Percent Spent vs Percent Complete in Construction

<div class="ge-article-wrapper"><nav class="ge-toc" aria-label="Table of contents"><p class="ge-toc-label">In this article</p><ul class="ge-toc-list"><li><a href="#the-formula">The Formula</a></li><li><a href="#the-gap-that-matters">The Gap That Matters</a></li><li><a href="#why-this-confusion-is-so-dangerous">Why This Confusion Is So Dangerous</a></li><li><a href="#worked-example">Worked Example</a></li><li><a href="#common-mistakes">Common Mistakes</a></li><li><a href="#when-percent-spent-is-actually-useful">When Percent Spent Is Actually Useful</a></li><li><a href="#frequently-asked-questions">Frequently Asked Questions</a></li></ul></nav><article class="ge-article-body"><p>Percent spent is the proportion of your total budget you've consumed so far. The formula is AC / BAC x 100. That's it. And it tells you almost nothing about progress. </p><p>Here's the problem: on every project I've worked on, at least one person in a progress meeting has said "we've spent 60% of the budget, so we must be about 60% done." That logic is completely wrong. Percent spent measures budget consumption. <a href="/en/earned-value/definitions/physical-percent-complete">Percent complete</a> measures progress. They're different things, and confusing them has cost more projects more money than any other single misunderstanding in <a href="/en/earned-value">earned value management</a>. </p><p>This term is part of the <a href="/en/earned-value/definitions">earned value definitions glossary</a>. For the core EVM formulas, see the <a href="/en/earned-value/formulas">earned value formulas page</a>. </p><h2 id="the-formula">The Formula</h2><p><strong>Percent Spent = <a href="/en/earned-value/definitions/actual-cost">AC</a> / <a href="/en/earned-value/definitions/budget-at-completion">BAC</a> x 100</strong></p><p>Where: </p><ul><li><strong>AC</strong> = cumulative actual cost of work performed to date</li><li><strong>BAC</strong> = total approved project budget</li></ul><p>If you've spent £5.25M on a £15M project, your percent spent is 35%. Simple arithmetic. But that 35% says nothing about whether you're 35% through the work, 20% through, or 50% through. It only tells you how much of the budget is gone. </p><h2 id="the-gap-that-matters">The Gap That Matters</h2><p>The difference between percent spent and percent complete is where <a href="/en/earned-value/definitions/cost-performance-index">CPI</a> lives. When they diverge, you've got a cost performance problem (or, rarely, a cost performance win). </p><pre class="ge-ascii-diagram ge-anim"> Percent Complete vs Percent Spent (The gap = your CPI problem) 0% 25% 50% 75% 100% |---------|---------|---------|---------| % Complete (EV/BAC): [========|==== ] 28% % Spent (AC/BAC): [========|=========|= ] 35% ↑ GAP = 7 percentage points You've consumed 35% of budget but only delivered 28% of value. CPI = 28% / 35% = 0.80 Every £1 spent delivers only 80p of value. If this trend continues: EAC = £15M / 0.80 = £18.75M Forecast overrun = £3.75M </pre><p>That diagram should be on the wall of every commercial office. When the bars are roughly aligned, you're on track. When percent spent runs ahead of percent complete, you're burning through budget faster than you're delivering value. When percent complete runs ahead, you're outperforming the budget (enjoy it while it lasts). </p><h2 id="why-this-confusion-is-so-dangerous">Why This Confusion Is So Dangerous</h2><p>I've sat in board meetings where a project director presented "35% spent, 35% complete" as evidence the project was on track. Nobody questioned it. The reality? The 35% complete figure was a subjective estimate from the site team. The 35% spent was from the cost report. They happened to match by coincidence, and everyone assumed that meant things were fine. </p><p>Three months later, the same project was reporting 52% spent and 41% complete. By then, the CPI was 0.79 and the forecast overrun was north of £2M. The warning signs were there at month 4. Nobody read them because they were conflating two different metrics. </p><p>The fundamental issue is this: spending money is easy. Delivering value is hard. A project can burn through budget at an alarming rate while making very little physical progress. Material deliveries hit the cost report immediately. Design changes generate abortive costs. Rework eats budget without advancing progress. Percent spent captures all of that. Percent complete doesn't. </p><h2 id="worked-example">Worked Example</h2><span class="ge-worked-label">Worked Example</span><div class="ge-callout ge-anim"><p><strong>Scenario:</strong> A £15M NEC4 Option C highway drainage scheme in South Yorkshire. 18-month programme. At the month 7 progress meeting (July 2025), the commercial manager reviews the numbers.