Highlighted areas show what parts of President Trump’s 2005 tax return could have been affected by his new tax plan.

An updated version of this article was published on Sept. 28, 2017.

President Trump could save tens of millions of dollars in a single year under his proposed changes to the tax code, a New York Times analysis has found.

On Wednesday, the White House announced a sweeping plan to cut a variety of taxes that would overwhelmingly benefit the wealthy. The estimated savings for Mr. Trump rely on his income and other information from his 2005 federal tax return and compare what his tax burden would be under the proposal to current law. Mr. Trump’s 2005 return is the most recent available publicly and was released in March by the former New York Times reporter David Cay Johnston.

These estimates, done with the help of Robert Willens, an accounting expert, provide a view into how high-income earners like Mr. Trump could benefit from the proposal. They do not take into account other potential planning techniques that wealthy taxpayers often use.

When asked at a news conference on Thursday, Sean Spicer, the White House press secretary, did not directly address how the plan would affect Mr. Trump. “The president’s plan right now is something that every American should worry, hopefully, about how it’s going to affect them,” Mr. Spicer said.

Savings of $31 million from repealing the Alternative Minimum Tax

Line 45 of Mr. Trump’s 2005 tax return shows he paid $31.3 million because of the Alternative Minimum Tax.

The decades-old Alternative Minimum Tax is meant to prevent America’s wealthiest from using deductions to pay very low or no federal income tax. In 2005, it accounted for about 80 percent of Mr. Trump’s overall income tax payment. His plan to repeal the tax would save him $31.3 million.

Savings of about $27 million from taxing certain types of business income at 15 percent

Lines 12 and 17 of Mr. Trump’s tax return show the income he earned from businesses, rental real estate and other kinds of business partnerships, totaling $109.8 million.

Mr. Trump’s proposed changes could allow individuals to qualify for a significantly reduced tax rate of 15 percent on certain types of income they receive through business partnerships and similar entities. High-income earners currently face tax rates as high as 39.6 percent.

Mr. Trump could save as much as $10.4 million on business income and $16.6 million on income from real estate and other kinds of partnerships under this plan, compared with his tax burden under current law. (In 2005, much of this taxable income was offset by a $103.2 million write-down in business losses.)

Increase of $3 million to $5 million in taxes from repealing most deductions

Line 40 shows Mr. Trump itemized his deductions instead of using the standard tax deduction, claiming $17 million.

Mr. Trump would probably lose most of the deductions he reported in 2005. Depending on his effective tax rate under the proposal, Mr. Trump could pay roughly $3 million to $5 million more in taxes.

As a resident of New York City, the largest portion of Mr. Trump’s deductions probably came from his local and state income taxes. Under his proposal, only mortgage interest, charitable giving and retirement contributions would be deductible.

Savings of about $1.5 million from repealing the health care tax on investment income

Lines 8a, 9a and 13 show different kinds of investment income Mr. Trump earned in 2005, totaling $42 million.

In the Affordable Care Act, Congress introduced a 3.8 percent tax on investment income, which took effect in 2013. Repealing the tax could save about $1.5 million for someone with Mr. Trump’s investment income.

Savings of about $0.5 million from cutting the highest tax rate

Lines 7, 8a and 9a show $10.8 million in wages, taxable interest and ordinary dividends that Mr. Trump earned in 2005.

The proposal to reduce the highest tax rate from 39.6 percent to 35 percent would save high-income earners similar to Mr. Trump a relatively small amount compared with the repeal of the Alternative Minimum Tax. The $500,000 in savings is a rough estimate because Mr. Trump has not specified income levels for his proposed tax brackets.

Savings of about $1.2 billion from repealing the estate tax