Tax policy analysts have awaited more detail on Trump's plan. An analysis earlier this year by the Tax Foundation found his initial proposal could result in a $10 trillion budget shortfall over 10 years.
Ahead of Monday's speech, a Trump tax adviser told USA Today the campaign had reduced the cost of the tax proposals to about a third of the $10 trillion estimate.
Forbes said people would ultimately focus on whether Trump's plan will stimulate growth, provide relief and pad Americans' paychecks.
Despite attempts to appeal to Republicans, Clinton has not yielded on her "left-wing, far Bernie Sanders-like economic program," according to Forbes.
"She wants increases on income taxes, estate taxes, business taxes, gun taxes, soda taxes — every kind of tax," he said.
According to Clinton's campaign page, she would impose a "fair share surcharge" on multimillionaires and billionaires. She would also raise the top estate tax rate to 45 percent and lower the exemption threshold to $3.5 million. She has pledged tax relief for working families.
A study from the nonpartisan Tax Policy Center found that Clinton's plan would raise taxes on the top 1 percent by an average of $78,000 per person while keeping taxes for the rest of Americans largely the same. Clinton has not committed to a gun tax, but has said the policy could help defray the medical and law enforcement costs of gun violence. Earlier this year, she endorsed a Philadelphia proposal to impose a tax on sugary drinks.
— CNBC's Robert Frank contributed to this story.
Correction: This story was revised to correct the military branch in which Humayan Khan served. He was in the U.S. Army.