Is site diesel Scope 1 or Scope 2?

Scope 1. Diesel burned in generators, excavators, cranes and pumps that you own or lease is direct combustion under your control. The site's temporary electricity supply is Scope 2. Haulage performed by a third-party trucking contractor is Scope 3 (upstream transportation and distribution).

What is a tonne-km and how do I estimate it?

One tonne of goods moved one kilometre. A 20-tonne load of rebar hauled 50 km is 1,000 tonne-km. Estimate it from delivery orders: load weight times trip distance, summed across deliveries. If you only know total tonnes and a typical yard-to-site distance, tonnes times that distance is a reasonable first pass.

Does this include the embodied carbon of concrete and steel?

No. The carbon emitted making cement, steel and other materials is deliberately out of scope — measuring it properly needs quantity take-offs and environmental product declarations, not a three-field calculator. For most buildings it is the largest part of the total footprint, so treat this tool's result as the site-activity slice, not the whole project.

Should I enter figures per project or per year?

Per project. Enter the totals for the whole job, or for a single claim period if you want to track progressively. If a report asks for annual figures, apportion the project totals to the months that fall in each financial year.

Which emission factors does this calculator use?

Diesel (2.686 kgCO2e/litre) and road freight (0.1153 kgCO2e/tonne-km) come from the UK DEFRA/DESNZ 2025 conversion factors, published under the Open Government Licence. Electricity uses the grid factor for the region you select — for Singapore, EMA's published factor of 0.4020 kgCO2e/kWh (2024 data year, SES 2025). Activity dated within 2024 resolves to the prior 0.4085 kgCO2e/kWh figure instead. The exact factor, source and licence are shown under every result.

Free calculator

Construction project carbon calculator

Estimate a construction project's site emissions — diesel plant, temporary power, and materials haulage — using published, openly licensed factors.

Country / regionSite diesel (litres)Generators, excavators, cranes — from fuel delivery invoices.Site electricity (kWh)Materials haulage (tonne-km)

Prefer to skip the typing? Upload the bill instead — the numbers get read for you, three documents a day free.

How this calculation works

Most carbon calculators assume a year of operations. Construction doesn't work that way — a project has a start date, an end date, and a stack of invoices in between. This calculator is built for per-project accounting: enter the totals for the whole job (or for a single claim period, if you want to track as you go) and you get one figure you can attach to that project.

It sums three activity lines:

Emissions (kgCO₂e) = diesel (litres) × diesel factor + electricity (kWh) × grid factor + haulage (tonne-km) × road freight factor

Site diesel is everything combusted on site in plant you own or lease — generators, excavators, cranes, hoists, dewatering pumps. That is Scope 1: direct emissions from fuel you burned. Take the litres from your fuel delivery invoices; they are the cleanest evidence you will have.
Site electricity is the temporary power supply metered to the site. That is Scope 2, and the right factor depends entirely on which grid the site sits on — hence the country selector above.
Materials haulage is trucking to site, measured in tonne-kilometres: one tonne moved one kilometre. A 20-tonne load of rebar hauled 50 km from the supplier's yard is 1,000 tonne-km. If a third-party contractor does the trucking — which is the normal arrangement — this line is Scope 3 (upstream transportation), not Scope 1. It still belongs in the project number; it just carries a different label in a formal report.

The factors behind the three fields

| Input | Factor | Source & licence | | --- | --- | --- | | Site diesel | 2.686 kgCO₂e/litre | UK DEFRA/DESNZ 2025 conversion factors (Open Government Licence v3.0) | | Site electricity, Singapore (2024 data year) | 0.4020 kgCO₂e/kWh | EMA, Singapore Energy Statistics 2025 (Singapore Open Data Licence) | | Site electricity, Singapore (2023 data year) | 0.4085 kgCO₂e/kWh | EMA, Singapore Energy Statistics 2024 (Singapore Open Data Licence) | | Road haulage | 0.1153 kgCO₂e/tonne-km | UK DEFRA/DESNZ 2025 conversion factors (Open Government Licence v3.0) |

Diesel and road freight use the UK Government's DEFRA/DESNZ 2025 conversion factors — the most widely used open-licence factor set for fuels and transport. Diesel combustion chemistry doesn't change at a border, so these serve as sensible international defaults wherever your site is.

Electricity is the opposite: it depends on the local generation mix. Singapore's EMA-published grid factor is 0.4020 kgCO₂e/kWh for the 2024 data year (SES 2025) — the value this calculator currently applies for Singapore. Activity dated within 2024 resolves to the prior 0.4085 kgCO₂e/kWh figure. Switch the region and the calculator swaps in the matching grid factor — approximately 0.61 for Malaysia, 0.68 for Indonesia, 0.55 for Thailand and 0.71 for India (Ember yearly electricity data, verified 2023 country values), 0.207 for the UK (DEFRA 2025) and 0.3712 for the US (EPA eGRID 2022). Whichever region you pick, the exact factor, source, data year and licence are printed under your result, so the provenance travels with the number.

A worked example

A contractor closes out a 14-month light-industrial build. From the project file:

Diesel: fuel delivery invoices total 12,000 litres across the genset and tracked plant.
Electricity: the temporary supply metered 18,000 kWh over the build (Singapore site, 2024-data-year factor).
Haulage: delivery orders for precast, rebar and M&E plant work out to roughly 25,000 tonne-km.

