Engineering invoices depend on contract fee basis, agreed rates, and approved project time. Everhour supports budgeting around that work.
Track billable vs. non-billable time and see your real utilization rate and revenue potential in seconds.
Working hours in the period
Admin, meetings, internal work
Industry average is 75–80%
The calculator gives you the number — Everhour takes it from there.
One click and you're timing. Start a timer, add an entry, edit the details. This is exactly how it feels in Everhour.
Set a budget, assign rates, and get alerted before you're over.
Measurement
Track your budget through time or costs
Every report you need — configured your way, always up to date.
Tracked hours flow straight into a polished invoice — no copy-paste, no manual math.
For engineers, the calculation answers a practical invoice question: which approved project hours are chargeable, at which agreed rate, and what pre-tax amount should appear for the billing period. On a time-basis engagement, the core formula is hours × agreed hourly rate by staff classification, person, or project role. The result is normally stated in U.S. dollars for U.S. billable-hour totals.
The same hour records also support internal checks that are not invoice totals. Architecture and engineering firms often track utilization as direct labor divided by total labor, where direct labor is billable client project work. AIA Best Practices gives 60% to 65% as a general A/E utilization benchmark, and Deltek's 2025 study reported 61.7% for Engineering or E/A firms.
Engineering and land-surveying fees are commonly built from five methods: salary cost times multiplier plus expenses, per diem or hourly rates, cost plus fixed fee, lump sum, or a construction-cost-related method such as a percentage of construction cost. A billable-hours total is directly invoiced only when the agreement bills time by hourly or per diem rates.
For lump-sum, fixed-fee, cost-plus, or percentage-of-construction work, hours still matter, but they answer a different question. They show whether the job is staying inside its labor budget, whether the implied hourly return is acceptable, and whether scope changes need documentation. Do not turn internal hours into client charges unless the contract fee basis allows it.
The clean formula is billable hours × agreed rate, calculated separately for each person or classification before adding the lines. For example, an engineering invoice includes 14 approved billable hours from a senior engineer at $185 per hour, 9 approved hours from a CAD technician at $115 per hour, and 6 approved hours from a project manager at $210 per hour.
The senior engineer line is $2,590, the CAD technician line is $1,035, and the project manager line is $1,260. The pre-tax billable amount is $4,885. If the contract uses all-inclusive classification rates, use those rates. If it uses salary plus negotiated overhead and profit, the invoice support generally needs person, hours, and compensation amount.
There is no profession-wide engineering billing increment such as 0.1 hour or 0.25 hour. Rounding should follow the contract, client requirements, or firm policy. The common mistake is mixing methods inside one invoice: exact timer entries for some people, rounded daily totals for others, and edited spreadsheet values for the final invoice.
Use one rule per engagement and apply it before multiplying by rates. If the contract requires quarter-hour increments, round each entry or daily total according to that rule before calculating the amount. If the contract requires exact approved hours, keep the exact approved total and do not add a minimum billing unit just because another client accepts one.
A one-off calculation is enough when the billing period has a small number of approved entries, one fee basis, one currency, and no dispute about what counts as direct project labor. It is also enough for checking an implied rate on a fixed-fee engineering project or estimating the pre-tax value of pending time before invoice review.
A managed workflow becomes necessary when engineers, designers, CAD staff, and project managers contribute across several budgets or billing methods. Everhour Project Budgeting can track hour-based or money-based budgets, recurring budget periods, threshold email alerts, and budget protection, so project labor can be reviewed before it becomes a billing or overrun problem.
This content is for general information only, may not be fully up to date, and is provided without any warranty or liability.
High Performer
G2
Summer 2026
Best Ease Of Use
Capterra
Summer 2026
Rated in the top time trackers across G2, Capterra, and TrustRadius — with consistent praise for ease of use, integrations, and support.
Add approved hours charged to the project, separate them by the agreed person, classification, or project rate, then multiply each group by its rate. On a time-basis engineering engagement, every hour charged by the consulting engineer's staff working on the project is billed at agreed hourly rates by classification.
Fixed-fee and lump-sum engineering projects are not usually invoiced as hours × rate unless the agreement says so. Hours still matter for internal cost control. Divide the fixed fee by total labor hours to check the implied hourly return, and compare actual direct labor against the project budget.
Use the increment stated in the contract, client billing rules, or firm policy. Engineering fee guidance makes fee basis and hourly rates part of the agreement, but it does not set a universal 0.1-hour, 0.25-hour, or other profession-wide minimum billing increment for engineers.
No. Utilization is an internal A/E management ratio: direct labor divided by total labor. It helps firms understand chargeability and staffing efficiency, but it does not replace the contract's billing method. The invoice total should follow approved project hours, agreed rates, fee basis, expenses, and applicable tax treatment.
No. The United States has no federal VAT/GST and no single national sales-tax rate for billed professional time. Sales tax treatment is state and local, and services can be taxed differently by jurisdiction. Use a jurisdiction-specific tax input only when the engineering service is taxable.
Everhour Project Budgeting tracks hour-based and money-based budgets as engineers log time to projects. Teams can use recurring budget periods, 75%, 90%, 100%, or custom threshold email alerts, and budget protection to stop extra logging after a budget is exceeded.
Everhour Billing & Invoicing turns tracked billable time and expenses into invoices using project or member rates while excluding non-billable work. Invoice lines can be grouped by project, task, person, date, or another available breakdown before export to QuickBooks Online, Xero, or FreshBooks.
Track approved engineering hours against project budgets before invoice review. Everhour connects budgets, billing methods, and alerts so project labor becomes measurable client work.
14-day free trial · No credit card · Cancel anytime
