Freelance Scope Changes: Calculate the Extra Work
Calculate extra freelance hours and revised scope. Separate original costs, new work and fixed amounts with a worked example.
Start with what the original estimate included
A request for extra work can change more than the final number. Before entering a new total, write down which hours, quantities and fixed costs were in the first estimate. Then mark what has changed. This gives you a way to explain the difference instead of presenting two unexplained prices.
Suppose a small assignment was estimated at eight hours, with a rate of $70 per hour and $40 in fixed costs. These are fictional inputs for the arithmetic, not suggested freelance rates. The original calculation is 8 × $70 + $40 = $600. No taxes are applied in this example.
The multiplication needs matching units: hours multiplied by dollars per hour produces dollars. OpenStax explains rates and unit prices. For the basic line-item method, see how to build an estimate from quantity and unit price.
Calculate the extra work separately
The revised task needs three additional hours at the same example rate. Calculate those hours on their own: 3 × $70 = $210. Add that change to the original total: $600 + $210 = $810.
| Item | Original | Change | Revised |
|---|---|---|---|
| Hours | 8 | +3 | 11 |
| Labor | $560 | +$210 | $770 |
| Fixed costs | $40 | $0 | $40 |
| Total | $600 | +$210 | $810 |
Check the result another way: 11 × $70 + $40 = $810. Both routes agree. If they do not, compare the inputs before checking the arithmetic again.
A fixed cost does not repeat just because the task changes
The original $40 is already inside the $600. Adding $210 and another $40 would produce $850, which double-counts that same cost. A revised estimate should retain it once unless the revised task creates a separate cost.
For instance, a genuinely new $15 delivery charge would bring the revised total to $825. Label it as new delivery, not another copy of the original fixed costs. When the task repeats next month, reuse the sheet without carrying over stale assumptions: the old rate, quantity and delivery arrangement all need checking.
If the rate also changes, separate the two effects
Imagine a different scenario in which all eleven hours use a new fictional rate of $75. The total becomes 11 × $75 + $40 = $865. Compared with $600, the $265 change consists of $210 for three extra hours at the old rate, plus $55 from applying the $5 rate difference to eleven hours.
That decomposition makes the arithmetic visible. It does not decide which hours should use a changed rate. Establish the applicable inputs first, then calculate them.
Send a revision someone can follow
A short explanation might read: “The revised estimate includes three additional hours at $70 per hour. That adds $210 to the original $600, for a total of $810. The original $40 fixed cost is unchanged.” Include the relevant task or version so the recipient knows which estimate you mean.
Before sending, share the reasoning behind the calculation, including any assumptions that still need confirmation. A clear sum explains a proposed amount; it does not establish customer approval.
Keep the estimate and its context together
Calculator Duo is an iPhone and iPad app in development with labeled calculation sheets, editable rows and sharing as a static image or text. Keep the original inputs and the change together so the next version of an estimate still makes sense. Explore Calculator Duo and join the waitlist for launch updates.
Frequently asked questions
How do I calculate three extra hours?
Multiply the three hours by the applicable rate. At the fictional rate of $70 per hour, the additional amount is 3 × $70 = $210.
Should I add the original fixed cost again?
Not for the same cost already included in the original total. Add a separate cost only when it actually applies to the revision.
How can I check the revised estimate?
Calculate the old total plus the changes, then check it against the full revised quantity × rate plus the applicable fixed costs. Both should use the same assumptions.
Does a calculated scope change mean the customer approved it?
No. The calculation explains an estimate. It does not establish an agreement or customer approval.
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