Understanding Change Order Percentage
How we calculate. CO % = change-order dollars ÷ original contract × 100. See our methodology and accuracy policy .
Real-world scenario: A typical Change Order Percentage case uses change-order value 1200000 and original contract 10000000. Enter the same figures below to reproduce the worked path.
What is Change Order Percentage?
A scope-growth signal for owners and GCs. State whether you include pending COs or only executed ones.
- Same currency
- Original contract as the base
- Label executed vs pending
The Formula
Worked Example
Common Use Cases
- Owner controls: scope growth
- GC risk reviews: CO exposure
- Lessons learned: design completeness
Pro Tips
- Separate owner vs contractor-caused
- Watch cumulative vs period COs
- Align with contingency used %
| Scenario | When to use |
|---|---|
| Percent of a number | Finding a part of a whole (tax, tip, score) |
| Percent change | Comparing old vs new values |
Limitations: Change Order Percentage results are educational construction planning aids—not engineering, safety, legal, or cost-estimating advice. Confirm definitions with your project controls, safety, and contract documents. For earned-value SPI/CPI see the Professional hub.
Common mistakes
- Swapping part and whole: The denominator must be the full total, not a subset.
- Rounding too early: Carry extra decimal places through multi-step work before rounding the final percent.
- Mixing percent and decimal forms: Enter rates in the format the calculator labels expect.
The worked example for change order percentage was verified with the calculator form on this page—enter the same values to confirm the result.
When to use this calculator
- Use this page when you have an old value and a new value (or a single percent change rate).
- Use increase by percentage to grow one number by a rate.
- Use decrease by percentage for discounts or shrinkage without a before/after pair.
Still unsure about change order percentage? Start with the quick answer above, then open the linked calculator that matches your wording.
❓ Frequently Asked Questions
How do I use this change order percentage calculator?
For change order percentage, enter the values labeled on the form, then press Calculate. Compare the result to the worked example on this page.
What formula does this page use?
See the quick answer and formula box above for change order percentage—the same percentage calculator expression is applied to your inputs.
What if my result looks wrong?
When checking change order percentage, re-check part vs whole (or rate vs base), rounding, and whether percents were entered as 25 rather than 0.25 when the form expects percents.
Authoritative References
For construction project controls and safety rate concepts, consult: