Change-order math shows how much approved additions move the total beyond the original scope.

Revised total: $2,900.00
Change order tax: $0.00
Change vs original: 16.0%

Original amount
$2,500.00
Change order amount
$400.00
Tax %
0.0%

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Change Order Calculator

Use this when approved extra work changes the original project amount.

This calculator helps sellers, freelancers, and contractors show how much approved additions changed the original scope and final price.

How to use this page

Start with your best current estimate, adjust the inputs until the result feels realistic, and use the related tools below when you want to pressure-test price, profit, or payout from another angle.

Add a change order to an original quote and see the revised project total.

Use the calculator with the examples below to test ideas quickly and come back to the same setup later.

Worked examples

Start from a realistic scenario

Each example opens the same calculator with shareable URL state.

Approved project change

A small approved addition layered onto the original quote.

$2,900.00revised total

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FAQ

Quick answers

Short answers for the questions that usually come up first.

Why show the change as a share of the original amount?

Because it makes the size of the scope change easier to judge than dollars alone.

Can I leave tax at zero?

Yes. The page still works as a clean change-order calculator even when no tax is added.