Cost Variance (CV)
Cost Variance Percentage (CV%) tells you how much you are over or under your budget, expressed as a percentage rather than a raw dollar amount. To understand it, you first need two ideas from Earned Value Management, which is simply a method for measuring how a project is really doing. "Earned Value" (EV) is the value of the work you have actually completed, measured in money (for example, if you've finished a quarter of a $1,000 job, you've earned $250). "Cost Variance" (CV) is that earned value minus what you actually spent — a positive CV means you spent less than the work was worth, and a negative CV means you spent more.
To calculate CV%, you take the Cost Variance, divide it by the Earned Value, and multiply by 100. In plain words: for every dollar of work you completed, what percentage did you save or overspend?
Reading the result is straightforward. A positive CV% means you are under budget — good news. A negative CV% means you are over budget — a warning sign. The bigger the number (in either direction), the more significant the effect. Because it's a percentage, it lets you compare projects of very different sizes fairly, which a raw dollar figure can't do.
A project manager uses CV% in status reports and to spot trends early. A small overspend on a huge project might be fine, but a large negative percentage — say worse than −10% — usually signals it's time to investigate and correct course.
Think of it like checking your grocery receipt as a percentage rather than just the dollars. Overspending by $20 feels very different on a $40 trip (50% over!) than on a $400 trip (5% over). Turning the overspend into a percentage instantly tells you how big a deal it really is.
Imagine you've completed work worth $8,000 (that's your Earned Value, EV), but you actually spent $10,000 to do it. First find the Cost Variance: CV = EV − Actual Cost = $8,000 − $10,000 = −$2,000. Now apply the formula: CV% = CV / EV × 100 = −$2,000 / $8,000 × 100 = −25%. The negative result tells you that you overspent by 25% relative to the value of the work completed — a serious red flag that costs are running well above plan.
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