SeaRoutesNav
Sustainability

Maritime CO2 Emissions Calculator

Estimate GLEC-aligned CO2e emissions for sea freight routes using navigable route distance, cargo and vessel data.

GLEC-aligned methodology. ISO 14083:2023 reference. Not accredited, certified, audited or verified.

Calculate route emissions

Select a sea route, cargo amount and vessel type to estimate CO2e emissions.

Checking account state before enabling custom inputs.
Reported bunker fuel (optional, highest quality)

Providing measured bunker consumption switches the calculation to the fuel-based method. Seeded fuel factors are tank-to-wake, so a well-to-wake figure may be reported as TTW with a disclosure warning.

Checking account state...

Route preview

Select a route and calculate emissions to see results.

Calculation methodology

GLEC-aligned methodology. ISO 14083:2023 reference. Not accredited, certified, audited or verified.

Framework
GLEC
ISO alignment
ISO 14083:2023 reference
Method
—
Data quality
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Sea freight carbon calculation

Calculate maritime CO₂ emissions for sea freight

Use navigable sea-route distance, cargo details and vessel information to estimate greenhouse-gas emissions for a maritime shipment. The shipping emissions calculator presents CO₂e results with a GLEC-aligned methodology and an ISO 14083:2023 reference.

Navigable sea route distance

Estimate emissions from a route that follows navigable maritime passages rather than a straight line between ports.

Cargo and vessel inputs

Add shipment quantity, container or cargo details and vessel type so the estimate reflects the planned sea freight movement.

GLEC-aligned CO₂e estimates

Review well-to-wake emissions together with WTT and TTW components, assumptions, warnings and the stated data quality.

How the maritime emissions calculator works

  1. 1Choose the portsSelect the origin and destination ports for the sea freight route.
  2. 2Describe the shipmentEnter cargo quantity, vessel type and optional measured fuel information.
  3. 3Calculate and reviewReview route distance, CO₂e totals, methodology details, assumptions and warnings.

Understand your emissions result

WTW is the total well-to-wake estimate. WTT covers emissions from producing and delivering the vessel fuel, while TTW covers emissions from fuel used onboard. Results depend on the accuracy of the selected route, cargo and vessel inputs.

Use the port distance calculator for a single route, build connected port calls with Voyage Builder, or integrate higher-volume calculations through the Sea Routes API.

SeaRoutesNav provides planning estimates. Results are not accredited, certified, audited or independently verified.

Frequently asked questions

What information is needed to calculate maritime emissions?

Choose origin and destination ports, then enter the cargo quantity and vessel type. Measured fuel consumption can be supplied when available for a fuel-based estimate.

How are sea freight CO₂ emissions calculated?

The calculator combines navigable route distance with cargo and vessel data, or measured bunker fuel when supplied, and applies the available GLEC-aligned emissions factors.

What do WTW, WTT and TTW mean?

WTW is total well-to-wake emissions. WTT covers upstream fuel production and delivery. TTW covers emissions from fuel used onboard the vessel.

Is the emissions estimate certified?

No. The calculator uses GLEC-aligned assumptions and an ISO 14083:2023 reference, but it is not accredited, certified, audited or independently verified.

Can I calculate emissions through the API?

Yes. API access is available for integrating higher-volume maritime emissions calculations into logistics and reporting workflows.