• Tax rates. The new law imposes a new tax rate structure with seven tax brackets: 10%, 12%, 22%, 24%, 32%, 35%, and 37%. The top rate was reduced from 39.6% to 37% and applies to taxable income above $500,000 for single taxpayers, and $600,000 for married couples filing jointly.
• The rates applicable to net capital gains and qualified dividends were not changed. The "kiddie tax" rules were simplified. The net unearned income of a child subject to the rules will be taxed at the capital gain and ordinary income rates that apply to trusts and estates. Thus, the child's tax is unaffected by the parent's tax situation or the unearned income of any siblings.
• Standard deduction. The new law increases the standard deduction to $24,000 for joint filers, $18,000 for heads of household, and $12,000 for singles and married taxpayers filing separately.
• Exemptions. The new law suspends the deduction for personal exemptions. Thus, starting in 2018, taxpayers can no longer claim personal or dependency exemptions.
• New deduction for "qualified business income." Starting in 2018, taxpayers are allowed a deduction equal to 20 percent of "qualified business income," otherwise known as "pass-through" income, i.e., income from partnerships, S corporations, LLCs, and sole proprietorships. The income must be from a trade or business within the U.S. Investment income does not qualify, nor do amounts received from an S corporation as reasonable compensation or from a partnership as a guaranteed payment for services provided to the trade or business. The deduction is not used in computing adjusted gross income, just taxable income. For taxpayers with taxable income above $157,500 ($315,000 for joint filers), (1) a limitation based on W-2 wages paid by the business and depreciable tangible property used in the business is phased in, and (2) income from the following trades or businesses is phased out of qualified business income: health, law, consulting, athletics, financial or brokerage services, or where the principal asset is the reputation or skill of one or more employees or owners.
• Child and family tax credit. The new law increases the credit for qualifying children (i.e., children under 17) to $2,000 from $1,000, and increases to $1,400 the refundable portion of the credit. It also introduces a new (nonrefundable) $500 credit for a taxpayer's dependents who are not qualifying children. The adjusted gross income level at which the credits begin to be phased out has been increased to $200,000 ($400,000 for joint filers).
• State and local taxes. The itemized deduction for state and local income and property taxes is limited to a total of $10,000 starting in 2018.
• Mortgage interest. Under the new law, mortgage interest on loans used to acquire a principal residence and a second home is only deductible on debt up to $750,000 (down from $1 million), starting with loans taken out in 2018.
• No longer any deduction for interest on home equity loans, regardless of when the debt was incurred.
• Miscellaneous itemized deductions. There is no longer a deduction for miscellaneous itemized deductions which were formerly deductible to the extent they exceeded 2 percent of adjusted gross income. This category included items such as tax preparation costs, investment expenses, union dues, and unreimbursed employee expenses.
• Medical expenses. Under the new law, for 2017 and 2018, medical expenses are deductible to the extent they exceed 7.5 percent of adjusted gross income for all taxpayers. Previously, the AGI "floor" was 10% for most taxpayers.
• Casualty and theft losses. The itemized deduction for casualty and theft losses has been suspended except for losses incurred in a federally declared disaster.
• Overall limitation on itemized deductions. The new law suspends the overall limitation on itemized deductions that formerly applied to taxpayers whose adjusted gross income exceeded specified thresholds. The itemized deductions of such taxpayers were reduced by 3% of the amount by which AGI exceeded the applicable threshold, but the reduction could not exceed 80% of the total itemized deductions, and certain items were exempt from the limitation.
• Moving expenses. The deduction for job-related moving expenses has been eliminated, except for certain military personnel. The exclusion for moving expense reimbursements has also been suspended.
• Alimony. For post-2018 divorce decrees and separation agreements, alimony will not be deductible by the paying spouse and will not be taxable to the receiving spouse.
• Health care "individual mandate." Starting in 2019, there is no longer a penalty for individuals who fail to obtain minimum essential health coverage.
