Before a business can set a credible reduction target, or produce a Carbon Reduction Plan worth the name, it needs an honest baseline. Here is what that actually involves, using a regional contractor as the working example, not a services business, since that's the shape most readers here actually need.
Standards and boundaries first
A proper assessment is built to the GHG Protocol Corporate Accounting and Reporting Standard, using the UK Government's most recent GHG Conversion Factors. Before any numbers are calculated, the boundaries need setting, an operational control approach covering everything the business has control over, split into Scope 1 direct emissions, Scope 2 purchased energy, and Scope 3 everything else in the value chain.
Where the data actually comes from
Consider a typical regional contractor, roughly 40 staff, a mix of office and site based work, plant and machinery on hire, materials procured project by project. The total comes to around 199 tonnes of CO2 equivalent across the year. The shape of that number is the useful part, not the total itself.
Scope 1 lands at roughly 26 percent, almost entirely diesel burned directly in plant, machinery and generators, not office gas. That's a real, structural difference from a services business, where Scope 1 is usually negligible. A contractor's own fuel use is a genuine, direct part of the footprint, not something buried three tiers down the supply chain. Scope 2 stays small, under 3 percent, office and site electricity combined. Scope 3 still carries the largest share, around 72 percent, but the categories driving it look nothing like a services firm's, materials procurement and plant hire, not flights and homeworking.
The real value of an assessment is not the headline number, it is knowing where to act, and for a contractor that's rarely the office.
Not every number carries the same confidence
The single largest category in this example is purchased construction materials, calculated using a spend based method, a category split specifically because a pound spent on ready-mix concrete and a pound spent on office software carry very different carbon behind them. This is worth being direct about, spend based estimates are the least reliable way to calculate emissions, since they assume a fixed relationship between money spent and carbon produced, which does not hold well across different suppliers. A proper assessment says this plainly rather than presenting every figure with equal confidence. The fix is not a better formula, it is better data, an Environmental Product Declaration from the concrete or steel supplier directly, in place of the spend based estimate.
Hotspots, not just a total
In this example, five categories account for around 89 percent of the entire footprint, purchased construction materials, plant and machinery diesel, waste sent to landfill, staff commuting, and plant and equipment hire, in that order. That's where a reduction plan should focus first, not spread thin across twenty categories with roughly equal effort. Worth noting too, waste sent to landfill outweighs everything else being recycled or composted by a wide margin, in this example alone, that's often the single fastest, cheapest reduction available, before touching material specification or plant fuel at all.