Warehouse & logistics carbon calculator

How this calculation works

A warehouse operation is really three footprints stacked on top of each other, and they land in three different GHG Protocol scopes:

Emissions (kgCO₂e) = activity amount × emission factor, run once per line:

• Electricity (Scope 2). Lighting, conveyors, dock equipment, battery charging for electric forklifts — and, if you run cold-chain, the chillers and blast freezers that dwarf everything else. Enter the kWh from your utility bill.
• Diesel (Scope 1). Fuel burned in equipment you own or control: diesel forklifts, yard trucks, reach stackers, and any delivery vehicles on your own books. Enter the litres from fuel receipts or your fuel card statement.
• Outbound road freight (Scope 3 for most operators). Deliveries performed by subcontracted hauliers, measured in tonne-kilometres — the tonnes of goods moved multiplied by the kilometres they travel.

The calculator applies a published factor to each line and sums the result. Nothing is modelled or interpolated, and the source, year, and licence behind every factor are printed under your result.

The factors behind each line

| Line | Factor | Source | | --- | --- | --- | | Electricity, Singapore (2023 data year) | 0.4085 kgCO₂e/kWh | EMA, Singapore Energy Statistics 2024 | | Electricity, Singapore (2024 data year) | 0.4020 kgCO₂e/kWh | EMA, Singapore Energy Statistics 2025 | | Diesel | 2.686 kgCO₂e/litre | UK DEFRA/DESNZ 2025 | | Road freight | 0.1153 kgCO₂e/tonne-km | UK DEFRA/DESNZ 2025 | | Rail freight (for comparison) | 0.0281 kgCO₂e/tonne-km | UK DEFRA/DESNZ 2025 | | Sea freight (for comparison) | 0.0116 kgCO₂e/tonne-km | UK DEFRA/DESNZ 2025 |

The electricity factor changes with the region selector. Singapore uses the EMA's official grid emission factor, published under the Singapore Open Data Licence. Other grids draw on Ember's yearly electricity data (CC-BY) and should be read as approximate: Malaysia ~0.61, Indonesia ~0.69, Thailand ~0.45, Vietnam ~0.48, the Philippines ~0.61, Japan ~0.46, China ~0.58, India ~0.71, Australia ~0.53, and a world average of ~0.48 kgCO₂e/kWh. The US uses EPA eGRID (0.3712, 2022 data) and the UK uses DEFRA 2025 (0.207). The diesel and freight factors are DEFRA's international defaults and apply whatever region you pick.

A note on cold-chain. If your shed is chilled or frozen, electricity is almost certainly your dominant line — refrigeration runs around the clock in a tropical climate, and a cold store draws far more power than an ambient warehouse of the same size. The calculation itself doesn't change; the kWh figure just gets much bigger, which is exactly why it deserves a real meter reading rather than a guess.

A worked example

Take a mid-sized 3PL operator running an ambient shed with two diesel forklifts and subcontracted last-mile trucking. In one month:

• 8,000 kWh of electricity: 8,000 × 0.4020 = 3,216.0 kgCO₂e
• 600 litres of diesel across the forklifts and a yard truck: 600 × 2.686 = 1,611.6 kgCO₂e
• 5,000 tonne-km of outbound road freight (say 50 tonnes of goods moved an average of 100 km): 5,000 × 0.1153 = 576.5 kgCO₂e

3,216.0 + 1,611.6 + 576.5 = 5,404.1 kgCO₂e ≈ 5.4 tCO₂e for the month

Held steady across a year, that is roughly 64.8 tCO₂e — and the shape of the number is as useful as its size. Electricity is about three-fifths of the total before any refrigeration; add chillers and it dominates outright, which tells you where to look first: the meter, not the trucks. The freight line rewards mode choices too — the same 5,000 tonne-km by rail at 0.0281 kgCO₂e/tonne-km would cut that line by roughly three-quarters, though rail is rarely a realistic option for short-haul regional distribution.

