U.S. President Donald Trump wants the American working class to take his word for it when it comes to who would benefit from his administration's plans for tax reform.

"It's not good for me. Believe me," the billionaire president told a crowd in Indiana on Wednesday.

Yet tax policy analysts beg to differ.

They say the nine-page wish list omits big details such as specifics on income thresholds for three or possibly four new tax brackets, the potential size of an increase to the child tax credit, and details about business tax provisions. That makes it difficult to determine to what extent the long-awaited plan would help the middle class.

What does seem certain, they say, is the plan would benefit Trump personally in at least two ways — by getting rid of the estate tax that hits only the wealthiest Americans, and by bringing the top rate down to 35 per cent from 39.6 per cent.

"Donald Trump will benefit a great deal from the lowering of the tax, we know that," said Michael Graetz, a former special counsel at the Treasury Department.

"We know what the benefits are for the rich through the repeal of the estate tax and the lower rates of high-income business owners through their partnerships," he said. "But what we really don't know much about is the nature of benefits for the middle class."

Graetz, who teaches at Columbia University, described the Republican plan as "a frame without a picture."

A protester holds a sign during demonstrations as Trump delivers a speech on tax reform in Indianapolis. (Bryan Woolston/Reuters)

Len Burman and his team at the Tax Policy Center are working to cost out the plan within the next few days. Another Washington tax policy research organization, the Tax Foundation, said it won't even attempt its preliminary analysis until more details surface.

But the non-partisan Committee for a Responsible Federal Budget estimates the plan will amount to $5.8 trillion in tax cuts over 10 years. Factoring in revenue offsetting measures such as the scrapping of some tax breaks, the committee projects the plan would increase the federal debt by more than $2 trillion over the next decade.

Broadly, the latest Republican tax plan seeks to:

Cut the corporate tax rate to 20 per cent , down from 35 per cent. Conservatives are framing the lower corporate tax rate as something that will increase investment and help businesses create jobs.

, down from 35 per cent. Conservatives are framing the lower corporate tax rate as something that will increase investment and help businesses create jobs. Lower the top tax rate for so-called "pass-through" businesses to 25 per cent. These businesses, such as partnerships, S corporations or limited liability companies (LLCs), are only taxed on individual income.

These businesses, such as partnerships, S corporations or limited liability companies (LLCs), are only taxed on individual income. Eliminate the state and local tax deduction for individuals , thus taking away a break for taxpayers in highly taxed states such as New York, New Jersey and California.

, thus taking away a break for taxpayers in highly taxed states such as New York, New Jersey and California. Scrap the alternative minimum tax (AMT) , which was designed to prevent high-income earners from using loopholes to pay zero tax.

, which was designed to prevent high-income earners from using loopholes to pay zero tax. And repeal the estate tax, a provision that affects very wealthy people who leave money to their heirs. The tax is currently set at 40 per cent.

The left-leaning Center on Budget and Policy Priorities argues that repealing the estate tax, also known as the "death tax," would give rich estates a windfall in tax cuts. At the same time, a CBPP reports says, "it would do virtually nothing for small farms and businesses" and exacerbate income inequality.

The tax affects only a small portion of rich families that are worth more than $5.49 million.

"The estate tax is an interesting animal," said the Tax Foundation's Kyle Pomerleau. "It creates a lot of controversy, but it doesn't create a lot of revenue."

The estate tax brought in $19.3 billion in 2014, according to the Office of Management and Budget, accounting for 0.6 per cent of total federal revenue, which is $3 trillion.

When it was introduced in the 1960s, the alternative minimum tax was meant to clamp down on tax filers who took advantage of deductions to avoid paying taxes completely. In the decades since, it has gone through enough updates that it now also hits some upper-middle-income taxpayers.

Pomerleau said it's conceivable that a taxpayer who earns $150,000 a year could be affected by the AMT, "but those cases aren't the overwhelming rule." The tax tends to kick in around $180,000 and above, "so we're not talking about real middle-income taxpayers who are earning $40,000 to $50,000 a year — they're not subject to the AMT."

Senate majority leader Mitch McConnell called Trump's tax efforts a 'once-in-a-generation opportunity to fundamentally rethink our tax code.' (J. Scott Applewhite/Associated Press)

As Trump has not released his tax returns, it's difficult to discern how the AMT would impact him. However, a line from his leaked 2005 return indicates the AMT accounted for $31.3 million in additional taxes, what the New York Times called "a vast bulk" of his federal income taxes that year.

One feature of the Republican tax proposal that could benefit the middle class is a doubling of the "standard deduction" to $12,000 for individuals. The standard deduction is the fixed-amount deduction in lieu of itemized deductions. The increase would simplify tax filing for middle-income earners.

Cuts complexity of code

While the president has reportedly tried to sell the plan as a populist tax cut rather than "reform," Steve Bell, a senior adviser at the Bipartisan Policy Center in Washington, said he considers it reform because it attempts to simplify the tax code in a big way.

"It does reduce the complexity of the code," he said. "It means fewer people have to file, and it does help some people on the lower-income end. And no doubt about it, it does help people on the higher-income end because it does get rid of the death tax and the AMT."

Trump says the current tax system is a 'relic' and a 'colossal barrier' standing in the way of the nation's economic comeback. He says his tax proposal will help middle class families save money and will eliminate loopholes that benefit the wealthy. (Michael Conroy/Associated Press)

As for whether the Republican tax plan would help cut the president's taxes, the director of Trump's National Economic Council deflected reporter questions on Thursday, saying American taxpayers are more concerned with their own financial positions.

"American taxpayers care about what they take home," Gary Cohn said. "They care about what they have to spend."