Budget at Completion Calculator: EVM Cost Control for Agency Projects

Budget at completion calculator

Open the budget at completion calculator → — enter planned value (PV), earned value (EV), actual cost (AC), budget at completion (BAC) and percent complete, and it returns cost variance (CV), cost performance index (CPI), schedule variance (SV), schedule performance index (SPI), estimate at completion (EAC), estimate to complete (ETC), variance at completion (VAC) and to-complete performance index (TCPI).

Embed the live calculator here, full width, as the first element on the page.

The calculator is free, needs no sign-up, and can be embedded on your own site by adding `?embed=1` to the tool URL inside an iframe.

Budget at completion (BAC) is the total approved budget for all the work in a project — the denominator almost every other earned value number leans on. The formula is: BAC = the sum of the budgets of every planned work package. On a simple fixed-fee agency project, that is just the project's total approved budget. BAC is set once at baseline and does not move when the project overruns; the number that moves is estimate at completion (EAC).

How do I calculate budget at completion?

There are two legitimate routes to BAC, and both are correct — they just suit different kinds of work.

Bottom-up. Break the work into a work breakdown structure (WBS), give every work package a budget, and add them up. Use this when the project has distinct phases you can cost separately, or when you want CPI by phase rather than for the project as a whole.

Top-down. Take the approved contract value or the internal budget you committed to, and treat that as BAC. This is how most agency fixed-fee projects work: the client signed a number, and that number is the budget whether or not anyone itemised it.

A worked example (illustrative numbers)

A brand identity project quoted at $24,000, costed bottom-up:

These figures are illustrative, used to make the arithmetic followable. They are not Wieldy data and not a benchmark.

Should I include client ad spend in my project budget baseline?

No — not if you want the indices to mean anything. If ad spend, print production or stock licensing is billed through to the client at cost, it inflates BAC, EV and AC together and flattens every ratio towards 1.0. A $40,000 media budget running through a $12,000 management fee makes CPI tell you about the client's ad account, not your delivery.

Pick one treatment and stay consistent across every project you compare. The treatment that answers the question agency owners actually ask — are we making money on this? — is to exclude pass-through costs from the baseline entirely and track them separately. More on that in tracking media-buying money flow.

Can budget at completion change during a project?

Only through a formal change: an approved change order, an agreed scope increase, or a deliberate re-baselining of the performance measurement baseline. BAC does not drift upward because the work turned out to be harder. That is the whole point of it. If BAC moves every time you overspend, you have destroyed the comparison the method exists to provide.

The earned value formulas, in the order you actually need them

Every formula below comes from the standard earned value management (EVM) set documented in PMI's PMBOK Guide and in the ANSI/EIA-748 standard for earned value management systems. Wieldy is not certified against either standard; these are the public formulas, applied to agency work.

The running example is the same $24,000 brand identity project, at week six of twelve. Illustrative numbers throughout.

Planned value, earned value and actual cost

Planned value (PV) is the budgeted value of the work that should be done by now. PV = BAC × planned % complete. At week six, the plan said 50% complete: PV = $24,000 × 0.50 = $12,000.

Earned value (EV) is the budgeted value of the work actually finished. EV = BAC × actual % complete. The team assesses real completion at 40%: EV = $24,000 × 0.40 = $9,600.

Actual cost (AC) is what has genuinely been spent: logged hours at loaded cost rate, plus subcontractors, freelancers and production costs. On this project, AC = $12,800.

What good looks like: EV close to PV (on schedule) and AC close to EV (on budget). Here it is neither.

Cost variance and cost performance index (CPI)

Cost variance (CV) = EV − AC = $9,600 − $12,800 = −$3,200. Negative means you have spent more than the work completed was worth.

How is the cost performance index calculated? CPI = EV ÷ AC. Here: $9,600 ÷ $12,800 = 0.75.

