At the biggest toy industry trade show in the Western Hemisphere this weekend, toy makers, as usual, displayed seemingly endless rows of stuffed animals, action figures and puzzles, hoping to entice retailers to pick their products.

But this year, the chatter at Toy Fair New York was dominated not by the next Barbie, but a larger game, one of global tactics, that could make most toys more expensive for U.S. consumers.

Almost 80 percent of toys sold in the United States are made in China. Last week, just as toy vendors from across the United States and dozens of other countries started to flock to the Jacob K. Javits Convention Center for the annual toy fair, President Trump announced a 10 percent tariff on Chinese goods that would come on top of the 10 percent he already imposed a month ago.

Companies big and small — from family-owned brands to household names — are trying to figure out how to manage the new costs related to tariffs. Stationed at a booth lined with plush stuffed animals, Linda Colson, the vice president of sales at Mary Meyer Corporation, said her company, based in Vermont, was in a state of paralysis over pricing. “We don’t know what to do,” she said. “I think a lot of people in this building are just waiting to see what everybody else is doing.”

Jay Foreman, the chief executive of Basic Fun, a toy manufacturer and distributor in Florida, sells to retailers including Walmart and Target. After Mr. Trump ordered the 10 percent tariff on China in February, Mr. Foreman started thinking of ways to avoid passing those costs onto his customers. So last Wednesday, he met with his company’s board of directors to devise a plan that would split the burden: the company, its factories in China and its retail customers would each absorb 3.5 percent of the added cost.

But just hours later, Mr. Foreman tuned into CNBC and heard Mr. Trump declare that new tariffs on China could jump to a total of 20 percent this week. The company’s plans “went right out the window,” said Mr. Foreman, whose company employs about 110 people in the United States and a total of 165 people globally.

“Now, those can’t be absorbed, and that additional tariff has to be passed onto the consumer,” he added. “It tipped the domino.”

The Tonka Mighty Dump Truck, which Basic Fun makes under a license from Hasbro, currently retails for $29.99. That price will probably increase between $5 and $10 for consumers, Mr. Foreman said.

Some of the bigger companies at the convention expressed confidence that their Chinese suppliers would absorb a portion of the added costs, as factories would not want to lose business.

Safari, which sells animal figurines, produces about 90 percent of its products in China, said Danny Falero, the company’s director of marketing, and manufacturers have said they are willing to make some concessions. He emphasized that his company did not intend to raise prices unless Mr. Trump’s policies went into effect.

“It’s slightly theater, so let’s see what actually lands, and then we’ll make adjustments based on that,” Mr. Falero said.

Looming tariffs were weighing heavily on Luis Prior, who owns Meavia Toys, a small company in Corbin, Ky. His three-year-old business designs sensory toys for children with special needs and are sold to teachers, hospitals and museums.

Mr. Prior said that regardless of whether tariffs on China stayed at 10 percent or doubled on Tuesday, he would have to raise his prices. But the uncertainty has made it impossible to make any specific pricing decisions, he said. When he returns home from the convention this week, Mr. Prior plans to go through his products, item by item, and reassess.

“Exhaustion,” Mr. Prior said. “That’s the only way I can describe it.”

Three billion toys are sold in the United States each year, generating $42 billion in sales and supporting nearly 700,000 jobs, according to the Toy Association, a trade group representing the U.S. toy industry.

The association has been lobbying for an exemption from Mr. Trump’s broad tariffs, pointing in part to the fact that small businesses make up roughly 96 percent of the industry, said Greg Ahearn, the group’s chief executive. During Mr. Trump’s first term in the White House, he had imposed 10 to 25 percent tariffs on many Chinese products — but he backed down from tariffs on toys, among other consumer goods.

While most toys are made in China, some manufacturing has moved to Mexico in recent years, but Mr. Trump also said that the 25 percent tariff he had imposed on Mexico and Canada would go into effect on Tuesday.

The Toy Association has been visiting senators’ offices and pushing to get its message to people inside the Trump administration, Mr. Ahearn said, as well as communicating with its members daily to share the latest updates on tariffs.

Mr. Trump’s announcement of an additional tariff on China coincided with Mr. Ahearn’s preparations for the Toy Fair. “It wasn’t good, and now it’s unbearable for us as an industry,” Mr. Ahearn said, adding that a 20 percent tariff will inevitably be passed onto consumers.

In an interview with CNBC on Monday, the White House trade adviser, Peter Navarro, doubled down on Mr. Trump’s tariff plans, saying their effect on consumer prices would be “second order small” when taking in account the administration’s simultaneous plans to deregulate industry, reduce the size of the federal government and expand energy production.

“I don’t see the president wavering on any of this,” he said.

Five years ago, Sharon Azula and her husband started a company called the Tooth Brigade selling tooth-fairy pillows.Last summer, they lowered the retail price for a pillow — a small stuffed animal with a tooth pouch — to $14, down from $16, which helped boost demand.

Tariffs, especially if they amount to 20 percent, are likely to force Ms. Azula to raise prices again, since everything they sell is manufactured in China. When they started the brand, she and her husband wanted to manufacture their products in the United States, but it was too expensive, she said.

Now, motioning to a pillow at her Toy Fair booth, Ms. Azula said she was worried that higher prices could sink the business.

“When I’m here, I try not to think about it,” she said, tearing up. “But when you try to think about what the future is going to be — I don’t know. I just don’t know.”