FAR 52.243-1—Changes-Fixed-Price.
Plain-English Summary
FAR 52.243-1, Changes-Fixed-Price, is the standard fixed-price changes clause that gives the Contracting Officer limited authority to direct certain contract changes by written order and requires an equitable adjustment when those changes affect cost or performance time. The clause covers the scope of permissible changes, the specific types of changes allowed under the basic clause and each alternate, the contractor’s duty to continue performance, the process for asserting an adjustment request, the Contracting Officer’s duty to modify the contract, the treatment of obsolete or excess property, and dispute resolution if the parties cannot agree on the adjustment. It also addresses the fact that changes may be made without notice to sureties, if any, and that the 30-day claim period may be varied by agency procedures. The alternates tailor the clause for services, services with supplies, architect-engineer/professional services, transportation, and research and development, reflecting that different contract types need different change authorities. In practice, this clause is the main mechanism for managing within-scope changes on fixed-price contracts without resorting to a new procurement, while preserving the contractor’s right to fair compensation or schedule relief when the Government changes the work.
Key Rules
Written, within-scope changes only
The Contracting Officer may issue written orders changing the contract only within its general scope. A change outside the general scope is not authorized by this clause and may require a different contractual action.
Basic clause change categories
Under the basic clause, the Government may change drawings, designs, or specifications for specially manufactured supplies, method of shipment or packing, and place of delivery. These are the only express change categories in the basic fixed-price supply clause.
Alternate-specific change authority
The alternates expand or tailor the change authority for services, services with supplies, architect-engineer/professional services, transportation, and research and development. Contracting officers must use the correct alternate based on the contract type, because the allowable change subjects differ by alternate.
Equitable adjustment required
If a change increases or decreases the cost of performance or the time required for performance, the Contracting Officer must make an equitable adjustment to price, schedule, or both, and modify the contract. The adjustment applies even if the changed work is not the only work affected.
Contractor must timely assert rights
The contractor must assert its right to an adjustment within 30 days after receiving the written order, unless the Contracting Officer allows a later submission before final payment. This is a procedural requirement, but it is critical to preserving the contractor’s claim for adjustment.
Continue performance while disputing
If the parties cannot agree on the adjustment, the matter becomes a dispute under the Disputes clause, but the contractor must keep performing the contract as changed. The clause prevents work stoppage while the pricing or schedule impact is being resolved.
Property disposition may be directed
If the contractor’s proposal includes costs for property made obsolete or excess by the change, the Contracting Officer may prescribe how that property is to be disposed of. This gives the Government control over disposition issues tied to the change.
Special rule for A-E services
For architect-engineer or other professional services, the alternate prohibits furnishing additional services that will incur extra cost or fee without prior written authorization. This is a stricter control on scope and compensation than the basic clause.
Responsibilities
Contracting Officer
Issue only written, within-scope change orders; select and apply the correct clause or alternate; determine whether a contractor’s adjustment proposal is justified and timely; negotiate and document equitable adjustments; modify the contract for price, schedule, or other affected terms; decide whether to accept a late proposal before final payment; and, when applicable, direct the disposition of obsolete or excess property.
Contractor
Comply with written change orders and continue performance as changed; timely assert the right to an equitable adjustment within 30 days unless a later submission is accepted; support the proposal with cost and schedule impact data; avoid performing additional compensable work without required written authorization in A-E/professional services contracts; and pursue unresolved adjustment issues through the Disputes clause rather than stopping work.
Agency
Use agency procedures to set or vary the 30-day adjustment period where permitted; ensure the proper alternate is prescribed for the contract type; and maintain internal controls so change orders, modifications, and dispute handling are consistent with procurement policy and contract administration requirements.
Sureties
No affirmative action is required under the clause, but they are not entitled to prior notice of the change order under this clause. Their interests may be affected by contract modifications, so they should monitor the contract through normal surety-principal arrangements.
Practical Implications
This clause is the Government’s main tool for making routine within-scope changes on fixed-price contracts without reopening the competition, but it does not authorize unlimited redesign or scope expansion.
Contractors should document cost, labor, material, subcontract, and schedule impacts immediately after receiving a change order; waiting too long can jeopardize the adjustment request even when the change is clearly compensable.
