Hourly Billing Calculator
Calculate professional service invoices and client billing subtotals from hourly time tracking. Converts hours and minutes to exact decimal hours, applies client discount percentages, factors in reimbursable project expenses, and calculates applicable sales tax or VAT.
Agreed hourly billing fee charged to client for professional services
Whole hours worked on the client project or invoice period
Fractional minutes (e.g. 15, 30, 45 mins converted to decimals)
Percentage courtesy discount deducted from professional labour subtotal
Applicable sales tax, VAT, or GST applied to net billable services and expenses
Direct out-of-pocket project costs rebilled to the client (travel, hosting, stock assets)
Final total payable by the client including labor, expenses, discounts, and tax
How to Use This Calculator
- Enter your contracted hourly professional billing fee.
- Enter the logged billable hours and fractional minutes.
- Enter any courtesy client discount percentage (or 0%).
- Enter applicable local sales tax, VAT, or GST percentage.
- Include any reimbursable out-of-pocket project expenses to calculate total invoice due.
Formula & Calculation Methodology
Decimal billable hours equal whole hours plus minutes divided by 60. Multiplying decimal hours by the hourly billing rate yields the labor subtotal. Subtracting client discounts and adding reimbursable project costs gives the taxable subtotal, to which sales tax or VAT is added.
Worked Example
Consultant billing 35 hours and 30 minutes at $85/hr with 5% discount, $120 expenses, and 8% sales tax
Frequently Asked Questions
Why should I convert minutes into decimal hours for invoicing?↓
Clocks run in base-60 (60 minutes per hour), but accounting systems and currency run in base-10. Multiplying 35 hours and 30 minutes as "35.30" produces massive financial errors; converting 30 minutes to 0.50 decimal hours ensures exact multiplication by your billing rate.
Are reimbursable project expenses subject to sales tax?↓
In many jurisdictions, rebilled client expenses (such as printing or software subscriptions) must have sales tax applied if the underlying professional service itself is deemed taxable under local state or provincial tax codes.
What billing increments are standard for professional consulting?↓
Consultants and agencies typically bill in 6-minute (0.10 hr), 15-minute (0.25 hr), or 30-minute (0.50 hr) rounding increments depending on agreement terms.
What limitation should I keep in mind when using this billing calculator?↓
This calculator evaluates single invoice periods and does not track client retainer drawdowns, multi-tier blended agency team billing rates, or recurring late payment interest penalties.
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Open calculator →Source Citation & Disclaimer
Informational tool only; not licensed tax, legal, or financial advice.