Read it as cents on the dollar. CPI of 1.0 means every dollar spent produced a dollar of budgeted value. CPI above 1.0 means you are getting more than a dollar back per dollar spent. CPI of 0.8 means you are getting 80 cents — every dollar of cost is buying 80 cents of the work you priced. At 0.75, a quarter of every dollar spent on this project has produced nothing you can bill for.

Schedule variance and schedule performance index (SPI)

Schedule variance (SV) = EV − PV = $9,600 − $12,000 = −$2,400. Negative means behind plan.

Schedule performance index (SPI) = EV ÷ PV = $9,600 ÷ $12,000 = 0.80. You have delivered 80% of the work the plan expected by now.

Known weakness: SPI drifts back towards 1.0 as a project finishes, because at 100% complete EV equals BAC equals PV — even if you delivered three weeks late. Never read SPI alone in the final stretch. Use a milestone date comparison instead.

Estimate at completion (EAC) — and the four versions of it

What is the difference between BAC and EAC? BAC is the budget you committed to at baseline and it stays fixed. EAC is the forecast of what the project will actually cost by the time it finishes, recalculated as performance data comes in. BAC is the promise; EAC is the projection.

There are four standard EAC formulas and they produce different numbers from the same data. Which EAC formula you should use is a judgement call about why the variance happened:

Quoting an EAC without naming the formula behind it is meaningless. The same project above is forecast at $27,200 or $36,800 depending entirely on which assumption you chose. State the formula every time you report the number.

Estimate to complete (ETC) and variance at completion (VAC)

ETC = EAC − AC — what the remaining work is forecast to cost from here. Using EAC = BAC ÷ CPI: $32,000 − $12,800 = $19,200.

VAC = BAC − EAC — the forecast variance against the original budget. $24,000 − $32,000 = −$8,000.

Sign convention matters: a negative VAC is a forecast overrun. A positive VAC is a forecast underrun. People reverse this constantly in reports, so write the direction in words next to the number.

To-complete performance index (TCPI)

TCPI tells you the cost efficiency the remaining work has to achieve to land on a given target.

• To still hit the original budget: TCPI = (BAC − EV) ÷ (BAC − AC)
• To hit a re-baselined budget: TCPI = (BAC − EV) ÷ (EAC − AC)

In our example, to still finish on the original $24,000: ($24,000 − $9,600) ÷ ($24,000 − $12,800) = $14,400 ÷ $11,200 = 1.29.

Practical reading: you have run at CPI 0.75 for six weeks, and the remaining work has to run at 1.29 to recover. That is a 72% improvement in cost efficiency on work that has so far only got harder. A TCPI materially above 1.0 is not a motivational target. It is a signal to re-scope, re-baseline, or raise a change order.

A full worked example: a $24,000 agency project at week six

All figures illustrative. Twelve-week brand identity project, fixed fee, BAC $24,000. At week six the plan said 50% complete; honest assessment of delivered work is 40%; $12,800 of loaded cost has been logged.

How do I use earned value on a fixed-fee client project?

Here is the part no EVM article written for defence programmes will tell you: on a fixed-fee project this is not a budget problem to escalate to the client. It is a margin problem. The client still pays $24,000. Nothing in the table above changes their invoice. The forecast $8,000 overrun comes out of your gross profit, and nobody outside your agency will ever see it unless you look.

That leaves three levers, and only three:

1. Cut remaining scope back to what was actually sold. The most common cause of a 0.75 CPI in creative work is not slow designers — it is scope that crept in without a change order. Go through the remaining work packages and strike anything that is not in the signed proposal.
2. Raise delivery efficiency. TCPI says what that would take: 1.29, against a run rate of 0.75. Possible on a project that started badly and has since stabilised. Unlikely on one where the difficulty is ahead of you, not behind.
3. Raise a change order for work that was genuinely outside the agreed scope, billed at your standard hourly rate. This is the only lever that moves money rather than redistributing pain — and it only works if you can point at a specific deliverable that was not in the proposal.