12,000 L × 2.686 kgCO₂e/L = 32,232 kgCO₂e 18,000 kWh × 0.4020 kgCO₂e/kWh = 7,236 kgCO₂e 25,000 t-km × 0.1153 kgCO₂e/t-km = 2,883 kgCO₂e (rounded)

Project total ≈ 42,351 kgCO₂e ≈ 42.4 tCO₂e

Note the shape of that answer: diesel is roughly three-quarters of the site-activity total. That is typical, and it is useful — if you only have time to chase one data trail per project, chase the fuel invoices first.

What this calculator doesn't cover

Being clear about the boundary is part of the method:

Embodied carbon of materials. The concrete, steel, aluminium and glass in the building carry emissions from cement calcination and steelmaking that occurred long before the first truck arrived — and for a typical building, that embodied carbon dwarfs everything burned and metered on site. Measuring it honestly requires quantity take-offs and environmental product declarations (EPDs) per material, which a three-field calculator cannot do — so we leave it out rather than dress up a guess as a number. Treat this tool's result as the site-activity slice of the project, not its whole footprint.
Subcontractors' own plant fuel. If a subcontractor fuels their own excavator, those litres never hit your invoices. Ask for their fuel records or note the gap explicitly in your workings.
Sea and air freight of imported materials. The haulage field applies a road factor. Sea freight is far less carbon-intensive per tonne-km (0.0116 versus 0.1153 by road, DEFRA 2025), so running a shipping leg through this field would badly overstate it. Keep the road field for road legs only.
Worker transport, site waste and water. Real categories, usually much smaller numbers, and better handled by dedicated tools. Company vehicles running to and from site belong in the fleet fuel calculator.

Where this fits in your reporting

Site diesel is Scope 1, site electricity is Scope 2, and subcontracted materials haulage is Scope 3 (upstream transportation, category 4). That mapping holds whether the entity closing out the project is a private contractor, a developer's own capital-works team, a school building a new block, or a public agency's infrastructure programme — the GHG Protocol doesn't distinguish by ownership. Whatever framework eventually wants the figure — ISSB IFRS S2, GRI 305, a client questionnaire, or a national code — a per-project fuel-power-haulage number built from invoices is a defensible starting inventory, and property developers and main contractors are already among the heaviest users of supplier questionnaires asking for exactly this. Singapore-listed contractors can check exact filing dates in our SGX climate reporting deadlines guide.

If the site also has a permanent office account, track that monthly with the business electricity calculator. And when you'd rather not type totals in at all, upload the fuel invoices and power bills — the free tier takes 3 documents a day with no signup (10 with an email address), files are auto-deleted after 30 days, and every extracted figure shows the factor and licence applied to it.

Sources

UK Government (DEFRA/DESNZ), Greenhouse gas reporting: conversion factors 2025 (Open Government Licence v3.0): gov.uk/government/collections/government-conversion-factors-for-company-reporting
Energy Market Authority, Singapore Energy Statistics — grid emission factor tables (Singapore Open Data Licence): ema.gov.sg/resources/singapore-energy-statistics
Ember, Yearly Electricity Data — country grid intensities (CC-BY): ember-energy.org
US EPA, eGRID — US grid emission factors (public domain): epa.gov/egrid
GHG Protocol, Corporate Value Chain (Scope 3) Standard — upstream transportation and fuel categories: ghgprotocol.org

Frequently asked questions

Is site diesel Scope 1 or Scope 2?: Scope 1. Diesel burned in generators, excavators, cranes and pumps that you own or lease is direct combustion under your control. The site's temporary electricity supply is Scope 2. Haulage performed by a third-party trucking contractor is Scope 3 (upstream transportation and distribution).
What is a tonne-km and how do I estimate it?: One tonne of goods moved one kilometre. A 20-tonne load of rebar hauled 50 km is 1,000 tonne-km. Estimate it from delivery orders: load weight times trip distance, summed across deliveries. If you only know total tonnes and a typical yard-to-site distance, tonnes times that distance is a reasonable first pass.
Does this include the embodied carbon of concrete and steel?: No. The carbon emitted making cement, steel and other materials is deliberately out of scope — measuring it properly needs quantity take-offs and environmental product declarations, not a three-field calculator. For most buildings it is the largest part of the total footprint, so treat this tool's result as the site-activity slice, not the whole project.
Should I enter figures per project or per year?: Per project. Enter the totals for the whole job, or for a single claim period if you want to track progressively. If a report asks for annual figures, apportion the project totals to the months that fall in each financial year.
Which emission factors does this calculator use?: Diesel (2.686 kgCO2e/litre) and road freight (0.1153 kgCO2e/tonne-km) come from the UK DEFRA/DESNZ 2025 conversion factors, published under the Open Government Licence. Electricity uses the grid factor for the region you select — for Singapore, EMA's published factor of 0.4020 kgCO2e/kWh (2024 data year, SES 2025). Activity dated within 2024 resolves to the prior 0.4085 kgCO2e/kWh figure instead. The exact factor, source and licence are shown under every result.