The 30-day assertion period is a common trap: missing it can weaken or bar the contractor’s adjustment request unless the contracting officer accepts a later proposal before final payment.
For architect-engineer and professional services, the prior written authorization requirement is especially important; performing extra work first and asking for payment later is risky.
If the parties disagree on price or time, the contractor must keep working. Refusing to proceed can create a separate default or performance problem even while the adjustment dispute is pending.
Official Regulatory Text
As prescribed in 43.205 (a)(1) , insert the following clause. The 30-day period may be varied according to agency procedures. Changes-Fixed Price (Aug 1987) (a) The Contracting Officer may at any time, by written order, and without notice to the sureties, if any, make changes within the general scope of this contract in any one or more of the following: (1) Drawings, designs, or specifications when the supplies to be furnished are to be specially manufactured for the Government in accordance with the drawings, designs, or specifications. (2) Method of shipment or packing. (3) Place of delivery. (b) If any such change causes an increase or decrease in the cost of, or the time required for, performance of any part of the work under this contract, whether or not changed by the order, the Contracting Officer shall make an equitable adjustment in the contract price, the delivery schedule, or both, and shall modify the contract. (c) The Contractor must assert its right to an adjustment under this clause within 30 days from the date of receipt of the written order. However, if the Contracting Officer decides that the facts justify it, the Contracting Officer may receive and act upon a proposal submitted before final payment of the contract. (d) If the Contractor’s proposal includes the cost of property made obsolete or excess by the change, the Contracting Officer shall have the right to prescribe the manner of the disposition of the property. (e) Failure to agree to any adjustment shall be a dispute under the Disputes clause. However, nothing in this clause shall excuse the Contractor from proceeding with the contract as changed. (End of clause) Alternate I (Apr 1984) . If the requirement is for services, other than architect-engineer or other professional services, and no supplies are to be furnished, substitute the following paragraph (a) for paragraph (a) of the basic clause: (a) The Contracting Officer may at any time, by written order, and without notice to the sureties, if any, make changes within the general scope of this contract in any one or more of the following: (1) Description of services to be performed. (2) Time of performance ( i.e., hours of the day, days of the week, etc.). (3) Place of performance of the services. Alternate II (Apr 1984) . If the requirement is for services (other than architect-engineer services, transportation, or research and development) and supplies are to be furnished, substitute the following paragraph (a) for paragraph (a) of the basic clause: (a) The Contracting Officer may at any time, by written order, and without notice to the sureties, if any, make changes within the general scope of this contract in any one or more of the following: (1) Description of services to be performed. (2) Time of performance ( i.e., hours of the day, days of the week, etc.). (3) Place of performance of the services. (4) Drawings, designs, or specifications when the supplies to be furnished are to be specially manufactured for the Government, in accordance with the drawings, designs, or specifications. (5) Method of shipment or packing of supplies. (6) Place of delivery. Alternate III (Apr 1984) . If the requirement is for architect-engineer or other professional services, substitute the following paragraph (a) for paragraph (a) of the basic clause and add the following paragraph (f): (a) The Contracting Officer may at any time, by written order, and without notice to the sureties, if any, make changes within the general scope of this contract in the services to be performed. (f) No services for which an additional cost or fee will be charged by the Contractor shall be furnished without the prior written authorization of the Contracting Officer. Alternate IV (Apr 1984) . If the requirement is for transportation services, substitute the following paragraph (a) for paragraph (a) of the basic clause: (a) The Contracting Officer may at any time, by written order, and without notice to the sureties, if any, make changes within the general scope of this contract in any one or more of the following: (1) Specifications. (2) Work or services. (3) Place of origin. (4) Place of delivery. (5) Tonnage to be shipped. (6) Amount of Government-furnished property. Alternate V (Apr 1984) . If the requirement is for research and development and it is desired to include the clause, substitute the following paragraphs (a)(1) and (a)(3) and paragraph (b) for paragraphs (a)(1) and (a)(3) and paragraph (b) of the basic clause: (a) *** (1) Drawings, designs, or specifications. (3) Place of inspection, delivery, or acceptance. (b) If any such change causes an increase or decrease in the cost of, or time required for, performing this contract, whether or not changed by the order, the Contracting Officer shall make an equitable adjustment in- (1) The contract price, the time of performance, or both; and (2) Other affected terms of the contract, and shall modify the contract accordingly.