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About Calasi

What is Calasi?
Our mission is to help you find the best and most fuel efficient flights wherever you choose to fly. We do that by rating the actual comfort, convenience, value, in-flight services and eco efficiency for every commercial flight worldwide. We can also prioritize the factors that are most important to you, so finding the ideal flight is even faster.
How does Calasi work?
Our SmartScore™ is automatically added to the search results of your favorite travel sites. No separate search engine or app is required. Just search for flights as you normally do, and you’ll see our SmartScore™ next to each option. The higher the score, the more value that flight offers for a competitive price. Click on the SmartScore™ for full details, including a recommendation if we see a better choice for you.
What travel sites are compatible with Calasi?
Right now, Calasi is available on every flight search performed with Other sites will be added soon, so check often for an updated list, or sign up for our e-mail updates. You can also visit our Labs page for Calasi products that may be compatible with your favorite travel site.
What does Calasi cost?
Calasi is totally free. We don’t charge a dime, or even
a penny.
What do I need to use Calasi?
No special apps, extensions or plug-ins are required. Calasi is fully integrated with our travel site partners,
so our ratings appear as part of their flight search results.
Is Calasi available in my country?
Wherever our travel site partners offer their service,
you can access Calasi on every search.

How it Works

What flights does Calasi cover?
Calasi offers the latest ratings for every commercial flight in the world, so wherever you’re flying, we can help you make a smarter choice.
How is the SmartScore™ calculated?
Our SmartScore™ is currently based on the following factors: fuel use and carbon emissions per passenger,
in-flight entertainment availability and screen type, seat dimensions (width and pitch), total travel time from initial departure to final destination (including stops and changes), wi-fi availability, and price and value as compared to competing flights. These factors are combined to create an overall score for each flight,
which changes as airlines assign different aircraft, modify their services or upgrade features on a given route.
Will Calasi be adding other categories?
You bet. In the coming months, we plan to expand our SmartScore™ to cover the widest range of features and services possible. Check our site for the latest news, or sign up for our e-mail updates. You can also be the first to know by joining our Calasi Community.
How will Calasi give me personalized scores?
By specifying your preferences for certain airlines, frequent flyer alliances, in-flight services, price ranges and more, we’ll be able to prioritize your ideal flights each time you search. That means the SmartScore™
you receive for certain flights will be different than our standard score, because it’s tailored just for you. To find out when this feature goes live, sign up for our e-mail updates or join our Calasi Community.
Where do you get your scoring data?
We obtain our data from a variety of government agencies and public sources, including the International Civil Aviation Organization (ICAO), International Air Transport Association (IATA), the environmental agencies of several countries, travel resources and industry news. Calasi customers also provide vital feedback about the flights they take. For more information on fuel and CO2 emissions data, please visit the Environment section of this FAQ.
How often do you update the SmartScore™ of different flights?
The SmartScore™ of each flight updated in real time, in step with live changes in price and routing. Reviews from members of our Calasi Community also cause the SmartScore™ to evolve on a regular basis.
Can I submit my own ratings to you?
Absolutely. If you’d like to join our Calasi Community and share your feedback to help us be even more accurate, visit our Community page for details. We always welcome new members, from everywhere in the world.
Is there a chance the services you list won’t be available on a flight?
There is always the possibility that an airline will change the aircraft originally assigned to a given route. When this happens, any number of factors may change as well. Sadly, we have no control over this, but it happens on a very rare basis. If the change is a permanent one, our system will automatically update the score for future flights.
Can I see a demo of how Calasi works?
You know it. Just click here.


Where do you get your fuel and emissions data?
Calasi uses the Great Circle distance method, in conjunction with the 2013 CORINAIR model, which is published by the European Environmental Agency (EEA). We then break down aircraft data to the cabin and seat level, based on seat density of each plane model within a given airline fleet.
How accurate are greenhouse gas emissions estimates?
When calculating fuel and CO2 emissions, we factor in the aircraft model, itinerary, airline, cabin and seat density. This creates a representative and actionable indication, similar to “miles per gallon” or “liters per 100 km” for cars. Soon, we will be enhancing our model with cargo, payload and seasonality data for even greater depth.
What difference does it make when I take a more efficient flight?
Here’s an example. A 5 hour, 30 minute flight from LA to New York can produce as many emissions per economy passenger as about 60 days’ worth of US per capita emissions from electricity usage. Plus, we typically see efficiency variations of 50% on the same flight result page. So, taking a flight with a lower fuel and CO2 rating can make a real difference, and the benefit rises exponentially as more people do the same.
I see a direct flight that produces more emissions than a route with stops. How is this possible?
These cases are rare, but they do occur. If the stopping route uses newer aircraft with more passengers on it, the per-passenger emissions could be less than on a competing nonstop.
Why should I pay more for a fuel efficient flight?
In the majority of cases, you don’t have to pay a higher price to take a more efficient flight. Flights producing lower emissions are often priced exactly the same as others. Also, keep in mind that efficient flights usually give you other advantages, such as direct routes, newer aircraft, wi-fi, etc.


What information does Calasi collect about me?
You’re free to use Calasi without providing any information to us. If you would like to benefit from custom scoring, we will ask you to share your travel preferences, which we’ll use to tailor the SmartScore™ of different flights based on your specific criteria. Saving your preferences for future use, as well as sharing flight reviews and participating in our user community, requires a Calasi account. When you sign up, you can choose what info you provide and who can see it.
Your account is always protected, and set to private by default.
What if I sign up for Calasi updates via e-mail?
If you opt into our e-mail updates, we’ll keep your e-mail address safe, and not share or sell it to anyone. Should we need more info from you, we’ll always ask you first, and clearly explain the reason for our request.
Will a travel site or airline know I’m reviewing flights for Calasi?
Not unless you tell them. We will never share the names or other details about customers kind enough to join our Calasi Community.If you decide to share reviews with us, your name, itineraries, reviews and all other information will be protected.


What does "Calasi" mean?
It’s a variation of "kalasi", which means "gathering" in the South Indian language Telugu. It stands for the good that individuals can achieve when they join together to pursue a goal as a community. That resonates with our beliefs and why we founded Calasi, so we adapted it for our company name.
Do airlines pay you to be featured or rated?
No. The only places where specific airlines may be displayed by choice is in our demos and screenshots. This is because we prefer to show live examples, as these are more useful and relevant for you. The airlines in our examples change all the time, so no one company has a promotional advantage.
Are you attached to any group or organization?
We are an independent company, and don’t partner with, invest in, or allow any outside group to influence our policies. Ensuring we are unbiased is of major importance. We also source all of our data from respected organizations, and closely work with Sustainability Advisors to ensure the integrity of our emissions and fuel data, as well as our own eco-friendly policies.
I own or work for a travel site. Can I partner with Calasi?
Absolutely. We welcome the opportunity to share our ratings with travel sites worldwide. Please send a message to, and we'll be in touch right away.