When you only have weight and distance, not a ready-made tonne-km figure

Plenty of delivery manifests and freight invoices state a shipment weight and a route distance separately, with no tonne-km total pre-calculated. Our document-upload pipeline handles this the same way you should by hand: divide the weight by 1,000 to get tonnes, then multiply by the distance.

Take a 3PL delivery run: a customer's invoice states a 3,200 kg pallet shipment moved 850 km by road, with no tonne-km figure printed anywhere on the page.

3,200 kg ÷ 1,000 = 3.2 tonnes 3.2 tonnes × 850 km = 2,720 tonne-km 2,720 tonne-km × 0.1153 kgCO₂e/tonne-km = 313.6 kgCO₂e ≈ 0.31 tCO₂e

That single-shipment figure is small next to the monthly totals in the worked example above, which is exactly the point: freight emissions build up shipment by shipment, and a per-delivery number like this is what a customer questionnaire is often really asking a courier or 3PL to add up across a reporting period.

Common mistakes we see

• Mixing up kilograms and tonnes. Tonne-km needs tonnes, not kilograms — skipping the ÷1,000 step overstates the freight line by exactly 1,000x, an error that's easy to miss because the resulting number still looks plausible on its own.
• Treating a multimodal shipment as one mode. A pallet that travels part by truck and part by container ship isn't purely "road freight" — if you can split the leg distances by mode, do so; the road-only default is a conservative fallback, not a precise answer.
• Forgetting empty backhaul. Tonne-km counts loaded movement. If a significant share of your fleet's mileage runs empty on the return leg, an average tonne-km factor will understate your fuel-based reality.
• Applying the region selector to freight. Only the electricity line changes with the region dropdown above — diesel and freight factors stay fixed to the DEFRA global defaults no matter which country is selected, which surprises operators expecting a Southeast Asia-specific freight factor that DEFRA simply doesn't publish.

What this calculator doesn't cover

Honesty about limitations is part of the method:

• Refrigerant leakage. For cold-chain operators this is the uncomfortable one: fugitive emissions from refrigerant gases are Scope 1 and can be a major line, but they cannot be estimated from a utility bill — you need service records showing top-up quantities and gas types. This calculator does not attempt it.
• Inbound freight. The freight field is outbound only. Goods arriving at your dock are upstream transport and belong in a separate Scope 3 line, usually allocated by your suppliers or your procurement team.
• Subcontractor precision. The tonne-km method is the GHG Protocol's standard fallback when you don't control the trucks, but it assumes average vehicles and average loading. If your haulier can share actual fuel data, a fuel-based calculation is stronger evidence.
• Empty running. Tonne-km counts loaded movement. If your contracts involve significant empty backhaul, an average factor will understate reality.
• LPG or petrol equipment. The diesel field is diesel only. For mixed fleets, run the other fuels through the fleet fuel calculator.
• Well-to-tank emissions. The factors cover combustion and generation, not the supply chains behind the fuel and the grid.

Where this fits in your reporting

These three lines land in three different places on any framework: electricity is Scope 2, forklift and yard-truck diesel is Scope 1, and subcontracted outbound freight is Scope 3 (categories 4 and 9, upstream and downstream transportation). That split doesn't change with the kind of organization behind the warehouse — a logistics operator, a manufacturer's in-house distribution centre, a university's facilities depot, and a public agency's supply hub all apply the same GHG Protocol definitions to the same three meters. Whichever framework eventually asks for the number — ISSB IFRS S2, GRI 305, a customer's questionnaire, or a national reporting code — these three factor-backed lines are the starting inventory, and a tender answer built from them looks very different from a blank cell. Singapore-listed operators can check exact filing dates in our SGX climate reporting deadlines guide.

When you'd rather not type the numbers in by hand, upload your utility bill or fuel statement — extraction is free for up to 3 documents a day (10 with an email address), no signup required, files are auto-deleted after 30 days, and every calculated line shows its factor source and licence. Electricity-only tenants may prefer the simpler business electricity calculator.

Sources

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