A project change can add revenue without adding profit. Extra materials, disrupted labour, remobilisation, schedule extensions and administrative time are often overlooked when contractors price additional work.
A change order should document the revised scope, price and schedule before the changed work begins. It should also be based on a complete internal cost calculation rather than a quick guess or an informal percentage.
This guide explains how small contractors can identify change-order costs, calculate a suitable selling price, obtain written approval and protect the project’s expected profit.
Understand What Requires a Change Order
A change order records an agreed modification to the original contract. It may increase or decrease the price, change the scope, extend the schedule or revise another contractual requirement.
Common reasons include:
- Client-requested additions or substitutions
- Unforeseen concealed conditions
- Design or specification revisions
- Code or inspection requirements
- Material unavailability
- Changes requested by an architect or engineer
- Correction of inaccurate client information
- Acceleration or after-hours work
- Deletion of previously included work
- Delays that create additional compensable cost
Not every site instruction automatically entitles the contractor to additional payment. Review the original scope, exclusions and contract procedure before treating work as a change.
Document the reason for the change and identify who has authority to approve it.
Define the Changed Scope Before Pricing
Describe exactly what will be added, removed or modified. A clear scope prevents the change order from creating another disagreement later.
Include:
- Location of the changed work
- Quantities and dimensions
- Materials, products and finishes
- Labour activities
- Demolition, preparation and disposal
- Subcontracted work
- Permits, testing or inspections
- Client-supplied items
- Exclusions and assumptions
- Required drawings or specifications
Compare the change with the original contract and identify any work that has already been priced. Charge only for the net effect of the modification.
If important information is unavailable, state the assumptions used or provide an allowance subject to later adjustment. Do not present an uncertain scope as a fixed and complete price.
Calculate the Direct Cost of the Change
Estimate every direct cost required to complete the changed work.
Include:
- Materials and delivery
- Direct labour hours
- Payroll burden where applicable
- Subcontractor quotations
- Equipment and tool rental
- Demolition and disposal
- Permits, testing and inspections
- Protection and cleanup
- Travel or mobilisation
- Other project-specific expenses
Use current supplier prices and labour rates rather than the rates used when the original project was estimated. A change may occur months later, after costs have increased.
For deleted work, calculate the cost genuinely avoided. Do not credit the full original selling price automatically if some labour, materials, ordering or administrative cost has already been incurred.
Include Disruption and Additional Project Costs
The visible work may represent only part of the change-order cost. A modification can also disrupt work that was already planned or completed.
Consider:
- Work stoppage and restart time
- Remobilisation
- Reordering or returning materials
- Restocking and cancellation charges
- Rework of completed construction
- Additional supervision
- Coordination with subcontractors
- Revised drawings or measurements
- Schedule extension
- Extra site facilities or equipment
- Administrative and documentation time
Include only costs that are reasonably connected to the change and permitted by the contract.
Document how the change affects productivity or sequencing. A short task performed out of sequence may cost more than the same task included in the original workflow.
Recover Overhead on the Changed Work
Additional work uses business resources even when those resources are not listed as direct project expenses. The change-order price should therefore account for an appropriate share of overhead.
Overhead may include:
- Office administration
- Estimating and accounting
- Business insurance
- Software and communication
- Vehicles and facilities
- Management time
- Licensing and professional fees
- General tools and support costs
Use the same consistent overhead-recovery method applied to the original project unless the contract specifies a different method for changes.
Do not assume that adding profit alone will recover overhead. Overhead is a business cost, while profit is the return remaining after all costs have been covered.
Allow for Risk and Uncertainty
Changes are often priced quickly and may involve incomplete information. Include a reasonable allowance for identifiable uncertainty rather than ignoring the risk.
Consider:
- Hidden conditions
- Unconfirmed quantities
- Supplier lead times
- Limited site access
- Compatibility with existing work
- Overtime or accelerated completion
- Inspection requirements
- Additional damage discovered during removal
- Coordination with other contractors
The allowance should reflect the actual risk and should not be used as a substitute for defining the scope.
Where uncertainty is substantial, consider an allowance, unit-rate or time-and-material arrangement if the contract and client permit it. State how the final amount will be calculated and documented.
Calculate the Change-Order Selling Price
After calculating direct cost, disruption cost, overhead and risk allowance, determine the selling price using the business’s chosen pricing method.
