Consulting firms are grappling with how to adapt their billing practices as artificial intelligence increasingly disrupts traditional service models. The widespread use of AI is prompting a rethinking of the long-standing approach of charging clients based on human time, with many firms exploring alternatives such as fixed-fee subscriptions and outcome-based pricing.

Historically, consulting services have been billed by the hour, essentially renting out human labor. However, as AI tools reduce the variable costs associated with labor, firms face mounting pressure to shift toward pricing strategies more commonly found in software or product businesses. This transition, industry leaders say, is far from straightforward.

One major challenge with moving away from hourly billing is the financial risk firms assume if projects extend beyond their original scope. In fixed-fee arrangements, costs are predetermined, meaning consultants absorb any overruns. This can lead to cash flow difficulties if payment timelines are delayed or the project requires additional resources. Furthermore, disputes may arise over subjective assessments of whether agreed-upon outcomes have been met, potentially straining client relationships.

“There is real pressure to cut prices before fully realizing the benefits of AI-driven efficiencies,” said James O’Dowd, CEO of talent advisory firm Patrick Morgan. Eric Miles, CEO of Baker Tilly, noted that prospective buyers often still evaluate proposals by comparing hourly rates, complicating the adoption of alternative pricing models. He added that continuing with hourly billing risks eroding profit margins because AI creates a business environment marked by high fixed costs and low variable costs, necessitating a fundamental change in the profession’s pricing paradigm.

Leading consulting firms such as McKinsey and Boston Consulting Group are advancing outcome-based pricing models. Shelley Stewart III, a senior partner at McKinsey, recently highlighted in a letter that over 30% of the firm’s global fees are now linked directly to client outcomes—a figure that has steadily increased. Stewart emphasized that outcome-based pricing introduces accountability to consulting, framing it as a forward-looking strategy rather than evidence of decline.

Consulting experts characterize these shifts as urgent responses to maintain viability rather than elective reforms. Pat Petitti, CEO of AI-driven consulting platform Catalant, described the move away from hourly billing as an “existential scramble” triggered by AI’s disruptive impact on traditional revenue streams.

Typical alternatives to hourly fees fall into two categories: fixed-fee pricing, which guarantees set costs for defined deliverables regardless of hours spent, and outcome-based pricing, where compensation depends on achieving agreed-upon performance metrics. While these models aim to align incentives and predict costs, they also heighten pressure on consultancies to deliver more impactful results.

Edward Tian, CEO of GPTZero, warned that the increased demand for output under newer billing models could risk compromising quality if basic fact-checking standards are sacrificed, potentially causing reputational harm to both consulting firms and their clients.

As AI reshapes the consulting landscape, firms continue to experiment with billing strategies, navigating complex trade-offs between financial risk, client expectations, and service quality. The industry’s ability to adapt these models effectively will likely play a critical role in its future sustainability.