budget at completion calculator

Budget at Completion (BAC) Calculator

Use this calculator to estimate your total project budget baseline and quickly review key earned value management indicators.

Planned Direct Costs ($)

Planned Indirect Costs ($)

Contingency Reserve ($)

Management Reserve ($)

Approved Change Orders ($) Use a negative value if scope was removed.

Actual Cost to Date (AC) - Optional ($)

Earned Value to Date (EV) - Optional ($)

Physical % Complete - Optional (%) If provided with EV, calculator shows an implied BAC cross-check: EV / %Complete.

What Is Budget at Completion (BAC)?

Budget at Completion (BAC) is the total approved budget for a project when all planned work is finished. In project controls and earned value management, BAC represents your cost baseline target. It is often established during planning, then adjusted only when approved scope changes are added or removed.

In plain terms: BAC answers the question, "How much should this project cost by the time we are done?"

BAC Formula Used in This Calculator

This calculator uses a practical budgeting formula:

BAC = Direct Costs + Indirect Costs + Contingency Reserve + Management Reserve + Approved Changes

Direct costs: Labor, materials, and equipment directly tied to deliverables.
Indirect costs: Shared overhead, admin support, or facilities allocation.
Contingency reserve: Known-unknown risk funding.
Management reserve: Unknown-unknown risk funding under management control.
Approved changes: Formal scope/cost adjustments to baseline.

How to Use the Calculator

Step 1: Enter your planned cost components

Fill in direct and indirect costs first. Then include reserves and any approved changes. These values create your BAC baseline.

Step 2: Add optional performance data

If you enter AC and EV, the calculator also returns useful earned value metrics:

CPI (Cost Performance Index): EV / AC
CV (Cost Variance): EV - AC
EAC (Estimate at Completion): BAC / CPI
VAC (Variance at Completion): BAC - EAC

Step 3: Review result and forecast risk

A BAC by itself is a baseline. The real value appears when BAC is compared with current spending and earned progress. If your CPI is below 1.0, your projected final cost may exceed BAC.

Quick Example

Assume the following budget plan:

Direct costs: $90,000
Indirect costs: $10,000
Contingency reserve: $5,000
Management reserve: $3,000
Approved changes: $2,000

Your BAC is $110,000.

If AC is $55,000 and EV is $50,000, then CPI = 0.91. If that trend continues, EAC = BAC / CPI = about $121,000, which implies a likely overrun versus the original BAC.

BAC vs EAC vs ETC vs VAC

BAC (Budget at Completion)

Your approved total budget baseline.

EAC (Estimate at Completion)

Your current forecast for what the project will actually cost when complete.

ETC (Estimate to Complete)

How much more money you need from now to finish the remaining work.

VAC (Variance at Completion)

The expected difference between your original BAC and your forecasted EAC.

Common BAC Mistakes to Avoid

Forgetting to update BAC after approved scope changes.
Mixing contingency reserve and management reserve without governance clarity.
Comparing AC to BAC too early without checking percent complete and EV.
Using inconsistent cost categories across work packages.
Ignoring inflation, vendor escalations, or contractual index clauses in long projects.

Best Practices for Better Project Cost Control

Build BAC from a detailed work breakdown structure (WBS).
Time-phase your budget into a cost baseline by period.
Track AC and EV regularly (weekly or biweekly for active projects).
Set CPI thresholds (for example, CPI < 0.95 triggers review).
Reforecast EAC early instead of waiting for late-stage surprises.

Frequently Asked Questions

Is BAC the same as project funding?

Not always. BAC is the approved project cost baseline. Funding may include cash flow timing, portfolio reserves, or organizational financing decisions outside your project baseline.

Can BAC decrease?

Yes. If scope is officially reduced or efficiencies are locked into a rebaselined plan, BAC can be revised downward through formal change control.

What is a good CPI target?

A CPI of 1.00 means on budget. Above 1.00 indicates cost efficiency; below 1.00 indicates overrun pressure. Target thresholds vary by project type and risk profile.

Should I include management reserve inside BAC?

Organizations differ. Many include management reserve above the performance measurement baseline but within total project budget authority. Use your PMO or contract standard consistently.