How to use this calculator
- Enter the values from your current project or work period.
- Use realistic costs and time, including unpaid or nonbillable work.
- Select Calculate to update every result.
- Change one assumption at a time to compare scenarios.
#2597 · Salary & HR Tool
Freelance Rush Fee Project Buffer Calculator
Turn a compressed deadline into a concrete safe-start plan. Enter the working hours required, client review delay, contingency percentage, hours you can work per day, and days until delivery. The calculator combines execution time and review latency, adds a risk allowance to the work portion, and compares the result with the available calendar window.
Calculator
Rush deadline bufferFormula
Buffered work = work hours × (1 + contingency). Total elapsed requirement = buffered work + review delay. Available hours = days until delivery × 24.
What the result means
Use the main result as a planning threshold under the assumptions entered. Secondary results explain the time, rate, revenue, or cost components behind that threshold.
Estimates are for planning only. Contract terms, local tax rules, actual expenses, and working conditions may produce different results.
Example calculation
An 18-hour job with 20% contingency needs 21.6 working hours. At 6 hours per day that is 3.6 days; an 8-hour review delay adds 0.33 day, for 3.93 days total.
Tips for better results
- Use recent records instead of ideal estimates.
- Keep billable time separate from total time worked.
- Include project-specific costs before evaluating the result.
- Run a conservative scenario for uncertain workload or demand.
- Recalculate whenever scope, deadlines, fees, or expenses change.
Frequently asked questions
How is contingency time calculated?
The contingency percentage is applied to estimated working hours.
How is client review delay converted to days?
Review hours are divided by 24 because they represent elapsed calendar time.
What does calendar slack mean?
It is the entered deadline minus the estimated buffered work and review time.
Why is workable time limited to 24 hours per day?
A day cannot contain more than 24 workable hours.
Does positive slack guarantee delivery?
No. It only indicates room under the assumptions entered.
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Inputs used in this estimate
| Input | Meaning |
|---|---|
| Estimated working hours | Measured in h |
| Expected client review delay | Measured in h |
| Contingency on work time | Measured in % |
| Workable hours per day | Measured in h/day |
| Days until delivery | Measured in days |