What counts as an acceptable overrun, when to re-baseline, and what your out-of-scope rate should be are decisions each agency sets for itself. They depend on your market, your contract terms and your gross margin target. The trade-off is simple: a low tolerance means more change-order conversations and some friction with clients; a high tolerance means margin quietly leaking out of projects nobody flags. Pick your threshold, write it down, and apply it to every project rather than deciding case by case.

Earned value for agencies: what to change before you use it

EVM was built for programmes with cost-reimbursable contracts, dedicated cost accounts and independent verification. Four things have to change before it works on agency P&L.

1. Percent complete is the weak link. Every number downstream of EV depends on it, and self-reported "we're about 70% done" is the single biggest source of fiction in agency EVM. Use fixed-formula credit instead: 0/100 (a work package earns nothing until it is finished, then all of it) for short packages, or 50/50 (half on start, half on completion) for longer ones. Better still for client work, tie credit to client approval rather than internal opinion — a design concept is not 90% done, it is approved or it is not.

2. Actual cost must be cost, not price. If you value an hour at the rate you bill clients, CPI tells you about utilisation, not profit. AC needs the loaded cost rate: salary, plus employer costs, plus the share of overhead that person carries. Those percentages vary by country, employment structure and how you allocate overhead, so work out your own rather than borrowing someone else's. The agency profit calculator walks through the same cost stack at agency level.

3. Pass-through media spend stays outside the baseline. Exclude client ad budgets from BAC, EV and AC. They are not your cost and they are not your value — they are money moving through your bank account. Track them in a separate flow with its own reconciliation, as set out in tracking media-buying money flow.

4. Retainers need a different baseline. A monthly retainer is not one long project. Treat each month as its own BAC equal to that month's retainer fee, and calculate CPI month by month. Over-servicing almost never announces itself — it shows up as CPI sliding from 1.1 to 0.95 to 0.8 across a year, which is exactly the trend you want in front of you before the renewal conversation, not after. How to price your agency retainers covers setting the fee itself.

What is an earned value management system, and do you need one?

An earned value management system (EVMS) is the whole apparatus — the processes, the work breakdown structure, the performance measurement baseline, the change control, the cost accounting and the software — that an organisation uses to run earned value consistently and repeatably. It is not the formulas. The formulas are the easy part.

In the United States, an EVMS is usually measured against ANSI/EIA-748, the national standard that sets out the guidelines a compliant system has to meet. Agencies including the US Department of Defense, NASA and the Department of Energy require ANSI/EIA-748-compliant systems on large contracts, with formal validation reviews. The underlying metric definitions — PV, EV, AC, CPI, SPI, EAC, TCPI — are documented by the Project Management Institute (PMI) in the PMBOK Guide, which is where most people outside government contracting first meet them.

Do small agencies need an EVMS? Almost certainly not. A 15-person agency has no obligation to ANSI/EIA-748 and nothing to gain from compliance. What it needs is three things done consistently:

1. A baselined budget per project, agreed before work starts and not quietly edited afterwards.
2. Time logged against projects at loaded cost, not billing rate.
3. An honest percent-complete method that somebody other than the person doing the work can verify.

Do those three and you can calculate every metric on this page. Skip any one of them and a certified system would produce numbers just as wrong, more expensively.

The realistic progression looks like this: a spreadsheet plus this calculator while you are running a handful of concurrent projects; then software that tracks budget against actual cost automatically, once you are running enough work that the monthly manual recalculation stops happening. The failure mode is not choosing the wrong tool. It is the month where nobody updates the sheet, and then the month after that.

Common mistakes that make earned value numbers lie

• Optimistic percent complete. Inflates EV, hides the overrun until the final two weeks, and turns the whole exercise into a reassurance machine.
• Mixing billing rates and cost rates in AC. Half the hours at cost and half at price produces a CPI that means nothing in either direction.
• Including pass-through client spend in the baseline. Large pass-through amounts drag every index towards 1.0 and mask real delivery variance.
• Quoting EAC without naming the formula. The same project above forecasts at $27,200 or $36,800. Always state which variant produced the number.
• Re-baselining BAC to make the numbers look better. Moving the goalposts erases the only comparison the method provides. Re-baseline when scope genuinely changed, never when performance disappointed.
• Tracking EVM monthly on six-week projects. The feedback arrives after the decision point. Match the measurement interval to the project length — weekly on short work.
• Reading SPI on a nearly finished project. It converges on 1.0 regardless of how late you delivered. Use dates near the end.

