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Unapproved Extra Work Cost Calculator

Use this calculator to estimate how much revenue and administrative time may be exposed when extra work starts before the customer gives written approval.

Direct answer

The estimate is based only on your inputs. It is not a guarantee of loss or recovery, and it is not legal, accounting, or tax advice.

No signup required
Uses integer cents and percentage basis points
Does not send your calculator inputs to analytics
Feeds into the free Change Order Generator

Published by ChangeProof. Last updated: June 23, 2026.

Estimate the exposure

Enter your assumptions, then choose Calculate exposure. Results are not saved and are not sent to analytics.

Extra-work volume

Estimate how many scope changes or extras come up in a year.

Approval and dispute assumptions

Use your own assumptions. Do not enter customer details or project names.

Administrative cost

Estimate owner or admin time spent sorting out disputed extra work.

Optional revenue context

Used only to show exposure as a percentage. Leave blank if you do not want that comparison.

Methodology

What unapproved extra work costs a contractor

Unapproved extra work can create two kinds of exposure: the value that may be written off or discounted if the customer disputes it, and the owner/admin time spent resolving the dispute.

ResultFormula
Annual request countextra-work requests per month x active months per year
Annual extra-work valueannual request count x average request value
Value started before approvalannual extra-work value x percentage started before written approval
Expected disputed request countannual request count x percentage started before approval x percentage later disputed
Estimated disputed valuevalue started before approval x percentage later disputed
Estimated unrecovered valueestimated disputed value x average percentage written off or discounted
Estimated administration costexpected disputed request count x admin minutes per dispute / 60 x owner/admin hourly cost
Combined annual exposureestimated unrecovered value + estimated administration cost

Why extra work becomes disputed

Extra work often becomes disputed when the contractor and customer remember the conversation differently. The risk grows when the changed scope, price, and schedule impact are not documented before the work begins.

  • Verbal authorization
  • Scope ambiguity
  • Price not documented
  • Schedule impact not documented
  • Scattered text messages

Worked fictional example

This example uses fictional numbers to show the math. It is not an industry benchmark and should not be treated as a prediction.

Extra-work requests per month12
Average request value$1,250.00
Started before written approval40%
Later disputed25%
Average write-off or discount50%
Administrative time per dispute90 minutes
Owner/admin hourly cost$60.00
Active months12
Annual extra-work request count144
Annual extra-work value$180,000.00
Value started before approval$72,000.00
Estimated disputed request count14.4
Estimated disputed value$18,000.00
Estimated write-offs or discounts$9,000.00
Estimated dispute-administration cost$1,296.00
Combined estimated annual exposure$10,296.00
Monthly exposure equivalent$858.00

What written extra-work approval should document

A written approval should make the customer response clear before the work begins. The correct form and process depend on the contract and applicable law.

  • Changed scope
  • Price
  • Schedule impact
  • Customer response
  • Date and time

Limitations

Contracts differ, local laws differ, and emergency-work procedures differ. This calculator estimates exposure based on your assumptions; it does not determine legal entitlement or guarantee collection.

FAQs

What is unapproved extra work?

Unapproved extra work is added construction work that starts before the customer gives written approval for the changed scope, price, or schedule impact.

How do contractors estimate revenue at risk?

A simple estimate starts with annual extra-work volume, the value of that work, the percentage started before approval, the percentage later disputed, and the percentage written off or discounted.

What percentage of disputed work should I enter?

Use your own job history or a conservative assumption. Do not enter an industry benchmark unless you have a reliable source for your business.

What administrative costs should I include?

Include owner, office, or project-management time spent finding messages, explaining scope, revising paperwork, negotiating discounts, and following up on disputed extra work.

Does written approval guarantee payment?

No. The answer depends on the contract and applicable law. ChangeProof is a workflow and documentation tool, not legal advice.

Can I charge for extra work without a signed change order?

The answer depends on the contract and applicable law. ChangeProof is a workflow and documentation tool, not legal advice.

How can I document extra work before starting?

Document the changed scope, price, schedule impact, customer response, and date/time before the work begins. The approval method should follow the applicable contract.

Unapproved Extra Work Cost Calculator for Contractors | ChangeProof | ChangeProof