Amazon is also hoping to attract new customers to Amazon Prime, which costs $119 a year, since other online retailers offer two-day delivers for free.
However, in recent months the company has been expanding the number of zip codes and items eligible for the one-day shipping times, Olsavsky said.
Also, an accounting change a year ago, makes it hard to compare 2018 to 2019, according to Brian Wieser, GroupM's global president business intelligence.
It did not say when delivery times would be cut but said it expects to make "steady progress" this year.
The company's loyal customer base has drawn merchants to sell and increasingly advertise through its site in exchange for fees, helping Amazon transform from a largely low-margin retail business to a more and more lucrative marketplace. Amazon did not comment on whether drones will fuel this default one-day speed boost for paying Amazon Prime subscribers' deliveries.
Amazon kept a lid on delivery costs in the period ended March 31, spending $7.3 billion in the quarter. Sales for Amazon Web Services (AWS) rose 41 percent to $7.7 billion in the first quarter.
In the same time a year ago, it reported net income of $1.63 billion, or $3.27 per share.
The company plans to spend more to roll out benefits to global Prime members.
Sales in Amazon's "other" segment, which is mostly advertising, increased 34 percent, to 2.72 billion. "The days of stellar uplifts have long since disappeared and it is clear that Amazon is now in a different era - one characterized by more modest gains".
As the company has grown, it has become a clearinghouse for smaller businesses.
The company forecast net sales of between $59.5 billion and $63.5 billion for the second quarter, the midpoint of which was below analysts' average estimate of $62.37 billion, according to IBES data from Refinitiv.
The CFO said Amazon will use its own AMZL logistics as well as third-party carriers to meet its next-day promise.