Contract Budget Base (CBB)
EVM Terms
Reviewed by forProject Technology - updated Oct 2026
Quick definition: The Contract Budget Base (CBB) is the total budget authorized under a contract: the Negotiated Contract Cost plus the estimated cost of any Authorized Unpriced Work.
The CBB covers all authorized work, whether or not it has been priced yet. On the budget side, it's made up of the Performance Measurement Baseline (PMB), which holds the budgets for the planned work, plus Management Reserve. Normally the Total Allocated Budget equals the CBB. If it's larger, the difference is the Above Target Budget (ATB), and the project is in an Over Target Baseline (OTB).
What this means for you
The CBB is the top-level number that the project's budgets must add up to. If the budgets and reserves don't match it, something in the budget log is out of balance. It's a key figure checked in reviews such as an Integrated Baseline Review.
Also known as
N/A
Used in
Total Allocated Budget reconciliation
See also
Related job aid
How Contract Price, Cost and Budget Fit Together →FAQ
Is CBB the same as Budget at Completion (BAC)?
No. The CBB includes Management Reserve, while BAC is the budget for the defined work and doesn't include the reserve.
Why are there two ways to calculate CBB?
They're two paths to the same total. One starts from the negotiated contract cost and changes; the other adds up all the budgets and reserves. Comparing them checks that the numbers agree.
Definition maintained by forProject Technology.
© 2026 forProject Technology, Inc.
© 2026 forProject Technology, Inc.
