The economics of a consulting firm: hours, rates, realization and pricing
How one consultant earns money for the firm, why a few points of utilization matter so much, how pricing models share risk, and why this shapes how cases are run.
Industry brief, with a one-minute summary: Professional services and consultingKey takeaways
- Revenue from one person equals available hours times utilization times billing rate times realization.
- In the example, a consultant who costs USD 150,000 brings in USD 283,500.
- Projects are short and priced in advance, often a fixed fee for 6 to 12 weeks, so the team cannot study everything.
- Time is the scarce resource, so the team uses the 80/20 rule: find the few drivers that explain most of the problem and go deep only there.
- Work is split across a small team, so the problem must be broken into parts that do not overlap and together cover everything (MECE), one part per person.
Key idea
Revenue from one person equals available hours times utilization times billing rate times realization. Cost is mostly that person's pay, which does not change when utilization falls. So a small drop in hours billed takes a large bite out of profit, and firms work hard to keep people busy on work clients will pay full price for.
Read the formula from left to right. Available hours are the working hours in a year after holidays (often about 1,800 to 2,000). Utilization is the share of those hours billed. The billing rate is the list price per hour. Realization is the share of the list price actually collected after discounts and write-offs. Multiply them and you get the fees one person brings in. Subtract their pay and benefits and you get their contribution to the firm's shared costs (offices, sales, support staff, training) and to the partners' profit.
Worked case
What one consultant earns for the firm, and what 10 points of utilization cost
The prompt
Harbourline Advisory (a fictional firm in Singapore) has a consultant available for 1,800 hours a year, billed at a standard rate of USD 250 an hour. The firm collects 90 percent of its standard fees (realization). The consultant costs USD 150,000 a year in pay and benefits. What is the yearly contribution at 70 percent utilization, and what happens if utilization falls to 60 percent?
The structure
- Contribution = fees collected minus the cost of the person
- Fees collected = available hours x utilization x billing rate x realization
- Cost of the person = pay and benefits (paid whether or not hours are billed)
- Test the change: redo the fees at the new utilization, cost unchanged
Working it through
1. Hours billed at 70 percent
1,800 available hours at 70 percent.
Hours billed:1,800 × 0.7 = 1,2602. Fees collected at 70 percent
1,260 hours at USD 250, and 90 percent of it collected.
Fees collected (USD):1,260 × 250 × 0.9 = 283,5003. Contribution at 70 percent
Fees minus USD 150,000 of pay and benefits.
Contribution (USD):283,500 - 150,000 = 133,5004. Contribution at 60 percent
1,080 hours billed, the same rate and realization, the same pay.
Contribution at 60 percent utilization (USD):1,800 × 0.6 × 250 × 0.9 - 150,000 = 93,0005. How much contribution is lost
The fall in contribution as a share of the starting contribution.
Fall in contribution (fraction):(133,500 - 93,000) ÷ 133,500 = 0.3034
The recommendation
Harbourline should treat utilization as its first profit lever, because a fall from 70 to 60 percent cuts this consultant's contribution by about 30 percent, from USD 133,500 to USD 93,000. First, fees fall by USD 40,500 while pay stays at USD 150,000, so the whole fall lands on profit. Second, a rise in the rate or in realization of a few points would not make up for it. The risk is pushing utilization so high that people have no time for training or selling. As a next step, track weekly hours on the bench (not billed) by level and office.
Risks: Very high utilization burns people out and raises attrition; Discounts to win work lower realization, which hides behind good utilization figures.
In the example, a consultant who costs USD 150,000 brings in USD 283,500. That gap, repeated across many juniors, pays for the partners, the offices and the sales effort. It is why firms keep a wide base of juniors and why the ratio of staff to partners matters: each partner with a bigger team earns more for the firm, as long as quality holds and the juniors stay busy.
A law firm in London recorded GBP 1,000,000 of work at its standard rates on a matter, but after discounts and write-offs it collected GBP 880,000. What is its realization, as a decimal?
A project team bills 50 partner hours at USD 900, 200 manager hours at USD 450 and 1,200 consultant hours at USD 250. What is the blended rate per hour for the whole team, in USD?
