The deal comes amid considerable upheaval in the market for financial advice, including tougher regulation in the US and UK and evidence that millennials would prefer smartphone apps to conversations with an adviser.
Robo-advisers combine information about a customer's investment goals, income and tax situation to generate automated portfolios, charging lower fees than a broker or financial adviser.
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Last year, Fidelity began offering a product from Betterment, one of the most successful robo-advisers to date in terms of assets under management, to the 3,000 financial advisers who use its Fidelity Institutional Wealth Services division.
FutureAdvisor was founded by Microsoft colleagues Bo Lu and Jon Xu and developed at the Y Combinator start-up programme in San Francisco. Last year, it raised $15.5 million at a reported $75 million valuation; its venture capital backers include Sequoia and Canvas Venture Fund.
Frank Porcelli, head of BlackRock's US wealth advisory unit, said: "I have two 20-something boys and I don't know, in an age of texts and chat, that they are going to sit down with a financial adviser. They might prefer digital advice.
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"Wherever the advice market goes, BlackRock wants to be there, and one thing we know is that five and 10 years from now, there will be more people using digital advice platforms than do today."
BlackRock Solutions is separate from the company's $4.7 trillion asset management business, and sells consulting services and software, including risk management systems, to other financial institutions.
FutureAdvisor will remain an "open architecture" platform, meaning it will be able to recommend more than just BlackRock funds, the company said.