of America (US) USA

In United States of America (US) USA, outlets of type A and B are in use.

Type A

Type B

Singapore

In Singapore, outlets of type G are in use.

Type G