Flight: TIM

Calculate passenger flight emissions with Google's Travel Impact Model (TIM), from flight-level data down to distance-based factors, with an optional contrail impact indicator and airport emissions.

type flightmethodology TIMSupports audit mode

The Travel Impact Model was developed under the aegis of Google and its independent Advisory Committee, whose members come from industry, academia and policy. Drawing on public and licensable datasets, TIM calculates per-seat or per-passenger CO₂e emissions from flight details, aircraft specifics and load factors. Its methodology is validated against real-world data, aims to cover the complete climate impact of aviation, and is available through a freely accessible API.

Sample requests

Send a quote while the traveller is still choosing a flight, then repeat the call with audit set to true once the booking is final. The body is otherwise identical.

{
  "expand": ["items"],
  "items": [{
    "audit": false,
    "type": "flight",
    "methodology": "TIM",
    "origin": "SYD",
    "destination": "MEL",
    "number_of_travelers": 1,
    "booking_class": "economy",
    "airline": "QF",
    "flight_number": "QF0479",
    "aircraft_type": "73H",
    "external_reference": "test",
    "energy_scope": "wtw",
    "logistics_hub": true
  }]
}

audit_for is optional

Pass the ID of an auditable entity when you calculate on behalf of that entity. Otherwise, leave it out.

Defaults

When a field is missing, SQUAKE fills it in before calculating.

Field	Default	Applies when
`booking_class`	economy	No `booking_class` is sent and none can be resolved from `fare_class` and `airline`
`energy_scope`	`wtw`	No `energy_scope` is sent
`logistics_hub`	`false`	No `logistics_hub` is sent

Request fields

typestringrequired

flight

methodologystringrequired

TIM

originstring

IATA/ICAO airport code (MUC), UN/LOCODE for other locations (DEHAM), or latitude and longitude (+40.712,-74.006). Use IATA codes for higher accuracy (Tier 1 or 2). For multi-leg trips, use routing instead.

destinationstring

Same formats as origin. Use IATA codes for higher accuracy (Tier 1 or 2).

routingstring

Hyphen-separated airports for multi-leg itineraries, instead of origin and destination. See Flight: Routing (multi-leg).

departure_datestring

Departure date in YYYY-MM-DD format, aligned with ISO 8601.

flight_numberstring

Include the airline designator, such as "BA115". "115" also works when you send airline separately.

booking_classenum

If you leave it out, sending fare_class and airline is highly recommended so SQUAKE can resolve it. Defaults to economy.

fare_classstring

A single letter such as Y or J. Together with airline, mutually exclusive with booking_class.

airlinestring

IATA designator such as LH; airline names are resolved too. Together with fare_class, mutually exclusive with booking_class.

aircraft_typestring

Aircraft type in IATA or ICAO format.

energy_scopeenum

ttw or wtw. Defaults to wtw.

logistics_hubboolean

Adds airport emissions of 1.71 kg CO₂e per airport, so 3.42 kg CO₂e per item. Use true for the full end-to-end journey per ISO 14083. Defaults to false.

number_of_travelersinteger

Minimum 1. Defaults to 1.

external_referencestring

Your identifier for the item, up to 128 characters, so you can match results to requests. SQUAKE doesn't guarantee the order of items.

sustainable_fuelsboolean

Marks the use of sustainable fuels. This lowers the emissions SQUAKE calculates, but isn't part of the current official frameworks.

carbon_reduction_percentage_of_totalnumber

Share of emissions reduced by sustainable fuel, from 0 to 1. Defaults to 0.

auditboolean

Set to true to create immutable audit records for finalised calculations. Must be enabled for your account.

See every field of POST /v2/calculations in the API reference

Sample response

200 OKapplication/json

{
  "carbon_quantity": 78418,
  "carbon_unit": "gram",
  "items": [{
    "carbon_quantity": 78418,
    "carbon_unit": "gram",
    "external_reference": "test",
    "type": "flight",
    "methodology": "TIM",
    "distance": 706.0,
    "distance_unit": "kilometer",
    "algorithm_specifics": {
      "dataset_type": "google_tim",
      "contrails_impact_bucket": "MODERATE"
    }
  }]
}

Algorithm specifics

The algorithm_specifics object in the response says which dataset produced the figure and how much contrail warming to expect.

`dataset_type`

Value	Meaning
`google_tim`	The standard Travel Impact Model methodology. It uses current and modelled flight data to estimate emissions from flight-specific variables such as aircraft type, route and cabin class. It ensures high accuracy and is aligned with TIM's publicly documented methodology.
`google_tim_fallback`	The input wasn't enough for a precise match, so SQUAKE applied fallback logic to estimate emissions. This can happen when essential data such as the flight number or airline is missing or can't be matched reliably. The result may be less accurate, but is still a reasoned approximation.
`historical_google_tim`	TIM's historical emissions dataset, structured into three tiers by data availability and accuracy. See the tiers below.

Historical tiers

Tier	Dataset	Requires	Use for	Accuracy
1	`TIM past direct flight emissions`	Carrier, flight number, origin, destination, departure date, cabin class	Direct flights only	Highest
2	`Typical flight emissions`	Origin, destination, cabin class	Direct or indirect flights	Medium
3	`Distance-based emission factors`	Distance travelled, cabin class	Direct or indirect flights	Lowest

Tier 1 uses actual scheduled flight data from 2019, covering operating and codeshare flights. It gives the most accurate CO₂e estimate when the full flight details are known.
Tier 2 uses typical emissions based on historical routes between two airports, averaged over several possible flight paths. Useful when flight numbers or dates are unknown.
Tier 3 applies generalised emission factors per kilometre per seat, segmented by cabin class. Use it only when flight routing data is unavailable.

`contrails_impact_bucket`

The estimated climate warming risk from contrails for the flight: "UNSPECIFIED", "NEGLIGIBLE", "MODERATE" or "SEVERE", based on how the contrail impact compares to the flight's fuel burn emissions.

Display only

contrails_impact_bucket isn't converted into CO₂e or combined with fuel emissions.

Bibliography

Travel Impact Model Emissions Data. TIM Team. github.com/google/travel-impact-model

Flight: TIM

Sample requestsCopy Anchor Link

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