Estimate project credits
Net credits for biochar, improved cookstoves, safe water, borehole rehabilitation, forestry and ARR, and solar, with every deduction itemised.
Carbon project calculators that show their working.
Estimate credits for biochar, cookstove, forestry, solar and water projects, or size an organisation's footprint. Every formula, factor and deduction is on the page. When a project needs a client-ready document, unlock a branded report from £29.
Free to use. No card needed. Built for carbon project developers, consultants and sustainability teams.
Biochar example · 1,000 kg wet wood chipDefault assumptions
Dry mass850 kg
Biochar produced238 kg
Gross CO₂e0.611 t
Net estimated0.467 t
- Wet biomass1,000 kg
- After drying850 kg
- Biochar238 kg
- Net CO₂e467 kg
Methodology references
- Gold Standard
- Verra VCS
- Puro.earth
- ISO 14068-1
- ICROA
- IPCC
Run a real calculator right here
These are the same tools as the app. Adjust any input and the result updates. Save your work with a free account when you want to come back to it.
Live biochar calculator with default screening assumptions.
Tools for the three jobs that come up most
Start with the question you have. Each calculator links its method and sources, so the numbers can be checked by a colleague, a funder or a verifier.
Test whether a project stacks up
Revenue over the crediting period, validation and verification costs, and which standard and methodology fit your project.
Size an organisation's footprint
Scope 1, 2 and 3 screening estimates using UK DESNZ factors, a net zero pathway, and the offset cost of residual emissions.
A report you can hand to a client or funder
When the numbers are ready, unlock a branded PDF for that project. It carries your logo and sets out:
- the project summary and headline result
- every input and assumption, with its source
- the full calculation, deduction by deduction
- scenario comparisons, risks and next steps
Edit the project later and re-export it without paying again.
You can see where every number comes from
No black boxes. Change an input and you see its effect straight away, which matters when someone asks you to justify a figure.
- Sourced factors
- Emission factors and conversion ratios come from IPCC guidance, UK DESNZ conversion factors and published methodology documents, and each calculator lists its sources.
- Permanence and deductions shown
- Biochar permanence, leakage, buffers and process emissions appear as separate lines rather than being folded into one number.
- Cautious defaults
- Starting values sit at the conservative end of published ranges, so a first result is not flattering by accident.
// Biochar carbon chain
dry_mass = wet_biomass × (1 − moisture)
biochar = dry_mass × yield
carbon = biochar × carbon_content
gross_co2e = carbon × 3.667 // 44/12
net_co2e = gross_co2e
− process − logistics
− permanence − haircutFree to calculate. Pay when a report matters.
Every calculator is free. Buy a report only when a project needs a branded, client-ready output.
Free
£0
- All 14 calculators
- On-screen results and working
- Free account to save projects
- No card required
One project report
£29 one-off
- Branded PDF for one project
- Inputs, assumptions and sources
- Re-export after edits, permanently
Three project reports
£69 one-off
- Three report credits
- Use them as projects are ready
- Permanent re-export for each
Unlimited reports
£199 for 12 months
- Unlimited report unlocks for 12 months
- Projects unlocked keep re-export
- Renewal terms shown at checkout
Need live website embeds, team set-up or help configuring reports? Talk to us.
Why not just use a spreadsheet?
A spreadsheet is fine for a private scratch model. The Carbon Workbench is for when the same calculation needs to be reused, shared, exported or put in front of a client.
| Feature | The Carbon Workbench | Spreadsheet | Enterprise GHG software |
|---|---|---|---|
| Carbon project calculators | Included | Build yourself | Usually footprint only |
| Sources and working shown | Included | If you add them | Varies |
| Saved, repeatable scenarios | Included | Easy to overwrite | Included |
| Branded PDF reports | From £29 | Manual formatting | Often limited |
| Website embeds | Available | Not practical | Rare |
| Time to first result | Minutes | Hours or days | Weeks |
| Starting price | £0 | £0 plus upkeep | Often £500+ a month |
Questions people ask
How accurate are the calculations?
They use published factors and methodology guidance, including IPCC guidance, UK DESNZ conversion factors and Gold Standard, Verra and Puro.earth documents, with conservative defaults and every step shown. They are screening estimates: suitable for feasibility work, proposals and funder conversations. Credit issuance needs independent validation and verification.
Can I use these numbers in a Gold Standard or Verra submission?
Use them to plan a project and check your working. A formal submission needs the registry's approved methodology tools, monitoring data and verification by an accredited body. Reports list every input and deduction, which makes that handover easier.
What's free?
All 14 calculators, the on-screen results and working, and a free account to save scenarios and projects. You pay only when you want to export a branded report.
How do report purchases work?
One report (£29) or three reports (£69) add credits to your account. Using a credit permanently unlocks that project, so you can re-export it after edits. Unlimited reports gives report unlocks for 12 months, with renewal terms shown at checkout.
What does a report include?
A project summary and headline result, inputs and assumptions with sources, the full calculation deduction by deduction, scenario comparisons, risks and recommendations, all with your branding. You can download a sample report.
Can I put the calculators on my own website?
Yes. You can preview every embed for free on the embeds page. Live embeds with your branding and lead routing run on an embed workspace that we set up with you.
How do I know which methodology to use?
Use the free Methodology Selector. Choose your project type, scale, region and priority, and it ranks suitable standards and methodologies with a plain-English explanation.
How are emission factors kept up to date?
We review emission factors against UK DESNZ updates, IPCC guidance and methodology changes from the relevant standards, and note the source and year in each calculator.
Try a calculator now. It's free.
No card needed. Pay only when a project needs a professional report.