Sage Earth vs. Dedicated Carbon Accounting Software: When Is £9/Month Enough?

Sage Earth is now available to all Sage Accounting and Sage for Accountants customers in the UK, priced at £9/month + VAT. It sits inside the accounting workflow accountants already use, which means zero onboarding friction.

For many SMEs, the question isn’t whether to measure carbon emissions — it’s whether Sage Earth is enough, or whether they need something more.

This isn’t an attack piece. Sage Earth does specific things well. But the methodology difference between spend-based and activity-based carbon accounting is real, and understanding it matters — especially as ISSA (UK) 5000 raises the quality bar for carbon data from December 2026.

What Sage Earth does well

It’s already there. If your practice runs on Sage Accounting, Sage Earth requires no new software, no new login, no new data integration. It reads your chart of accounts and applies emission factors to spend categories automatically. The activation barrier is close to zero — and for a market where only 9% of SMEs have any formal measurement process, removing friction matters.

The price is right for a first measurement. At £9/month, it’s the lowest-cost entry point in the market. For an SME that has never measured its carbon footprint and needs a starting number, the cost objection disappears.

It produces a number quickly. Sage Earth can generate a carbon estimate from existing accounting data without requiring the user to collect utility bills or fleet mileage. For businesses that just need “a figure” to respond to a basic customer questionnaire, this is fast.

Where spend-based methodology falls short

Sage Earth’s approach is primarily spend-based: it maps financial transactions to emission factors using expenditure categories. Dedicated carbon accounting tools use activity-based methodology: they calculate emissions from physical activity data (kWh of electricity, litres of fuel, km driven) multiplied by specific conversion factors.