From this site

One project, every trade

Each calculator adds its lines to a single estimate — consolidated BOM, schedule and cash-flow included.

Open My Project →

Change Order Cost Calculator

Calculate the total cost of a mid-project change order, including markup and admin fees.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-25 · v1.0.0

Market
Imperial · sales tax

Total change order cost

2400 $ (total change order cost)

High confidence
Markup amount
300 $

With the figures above, the total change order cost comes to 2400 $ (total change order cost). Note that additional work cost and administrative fee sit at the edge of the range this calculator was checked against, so treat the output as indicative rather than settled. This is calculated for United States and cites IRC 2024. Building in another market? Change the selector above so the units and code reference follow.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • Total change order cost = additional work cost x (1 + markup percent / 100) + administrative fee

Your workspace

Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.

Frequently asked questions

Why do change orders often cost more than the same work quoted upfront?
Mid-project changes disrupt sequencing, may require re-ordering materials on short notice, and add coordination overhead that wasn't priced into the original bid — hence the added markup and admin fee on top of raw cost.
Should every scope change go through a formal change order?
For anything beyond trivial, yes — a written change order protects both parties by documenting the added scope, cost, and any schedule impact before the work proceeds, avoiding disputes later.
Can a change order ever reduce the contract price?
Yes — change orders can also remove scope (a deductive change order), which should credit the client for the removed work's cost, though administrative fees sometimes still apply for the paperwork involved.