If pricing from a target profit margin, use:
Selling price = Total change-order cost ÷ (1 − Target margin)
For example:
- Total change-order cost: $4,000
- Target margin: 25%
- Selling price: $4,000 ÷ 0.75 = $5,333.33
The forecast gross profit is:
$5,333.33 − $4,000 = $1,333.33
A 25% markup would produce a price of only $5,000 and a gross margin of 20%. Confirm whether the business is applying markup or target margin before approving the price.
Price the Schedule Impact
A change may affect the project timeline even when the physical work appears limited.
Evaluate whether it will:
- Extend the completion date
- Delay following activities
- Require resequencing
- Create idle labour or equipment time
- Require overtime or additional shifts
- Delay subcontractors
- Increase supervision or site-running costs
- Affect material delivery dates
- Require remobilisation
State the number of additional days or revised milestone dates when they can be reasonably determined.
If the schedule effect cannot yet be calculated, reserve the right to revise the time and related cost after the necessary information becomes available, subject to the contract and applicable law.
Set the Change-Order Payment Terms
State when the change-order amount will be invoiced and paid. Do not assume that the original payment schedule automatically covers additional work.
Depending on the change and applicable law, payment may be required:
- With written approval
- Before ordering special materials
- When changed work begins
- At a defined progress milestone
- Upon completion of the changed work
- Through revised remaining progress payments
Large or material-intensive changes may require more than one payment stage.
Update the total contract value and payment schedule so the client can see the revised financial position. Avoid postponing all change-order payment until the final invoice unless the business can safely finance the additional cost.
Obtain Written Approval Before Starting
The change order should be approved by authorised representatives of both parties before the changed work begins.
Include:
- Change-order number and date
- Original contract reference
- Description of the change
- Increase or decrease in price
- Revised contract value
- Payment terms
- Schedule impact
- Assumptions and exclusions
- Referenced attachments
- Client and contractor approval
Verbal approval can be difficult to prove and may leave the contractor responsible for costs the client later disputes.
Emergency conditions may require immediate protective work. Follow the emergency and notice provisions in the contract, document the circumstances and obtain written confirmation as soon as reasonably possible.
Track the Change Order Separately
After approval, add the change to the project budget and financial records without losing the original contract information.
Track:
- Approved change-order revenue
- Budgeted change-order cost
- Actual material cost
- Actual labour cost
- Subcontractor and equipment cost
- Amount invoiced
- Amount collected
- Remaining cost
- Forecast profit on the change
- Revised total project profit
Separate tracking shows whether the additional work was priced correctly. A profitable original contract can lose margin when several poorly priced changes are combined with it.
Update the project’s forecast final cost, profit and gross margin whenever a significant change is approved.
Avoid Common Change-Order Pricing Mistakes
Common mistakes include:
- Starting changed work without written approval
- Pricing only materials and direct labour
- Ignoring disruption and remobilisation
- Using outdated supplier or labour rates
- Forgetting overhead recovery
- Applying markup when a target margin was intended
- Crediting deleted work at the full original selling price
- Failing to revise the schedule
- Delaying payment until final completion
- Combining unapproved requests with approved revenue
- Failing to track actual change-order costs
Use a consistent review process before every change order is issued. Small omissions repeated across several changes can remove a significant portion of the project’s expected profit.
Check the Effect on Total Project Profit
A change order should be evaluated both as separate work and as part of the complete project.
After approval, update:
- Total contract value
- Total project budget
- Actual cost to date
- Estimated cost remaining
- Forecast final cost
- Forecast final profit
- Forecast gross margin
- Billing and cash received
A profitable change may improve the project margin, while an underpriced or disruptive change can reduce it.
For guidance on updating the forecast, read How to Track Actual Job Costs and Forecast Contractor Profit.
Use a Connected Change-Order Workflow
Change-order pricing is more reliable when it uses the same cost categories, overhead method and margin calculation as the original project estimate.
The AZELIVO Contractor Bid-to-Profit Toolkit provides four connected Excel tools:
- Job Cost Calculator
- Pricing Calculator
- Estimate Builder
- Profit Tracker
This workflow helps small contractors calculate the cost and selling price of changed work, update the client estimate and payment schedule and monitor the effect on forecast final profit.
Conclusion
A contractor change order should cover the complete financial and operational effect of changed work. Materials and labour are important, but disruption, overhead, risk, payment timing and schedule impact may also affect the true cost.
Define the scope carefully, calculate the internal cost and apply the intended pricing method before presenting the change to the client. Obtain written approval before starting whenever possible.
Finally, track every approved change separately and update the project forecast. Consistent change-order management protects profit and reduces disputes over scope, price and completion dates.