Pricing models: who carries the risk
| Model | How it works | Who carries the risk of more hours | Where it is common |
|---|---|---|---|
| Time and materials | The client pays for every hour at agreed rates, plus expenses | The client | Law, IT projects with unclear scope, staff augmentation |
| Fixed fee | One price for a defined scope, whatever the hours | The firm | Strategy projects, audits, defined IT phases |
| Value based or success fee | Part or all of the fee depends on a result, such as savings or a completed deal | Shared, and the firm also carries the risk of the result | Cost cutting, procurement, deal advice, some Gulf government work |
| Managed service or outcome based | A yearly price to run a service, or a price per unit (per ticket, per invoice processed) | The firm, which gains if it can do the work with fewer hours | IT outsourcing, back office, AI-run services |
So-what
Under time and materials, doing the job with fewer hours lowers revenue. Under fixed fee, value based or outcome pricing, it raises profit. That is why AI pushes firms away from charging by the hour.
Worked case
A fixed fee project that runs over, and how value based pricing compares
The prompt
Cedarway Consulting (fictional) agreed a fixed fee of USD 600,000 to redesign a Saudi retailer's buying process. It planned 2,000 team hours at a cost of USD 150 per hour (pay and benefits). The work took 25 percent more hours than planned. What was the planned margin, and the margin after the overrun? An alternative offer was 10 percent of the first year's savings, which turned out to be USD 8 million. Compare.
The structure
- Project margin = fee minus the cost of the hours used
- Cost of hours = hours used x cost per hour
- Fixed fee: the fee stays the same when hours run over
- Value based: fee = share of savings, whatever the hours
Working it through
1. Planned cost
2,000 hours at USD 150.
Planned cost (USD):2,000 × 150 = 300,0002. Planned margin
Fee minus planned cost, as a share of the fee.
Planned margin (fraction):(600,000 - 2,000 × 150) ÷ 600,000 = 0.53. Cost after the overrun
25 percent more hours: 2,500 hours at USD 150.
Actual cost (USD):2,000 × 1.25 × 150 = 375,0004. Margin after the overrun
The fee does not move, so the extra cost comes out of margin.
Actual margin (fraction):(600,000 - 375,000) ÷ 600,000 = 0.3755. Value based fee
10 percent of USD 8 million of savings.
Value based fee (USD):8,000,000 × 0.1 = 800,0006. Value based margin with the same hours
USD 800,000 minus the actual cost of USD 375,000.
Value based margin (fraction):(800,000 - 375,000) ÷ 800,000 = 0.5313
The recommendation
Cedarway should price its next buying project on value, with a floor, because the fixed fee margin fell from 50 to 37.5 percent when hours ran 25 percent over, while a 10 percent share of the USD 8 million savings would have paid USD 800,000 and a margin of about 53 percent. First, the firm carried all the risk of extra hours under the fixed fee. Second, the savings were measurable, which is what value based pricing needs. The risk is that savings fall short and the fee falls with them. As a next step, agree how savings are measured before work starts.
Risks: Savings can be hard to measure and easy to dispute; A fee linked to results can tempt a firm to chase quick savings over lasting change.
Why this shapes how cases are run
- Projects are short and priced in advance, often a fixed fee for 6 to 12 weeks, so the team cannot study everything. It starts with a hypothesis (a best guess at the answer) and tests it, instead of collecting all the data first.
- Time is the scarce resource, so the team uses the 80/20 rule: find the few drivers that explain most of the problem and go deep only there.
- Work is split across a small team, so the problem must be broken into parts that do not overlap and together cover everything (MECE), one part per person. That is the issue tree you draw in a case.
- The partner sells the next project from the answer to this one, so the final message must be clear, backed by numbers and lead to action: the recommendation you give at the end of a case.
- Juniors are billed at a price well above their pay only if clients see real value, so firms hire people who can structure a messy problem, do quick and correct math, and explain the answer simply. The case interview tests exactly those skills.
A firm moves a client from time and materials to a fixed fee, then uses AI tools to finish the work with 30 percent fewer hours. What happens to its profit on the project?
Sources for this lesson (3)
- Recognized public explanations of case-interview concepts and frameworks
- Summary of the SPI Research 2026 Professional Services Maturity Benchmark (509 firms, data for 2025)
- Thomson Reuters Institute, Law Firm Rates Report 2026 analysis, November 2025
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