Frequently asked questions

What is the formula for budget at completion?

BAC = the sum of the budgeted costs of all planned work packages. On a fixed-fee agency project, BAC is simply the total approved project budget — the number on the signed proposal. It is set at baseline and stays fixed unless scope formally changes through a change order or a deliberate re-baselining.

How is CPI calculated?

Cost performance index (CPI) = earned value ÷ actual cost (EV ÷ AC). If you have earned $9,600 of budgeted value and spent $12,800, CPI = 0.75. Read it as cents of budgeted value per dollar spent. Above 1.0 is under budget, below 1.0 is over, and the gap compounds across the rest of the project.

What does a CPI of 0.85 mean?

A CPI of 0.85 means every dollar you have spent has produced 85 cents of the work you budgeted for — a 15% cost overrun on completed work. Projected forward with EAC = BAC ÷ CPI, a $24,000 project at CPI 0.85 forecasts at roughly $28,235, a forecast overrun of about $4,235. On a fixed fee, that comes out of margin.

What is a good TCPI?

A TCPI at or just below 1.0 is comfortable: the remaining work can be delivered at the efficiency you have already demonstrated. Materially above 1.0 means the rest of the project has to run better than anything you have managed so far. Above roughly 1.1, treat it as a scope or re-baseline decision rather than an effort problem.

Is earned value management worth it for a small team?

The formulas are worth it; a certified EVMS is not. A small agency needs a baselined budget per project, time logged at loaded cost, and a percent-complete method nobody can fudge. With those three, CPI and EAC on a fortnightly cadence will flag a losing project weeks before the invoice does. ANSI/EIA-748 compliance is for government contractors.

What is the difference between earned value and actual cost?

Earned value (EV) is the budgeted value of the work you have actually completed. Actual cost (AC) is the money you have actually spent getting there. EV comes from the baseline; AC comes from your timesheets and supplier invoices. The gap between them — cost variance — is the whole point of the method.

More free agency calculators

Every tool below is free, needs no sign-up and no email, shows its formula with a worked example, and can be embedded on another site by adding `?embed=1` to the tool URL in an iframe.

• Agency profit calculator — works out where gross and net margin actually land once salaries, overhead and pass-through costs are separated properly. Use it when CPI is fine per project but the agency still feels tight.
• Retainer pricing calculator — sets a monthly fee from the hours a retainer really consumes at loaded cost, which is the baseline you need before per-month CPI means anything.
• Tiered sales commission calculator — models tiered and accelerator commission structures so you can see what a plan costs before you announce it.
• All free agency calculators and templates — including the proposal template and invoice generator.

Related reading: the five numbers every agency owner should watch.

Tracking cost performance without rebuilding the spreadsheet every month

The maths on this page is simple. Keeping it current across fifteen live projects is not — which is where most agencies quietly stop. Wieldy tracks budget, logged time at cost and actual spend per client and per project, so the profit picture updates without a monthly manual recalculation, and the built-in AI assistant answers questions about your own live data, such as which projects are over budget this month.

What Wieldy is not: a certified EVMS, or a full accounting ledger. It exports to CSV for your accountant.

You can open the live demo workspace with sample agency data from wieldyapp.com — email only, no account — or start the 7-day free trial with no credit card. Pricing is flat per workspace rather than per user, starting at $59/month for Growth at launch pricing. If you want to talk through moving existing project data, talk to the team.

Written by Ed Kamel, founder of Zerak and Wieldy. Wieldy began as the internal system of the marketing agency he runs, so retainers, sales commissions and media buying are things he manages himself rather than reads about. Published September 2026; reviewed by the Wieldy team.