Which is the cheapest flight booking site: Google Flights, Skyscanner, Kayak, Momondo or Kiwi.com? We ran the same search on all five for 9 real routes, within about 15 minutes of each other, and compared the cheapest fare each one showed. Here are the results, with a link to each full test.
No single site was always cheapest. Google Flights and Kayak were each cheapest on 6 of the 9 routes, and Skyscanner on 5, with ties counted for each site. On four routes, Google Flights, Kayak and Skyscanner were within 3% of each other. The big gaps were on shorter trips: Google was 26% pricier than Kayak on Singapore to Bali, and Kayak was 14% pricier than Google on Berlin to Madrid. With no clear winner, check your route on all three unless a small saving doesn't matter to you. The one clear loser was Kiwi.com, which ranked last on every route.
Each site is judged on its cheapest fare on one ticket, so the airline has to rebook you if a late flight makes you miss a connection.
✓ cheapest (within 1%) · ≈ within 5% · ✕ more than 5% pricier. Each column shows how that site did across all 9 routes.
| Route |  Google |  Kayak |  Skyscanner |  Kiwi |
|---|---|---|---|---|
| Bali AMS → DPS | ✕ | ✓ | ✓ | ✕ |
| Bangkok AMS → BKK | ✕ | ✓ | ✓ | ✕ |
| New York AMS → JFK | ✓ | ≈ | ≈ | ✕ |
| Las Vegas NYC → LAS | ✓ | ✕ | ✕ | ✕ |
| Bali SIN → DPS | ✕ | ✓ | ✕ | ✕ |
| Madrid BER → MAD | ✓ | ✕ | ✕ | ✕ |
| Tokyo SYD → TYO | ✓ | ✓ | ✓ | ✕ |
| Barcelona DXB → BCN | ✓ | ✓ | ✓ | ✕ |
| Rio KUL → GIG | ✓ | ✓ | ✓ | ✕ |
| Cheapest on | 6/9 | 6/9 | 5/9 | 0/9 |
The only site that showed the Southwest fare that won New York to Las Vegas. Weakest on the Asian routes: 6% over Kayak on Amsterdam to Bali, 9% on Bangkok and 26% on Singapore to Bali. It usually lets you book straight with the airline.
Best on the Asian routes, and the only one of the three that found the S$187 Singapore to Bali fare. Pricier on Berlin to Madrid (14% over Google) and New York to Las Vegas, where it didn't show the Southwest fare. Momondo is owned by the same company and matched it every time.
Tied for cheapest on five routes but never cheapest on its own. It was the priciest of the three on Singapore to Bali, 42% over Kayak, which is why one site isn't enough.
Ranked last on all nine. It's a travel agency, so you book and pay through Kiwi, not the airline. Where Kiwi was cheaper, the trip took much longer, including about 60 hours from Sydney to Tokyo.
Open any route to see all five sites side by side, with the nonstop, one-ticket and self-transfer fares each one showed.
| Route | Cheapest site | Its fare | Nonstop | What stood out | |
|---|---|---|---|---|---|
| 🇳🇱 Amsterdam → 🇮🇩 Bali | Kayak Skyscanner | €803 | No nonstop exists | The cheapest fare on every site was a self-transfer. On the protected Xiamen Air fare, Google was €50 above Kayak. | See the test → |
| 🇳🇱 Amsterdam → 🇹🇭 Bangkok | Kayak Skyscanner | €516 | KLM, from €750 | Kayak and Skyscanner tied on a protected 1-stop. Google's cheapest was €47 more. | See the test → |
| 🇳🇱 Amsterdam → 🇺🇸 New York | Google | €495 | KLM/Delta, from €650 | All three sites were within €13 on the same Aer Lingus 1-stop via Dublin. | See the test → |
| 🇺🇸 New York → 🇺🇸 Las Vegas | Google | $218 | United, from $263 | Google was cheapest because it showed a Southwest fare. Kayak and Skyscanner didn't show it on this search. | See the test → |
| 🇸🇬 Singapore → 🇮🇩 Bali | Kayak | S$187 | Scoot + TransNusa, S$187 | The widest gap in the test: Skyscanner's cheapest nonstop was 42% above Kayak's. | See the test → |
| 🇩🇪 Berlin → 🇪🇸 Madrid | Google | €209 | Iberia, from €588 | Google was cheapest on a Lufthansa 1-stop via Munich. The Iberia nonstop cost nearly three times as much. | See the test → |
| 🇦🇺 Sydney → 🇯🇵 Tokyo | | A$1,068 | Qantas, from A$1,737 | All three sites were within A$3 on a Philippine Airlines 1-stop via Manila. Kiwi's lower fare took about 60 hours. | See the test → |
| 🇦🇪 Dubai → 🇪🇸 Barcelona | | AED 1,241 | Emirates, from AED 3,437 | The closest result: every site showed the same Kuwait Airways fare, one dirham apart. | See the test → |
| 🇲🇾 Kuala Lumpur → 🇧🇷 Rio | | MYR 7,656 | No nonstop exists | The sites were within 1% of each other. Google's cheapest self-transfer had four stops and saved just MYR 93. | See the test → |
Momondo is owned by the same company as Kayak and showed the same fares on every route, so it is counted with Kayak here. Each full test lists Momondo separately. These are July 2026 prices, so expect today\'s fares to differ.
Yes. Kiwi.com is a legitimate online travel agency headquartered in Brno, in the Czech Republic. It sells tickets itself rather than sending you to the airline, so you book and pay through Kiwi, and changes, refunds and cancellations usually go through Kiwi too.
Kiwi is known for joining flights from airlines that don't work together into one itinerary. Those are separate tickets. If a delay makes you miss the next flight, the second airline doesn't have to rebook you. On eligible bookings, the Kiwi.com Guarantee offers its own help, on Kiwi's terms. In our test Kiwi ranked last on all nine routes. Where its price was lower, the trip took far longer, such as a 60-hour Sydney to Tokyo routing.
We test one route at a time. Every site gets the same airports and return dates (8 to 22 September 2026), one adult in economy, the departure city's currency and no VPN. All five searches run within about 15 minutes. We record each site's cheapest nonstop, one-ticket and self-transfer fare, and rank the sites by the cheapest one-ticket fare, because that's the one we'd book. Each result is a snapshot from one day in July 2026, and prices change constantly.