A change order and a variation order describe the same thing — a formal change to the contracted scope, price, or time — under different contract families. "Change order" is the American term, used in AIA and ConsensusDocs contracts. "Variation" is the term in FIDIC and JCT contracts, which govern most international and UK work. The mechanics, however, are not identical, and the differences decide whether you can refuse to start.
The short comparison
| Change order (US / AIA) | Variation (FIDIC / JCT) | |
|---|---|---|
| Where you meet it | United States, AIA and ConsensusDocs contracts | International FIDIC work, UK JCT contracts |
| Who issues it | Agreed between owner, architect and contractor | Instructed by the Engineer (FIDIC) or Contract Administrator (JCT) |
| Is it bilateral? | Yes — it is an agreement both sides sign | No — it is an instruction you are bound to carry out |
| Can you decline to start? | Generally yes, until it is signed | Generally no — you must proceed and be valued afterwards |
| When is the price fixed? | Usually before signing | Usually after, under the contract's valuation rules |
| How is it priced? | Negotiated lump sum, unit prices, or time and materials | The contract's own rates first; new rates only if the work differs in character |
Why the terminology splits
The vocabulary follows the contract form, not the country you are standing in. A US subcontractor working a project in Dubai or Doha will almost certainly be under a FIDIC form and will be issued variations, not change orders. A British contractor working for a US developer may find themselves signing change orders.
- AIA A201 and ConsensusDocs — "change order", plus the separate "construction change directive" for proceeding before price agreement
- FIDIC Red, Yellow and Silver Books — "Variation", handled under Clause 13, Variations and Adjustments, in both the 1999 and 2017 editions
- JCT Standard Building Contract — "Variation", introduced by an architect's or contract administrator's instruction
- NEC3 and NEC4 — neither term. NEC uses "compensation event", which covers a wider set of circumstances than a variation does
The difference that actually matters
If you take one thing from this comparison, take this: under a US change order you generally negotiate, then work. Under a FIDIC variation you generally work, then get valued.
FIDIC Clause 13 obliges the contractor to execute an instructed variation. You cannot hold the site hostage until a number is agreed. The protection is not the right to refuse — it is the valuation machinery in the contract and, above all, your own records of what the work actually cost.
The US contract does have a close equivalent to the FIDIC position: the construction change directive, which orders you to proceed before price and time are settled. The difference is that a directive is the exception in US practice, while under FIDIC it is the normal path.
How each one gets priced
Valuation is the other real divergence. A US change order is typically priced by the contractor and negotiated — you submit a breakdown of labor, material, equipment and markup, and the parties agree a number.
A FIDIC or JCT variation is valued by rule rather than by negotiation. Where the contract is measured — the FIDIC Red Book, or a JCT contract with quantities — the starting point is the rates already in the bill of quantities, and new rates apply only where the varied work differs in character, conditions, or quantity from what was priced. Lump-sum forms, including the FIDIC Yellow and Silver Books, have no bill of quantities to measure against, so valuation works from the contract's own pricing schedules instead. Either way the commercial consequence is the same: if your original rates were tight, a large variation priced at those same rates can enlarge a loss rather than recover one.
- Check whether the varied work genuinely differs in character — that is the gateway to new rates
- Record actual resource usage from day one, not from the day the dispute starts
- Watch the notice periods, which are frequently shorter and enforced more strictly than in US practice
Notice is stricter than most people expect
Both systems have notice requirements, but international forms tend to treat them as conditions precedent — miss the deadline and the entitlement can be lost outright, regardless of the merits. FIDIC's claim provisions are the well-known example. Diarise the deadline the day the instruction arrives, not the day you get around to pricing it.
Working across both
The documentation habits are identical even when the contract language is not: written direction with a name and a date, daily records of labor and material, photographs of the condition before work starts, and a clear statement of schedule impact. That evidence is what a valuation, a claim, or a negotiation is built from in either system.
For the US-side mechanics in detail, see what a change order is and what it must contain, and a worked example with real numbers.
ScopeConductor numbers your change orders automatically, attaches field photos as evidence, sends them for signature and follows up until you get an answer.
See how it works