Contribution margin per hour
What is a billable rate spread calculator?
A billable rate spread calculator measures the difference between what a professional services firm charges clients per hour and what it costs to deliver that hour. It helps agencies, consultancies, MSPs, implementation teams, law firms, and service businesses evaluate rate-card economics, delivery margin, loaded labor cost, contractor profitability, and whether a billable rate is high enough to support target gross margin.
Billable rate spread and delivery margin formula
The billable spread formula subtracts fully loaded cost per hour from the client bill rate. Delivery margin then divides that spread by the bill rate to show contribution margin as a percentage of invoiced revenue.
Spread per billable hour = Client bill rate - Fully loaded cost; Delivery margin % = ((Client bill rate - Fully loaded cost) / Client bill rate) x 100- Use client-facing bill rate when evaluating pricing.
- Use fully loaded delivery cost, not raw wage or salary divided by hours.
- For realized margin, adjust bill rate for discounts, write-offs, non-billable time, and utilization.
Inputs explained
Billable spread is most useful when rate and cost are tied to the same role, grade, geography, staffing mix, and pricing policy.
- Client bill rate ($/hr)
- The hourly rate charged to the client for the consultant, agency team member, contractor, or blended delivery role. Use the actual realized rate if discounts, retainers, write-offs, or negotiated rate cards reduce the published rack rate.
- Fully loaded cost ($/hr)
- The internal cost of delivering one hour, including salary or contractor cost, payroll taxes, benefits, PTO, bench time, tools, equipment, training, and allocated overhead according to your finance policy.
- Delivery margin %
- The percentage of billable revenue left after covering loaded delivery cost. This helps compare rate-card health across roles, clients, projects, and staffing models.
- Spread per billable hour
- The dollar contribution generated by each billable hour before sales cost, recruiting, firm overhead, partner distributions, taxes, and other below-gross-margin expenses.
Example billable rate spread calculation
If a consulting team bills clients at $175 per hour and the fully loaded delivery cost is $92 per hour, the spread is $83 per billable hour. Delivery margin is about 47.4% before discounts, write-offs, bench time, SG&A, sales commissions, and partner profit sharing. If realization drops below the rate card, the true margin will be lower.
Contribution margin per hour
(Bill rate − loaded cost) ÷ bill rate × 100
Want a similar calculator on your website?
Describe your fields and formula in plain English, match your brand, and embed the widget anywhere—WordPress, Webflow, Shopify, or custom HTML. Capture leads when you're ready.
How to calculate billable spread and delivery margin %
- Pull “Client bill rate” from the FY active rate card tier—usually blended staff/expert composite unless models isolate partner rack separately.
- Request Finance’s fully burdened hourly cost for that cohort—loaded salary plus allocable benefits, taxes, hardware amortization, and training—typed as “Fully loaded cost,” not raw wages divided by 2,080.
- Subtract to read “Spread per billable hour”—cash-contribution dollars available before selling, recruiting, and HQ allocations.
- Interpret “Delivery margin %” as contribution margin on invoiced dollars at rack; haircut bill rate when realization averages ninety-two cents on the dollar before presenting board-ready EBITDA bridges.
Common billable rate spread mistakes
- Using raw hourly wage instead of fully loaded cost.
- Using published rack rate when the client actually pays a discounted or blended rate.
- Ignoring utilization, bench time, write-offs, and non-billable delivery work.
- Mixing onshore bill rates with offshore cost rates without modeling the actual staffing mix.
- Comparing employee, contractor, and partner margins without consistent cost treatment.
- Treating delivery margin as net profit before subtracting SG&A, sales, recruiting, management, and taxes.
- Using one blended spread across all roles when senior and junior resources have very different economics.
Billable spread & delivery-margin benchmarks
- Representative management-consulting bill-rate spreads versus burdened cost (North America)
- Healthy boutiques often protect mid-forties to low-sixties percent contribution on rack rates—heavy subcontracting or aggressive discounts compress spread fast
- Loaded-cost completeness benchmarks FP&A audits
- Finance-grade burdens typically include benefits load factor (~25–35%+ on salary), payroll taxes, PTO accrual, and allocated tech—excluding partner draws varies by partnership structure
- Realization drag versus rack-rate math
- Industry trackers cite perennial realization shortfalls—multiply gross spread by historical realization before translating margin percent into cash gross margin
Best use cases
- Growth and performance planning
- Budget and forecast scenario modeling
- Client-facing pre-qualification and education
FAQs
Should loaded cost include recruiter fees amortized per hire?
Only if Finance’s standard burden model spreads recruiting across production hours—some firms keep recruiting in SG&A. Match whichever methodology FP&A already uses for pricing councils.
Why doesn’t delivery margin tie to project gross margin in QuickBooks?
Project profit-and-loss layers subcontractor pass-through, overhead allocation methods, and write-offs differently. This calculator isolates employee rack minus burden—bridge gaps with realization and scope-change rows.
Can I mix offshore blended bill rates with onshore loaded costs?
Only when staffing mixes intentionally blend—otherwise split cohorts or spreads mislead pricing committees optimizing blended offshore/onshore pyramids.
Does partnership profit sharing belong inside loaded cost?
Partnership economics vary—some shops bury draws inside burden, others below EBITDA. Document treatment before comparing percentages firm-to-firm.
How do I calculate spread when the client receives a discounted rate?
Use the realized bill rate, not the rate-card price. If a consultant has a $175 rack rate but the client pays $150 after discount, calculate spread from $150. Otherwise the model overstates delivery margin and hides pricing concessions.
Should utilization be included in the loaded cost per hour?
It depends on your finance model. Some firms load bench time into the cost rate, while others calculate spread on billable hours and then apply utilization separately. Do not double count bench cost by both raising loaded cost and applying a utilization haircut unless FP&A intends that treatment.
How do contractors or subcontractors change billable rate spread?
For contractors, use the contractor's hourly or project-equivalent cost as the loaded cost unless additional management, QA, or platform cost should be allocated. Contractor spread can look healthy at the hour level but compress project margin if oversight and rework are high.
How should I price a blended team with senior and junior roles?
Calculate spread by role first, then weight each role by expected billable hours. A single blended rate can work for proposals, but pricing committees should know whether margin depends on staffing more junior hours than the client expects.
What billable rate do I need to hit a target delivery margin?
Rearrange the margin formula: required bill rate = loaded cost / (1 - target margin). For example, if loaded cost is $92 and target delivery margin is 50%, the required bill rate is $184 per hour before discounts and write-offs.
Why can spread per hour look healthy while the project loses money?
The hourly spread assumes billed hours are realized and scoped correctly. Projects can still lose money through underestimation, unpaid scope creep, write-offs, low utilization, rework, slow approvals, or non-billable project management that never appears in the billable-rate spread.
Glossary
Scenario modeling
Comparing multiple assumption sets to estimate potential outcomes before execution.
Conversion intent
User behavior that indicates readiness to take a commercial action such as signup or purchase.
Related calculators
Related guides
Step-by-step articles on building, embedding, and ranking calculator pages like this one.
Category: Professional services finance & rate-card economicsTopics: Billable rate spread, Loaded labor cost, Contribution margin per hour
Last reviewed: 2026-05-07
Reviewed by: Calclet Growth Team