• Alternative minimum tax (AMT) exemption. The AMT has been retained for individuals by the new law but the exemption has been increased to $109,400 for joint filers ($54,700 for married taxpayers filing separately), and $70,300 for unmarried taxpayers. The exemption is phased out for taxpayers with alternative minimum taxable income over $1 million for joint filers, and over $500,000 for all others.

• New deduction for pass-through income. The new law provides a 20% deduction for "qualified business income," defined as income from a trade or business conducted within the U.S. by a partnership, S corporation, or sole proprietorship. Investment items, reasonable compensation paid by an S corporation, and guaranteed payments from a partnership are excluded. The deduction reduces taxable income but not adjusted gross income. For taxpayers with taxable income above $157,500 ($315,000 for joint filers), (1) a limitation based on W-2 wages paid by the business and the basis of acquired depreciable tangible property used in the business is phased in, and (2) the deduction is phased out for income from certain service related trades or businesses, such as health, law, consulting, athletics, financial or brokerage services, or where the principal asset is the reputation or skill of one or more employees or owners.
• Corporate tax rates reduced. One of the more significant new law provisions cuts the corporate tax rate to a flat 21%.
• Alternative minimum tax repealed for corporations. 
• Alternative minimum tax credit. Corporations are allowed to offset their regular tax liability by the AMT credit.
• Net Operating Loss (“NOL”) deduction modified. Under the new law, generally, NOLs arising in tax years ending after 2017 can only be carried forward, not back. However, a two-year carryback for certain farming losses is allowed.
• Limit on business interest deduction. 
• Domestic production activities deduction (“DPAD”) repealed. 
• New fringe benefit rules. The new law eliminates the 50% deduction for business-related entertainment expenses. The pre-Act 50% limit on deductible business meals is expanded to cover meals provided via an in-house cafeteria or otherwise on the employer's premises. Additionally, the deduction for transportation fringe benefits (e.g., parking and mass transit) is denied to employers, but the exclusion from income for such benefits for employees continues. However, bicycle commuting reimbursements are deductible by the employer but not excludable by the employee. Last, no deduction is allowed for transportation expenses that are the equivalent of commuting for employees except as provided for the employee's safety.
• Family and medical leave credit. A new general business credit is available for tax years beginning in 2018 and 2019 for eligible employers equal to 12.5% of wages they pay to qualifying employees on family and medical leave.
• Increased Code Sec. 179 expensing. The new law increases the maximum amount that may be expensed under Code Sec. 179 to $1 million.
• Bonus depreciation. Under the new law, a 100% first-year deduction is allowed for qualified new and used property acquired and placed in service after September 27, 2017 and before 2023. Pre-Act law provided for a 50% allowance, to be phased down for property placed in service after 2017.
• Depreciation of qualified improvement property. The new law provides that qualified improvement property is depreciable using a 15-year recovery period and the straight-line method. There are no longer separate requirements for leasehold improvement property or restaurant property.
• Luxury auto depreciation limits. Under the new law, for a passenger automobile for which bonus depreciation (see above) is not claimed, the maximum depreciation allowance is increased to $10,000 for the year it's placed in service, $16,000 for the second year, $9,000 for the third year, and $5,760 for the fourth and later years in the recovery period.
• Like-kind exchange treatment limited. Under the new law, the rule allowing the deferral of gain on like-kind exchanges of property will be limited to cover only like-kind exchanges of real property not held primarily for sale. Under a transition rule, the pre-TCJA law applies to exchanges of personal property if the taxpayer has either disposed of the property given up or obtained the replacement property before 2018.

• Rates were lowered and the taxable income will be subject to the four tax brackets described above, taxed at 10%, 24%, 35% and 37% tax rates. 
• Estate and gift tax exemption. Effective for decedents dying, and gifts made, in 2018, the estate and gift tax exemption has been increased to $11.2 million ($22.4 million for married couples)