Few companies have announced large-scale layoffs, though they are making some adjustments that workers are starting to notice. Companies are slowing hiring, leaving roles unfilled and scrutinizing spending on consultants and contractors.

As they outlined cost-cutting measures on earnings conference calls in recent days, many CEOs used language that boils down to a corporate version of the Serenity Prayer.

“Control the controllables and try to help mitigate some of the things we can’t control,” Norfolk Southern Chief Executive Officer Mark George told investors and analysts as he cited plans to wring savings out of fuel and labor costs, among other areas.

The Atlanta-based freight railroad said that while there is no clear information on how tariffs might affect its revenue, it has been under financial pressure to be more efficient after several disruptions in recent years. They include the East Palestine, Ohio, train derailment, a proxy battle with an activist investor, and an unplanned leadership change.

International Business Machines CEO Arvind Krishna said the technology company was “focused on areas we can control,” including productivity initiatives throughout the company. PepsiCo CEO Ramon Laguarta said the company is “controlling what we can” by, in part, making its supply chain more efficient. Other executives didn’t give specifics but said they were reviewing a range of possible actions.

The White House’s on-again, off-again tariff directives mean companies have little predictability to make moves such as greenlighting investments or redistributing longstanding supply chains. But they can resort to the time-honored playbook of cutting costs in highly uncertain times.

Some corporate bosses are stepping up existing efforts. Hasbro said it would accelerate a multiyear plan to cut $1 billion in costs, with the toy maker now looking to find $175 million to $225 million in savings this year. In the past, the company found cost savings by changing designs to make products cheaper to build, such as Jenga blocks that now use a single type of wood.

Dow said it plans to cut about $6 billion of costs after weak demand led to a first-quarter loss. The company’s cost review will focus on pulling back on capital expenditures. Dow will delay construction of a zero-emissions ethylene plant in the Canadian province of Alberta, and is rethinking plans for chemical plants in Germany and the U.K.

At Principal Financial Group, the interim CFO, Joel Pitz, said the company intends to watch expenses more closely, such as spending on consultants and employee travel, as well as delaying hiring.

By cutting costs and streamlining operations internally, companies can take action now, even if they have little ability to predict what happens next, according to executives and corporate advisers.

“It’s a good opportunity to say: Are we as efficient and effective as we could be?” said Ron Williams, a former CEO of the health insurer Aetna, who remains in touch with executives across industries.

Many companies are trying to be mindful not to make drastic cuts that could hamstring businesses should trade tensions ease or the economy fare better than expected later this year.

“A lot of companies are not looking at layoffs per se, because they lived through Covid and lost a lot of talent” that proved difficult to rehire when the economy rebounded, Williams said. “Without pulling dramatic levers, they are looking at those expenditures, saying, ‘Defer until we get more clarity.’”

At GE Aerospace, CEO Larry Culp said in an interview that he wants to avoid cuts to research and development or reductions in areas that could destabilize the company’s supply chain. Instead, executives are combing through balance sheets for reductions in areas ranging from corporate travel and back-office expenses to hiring. GE Aerospace estimated that tariffs would cost it $500 million this year.

“There’s always more opportunity” to cut costs, Culp said.

Some companies are cutting jobs. The staffing firm Robert Half said it eliminated an unspecified number of administrative and corporate staff positions to reduce its overhead costs. The savings: $80 million.

“We came out of the election, there was a surge in business confidence. Our discussions and the tenor of our discussions with our clients was improving, and so we were quite optimistic,” CEO M. Keith Waddell told investors. “And that changed.”

Write to Chip Cutter at chip.cutter@wsj.com