</p><br><p><strong>From the cost report:</strong></p><p>- Cumulative AC = £5,250,000</p><p>- Percent spent = £5.25M / £15M x 100 = <strong>35.0%</strong></p><br><p><strong>From the progress assessment:</strong></p><p>- Physical percent complete (weighted milestones) = <strong>28.0%</strong></p><p>- <a href="/en/earned-value/definitions/earned-value">EV</a> = £15M x 28% = £4,200,000</p><br><p><strong>From the baseline programme:</strong></p><p>- <a href="/en/earned-value/definitions/planned-value">PV</a> at month 7 = £5,100,000 (34% planned complete)</p><br><p><strong>The analysis:</strong></p><br><div class="ge-table-wrap ge-anim"><table class="ge-table"><thead><tr><th>Metric</th><th>Value</th><th>What it tells you</th></tr></thead><tbody><tr><td>Percent spent</td><td>35.0%</td><td>Budget consumption is on track with the plan (34% planned)</td></tr><tr><td>Percent complete</td><td>28.0%</td><td>Physical progress is behind where it should be</td></tr><tr><td>The gap</td><td>7.0 points</td><td>Spending outpacing delivery</td></tr><tr><td>CPI</td><td>0.80</td><td>Every £1 spent delivers 80p of value</td></tr><tr><td>SPI</td><td>0.82</td><td>Progress at 82% of planned rate</td></tr><tr><td>EAC (at current CPI)</td><td>£18,750,000</td><td>Forecast overrun of £3.75M</td></tr></tbody></table></div><br><p><strong>What went wrong:</strong> The earthworks subcontractor hit unexpected clay at 2.8m depth on the northern section. Rates of progress halved while labour and plant costs continued. The cost report captured the spend immediately. The milestone schedule didn't credit any additional progress because the milestone (bulk earthworks complete) hadn't been achieved.</p><br><p><strong>The trap:</strong> If the PM had only looked at percent spent (35%) against the plan (34% should be spent by now), the project would look fine. It's only when you compare percent spent against percent complete that the 7-point gap reveals the problem.</p></div><h2 id="common-mistakes">Common Mistakes</h2><ol><li><strong>Reporting percent spent as percent complete.</strong> This is the big one. I've seen cost reports where the "% Complete" column is actually AC / BAC. That's not progress. That's spend. Label it correctly or people will draw the wrong conclusions.</li><li><strong>Assuming the gap will close naturally.</strong> It won't. A gap between percent spent and percent complete at month 7 almost always widens by month 12. The CPI tends to stabilise or get worse, not improve. On three projects I've tracked, the final CPI was within 0.05 of the CPI at the 30% spent mark. Early indicators matter.</li><li><strong>Ignoring the gap on LOE activities.</strong> Level of effort activities (supervision, site management, <a href="/en/earned-value/definitions/preliminaries">preliminaries</a>) always show percent spent equal to percent complete because EV is claimed on a time basis. This masks real cost issues. Strip out LOE and look at the gap on discrete work packages only.</li><li><strong>Not separating direct and indirect costs.</strong> Percent spent on the whole project includes prelims, insurance, bonds, and other time-related costs. Percent complete is usually measured on direct works only. You're comparing apples with a fruit salad. Separate them.</li></ol><h2 id="when-percent-spent-is-actually-useful">When Percent Spent Is Actually Useful</h2><p>Don't dismiss percent spent entirely. It has legitimate uses: </p><p><strong>Cash flow forecasting.</strong> If you've spent 35% of the budget in 7 of 18 months, you can project the cash draw profile. This matters for funding drawdowns, parent company guarantees, and working capital planning. </p><p><strong>Budget consumption alerts.</strong> A simple rule: if percent spent exceeds the time elapsed percentage by more than 10 points, investigate. On a 12-month project at month 3, you should have spent roughly 25% of the budget (assuming a roughly linear profile). If you've spent 40%, something needs explaining. </p><p><strong>Pain/gain trigger on NEC4 Option C.</strong> The pain/gain mechanism compares total Defined Cost against the target. Percent spent tells you where you are on that journey. If you're 80% spent with 60% of the programme remaining, the pain share conversation is coming. </p><div class="ge-product-note ge-anim"><p><strong>How Gather helps.</strong> Gather's AI reads your site diaries daily and maps progress against your cost-loaded programme, giving you accurate earned value data without manual spreadsheet updates. <a href="https://gatherinsights.com/contact">Book a demo</a> to see it working on a live NEC4 project.</p></div><h2 id="frequently-asked-questions">Frequently Asked Questions</h2><h3>What's the difference between percent spent and <a href="/en/earned-value/definitions/cost-performance-index">CPI</a>?</h3><p>Percent spent (AC/BAC) tells you how much budget you've consumed. CPI (EV/AC) tells you how efficiently you're spending it. CPI is the diagnostic metric. Percent spent is the symptom. A project at 50% spent and 50% complete has a CPI of 1.0 (perfect). A project at 50% spent and 35% complete has a CPI of 0.70 (serious trouble). </p><h3>Can percent spent ever exceed 100%?</h3><p>Yes. If AC exceeds BAC, you've overspent the total budget before the work is finished. On NEC4 Option C, this means the Defined Cost has exceeded the target and the pain share mechanism is in play. Percent spent of 110% means you've spent 10% more than the total approved budget. </p><h3>Should I track percent spent at package level or project level?</h3><p>Both. Project-level percent spent gives the board a headline. Package-level percent spent tells the commercial team where the problems are. On a £25M project, knowing you're 42% spent overall is less useful than knowing the M&amp;E package is 60% spent but only 35% complete while the civils package is tracking perfectly. </p><h3>How do I present percent spent vs percent complete to a client?</h3><p>Side by side, in a table or bar chart, with the gap explicitly stated. Never present one without the other. And always include CPI alongside them. The three numbers together tell the full story. Presenting percent spent alone is misleading. Presenting percent complete alone misses the cost picture. </p></article></div>