Tax benefits for small business as part of the Reagan administration's economic recovery plan will total about $2.3 billion this year and $8.6 billion by 1986, according to the Commerce Department.

Small and minority businesses should benefit from special rate reductions for small companies, the reduction or elimination of estate and gift taxes, increases in tax-deductible retirement savings for the self-employed and accelerated cost recovery available to all businesses, Commerce officials said.

Commerce, through its Minority Business Development Agency, last week sponsored a briefing for minority-owned businesses to explain some of the tax breaks that may interest them the most.

During the White House Conference on Small Business almost two years ago small business owners pushed for changes in estate tax laws to make it easier and less costly to pass on businesses to children or other family members when the owners die. One of the provisions of the Economic Recovery Tax Act will allow transfers of up to $600,000 tax free and reduce the top estate tax rate from 70 percent to 50 percent. No transfer tax will be imposed on gifts and bequests between spouses, the Commerce Department said.

Another provision small business can take advantage of is increased investment credit for used property, the Commerce Department said. Many small businesses conserve scarce capital by buying used machinery and equipment, Commerce said. The amount of those purchases eligible for an investment tax credit will increase from $100,000 to $125,000 for 1981-1984 and $150,000 after that.

Limits on deductions for retirement plan contributions for the self-employed will increase from $7,500 to $15,000. New businesses will be helped by a provision allowing employes to be taxed at lower rates when they sell stock acquired through incentive stock option plans. This law is intended to help businesses attract workers who otherwise might be too expensive, the Commerce Department said.