We ran the exact same search on Google Flights, Skyscanner, Kayak, Momondo and Kiwi.com using the same dates and currency. The tools came out close, and the cheapest fare goes somewhere unexpected. Here's what we found.
The tools came out close. On the Iberia nonstop, Skyscanner was cheapest at €588, with Google just behind at €601 and Kayak up at €687. On the Lufthansa 1-stop through Munich, Google edged it (€209 against €223 to €239). There's no cheap nonstop from Berlin any more, so the real choice is a bare €106 self-transfer routed backwards through London or the sane Lufthansa connection through Munich around €209 to €239. Kiwi.com, a reseller, showed the same flights priced a little higher, so it's last. The honest read: use whichever comparison site you like, just not a reseller. Prices change constantly, so treat this as a snapshot.
Ranked by the cheapest protected connection, the safest fare to book. The badge under each tool shows how you book with it. Every term is explained under the table.
| Rank | Tool | Cheapest direct | Cheapest protected connection | Cheapest self-transfer |
|---|---|---|---|---|
| 1 |  Google Flights Comparison site | €601  Iberia · nonstop 3h 10m | €209  Lufthansa · 1 stop · Munich 4h 45m | €106  Ryanair · via London Stansted ⚠ up to ~6h 40m |
| 2 |  Skyscanner Comparison site | €588 Iberia · nonstop 3h 10m | €223 Lufthansa · 1 stop · Munich 4h 45m | €131 Ryanair · via London Stansted ⚠ up to ~6h 40m |
| 3 |  Kayak Comparison site | €687 Iberia · nonstop 3h 10m | €239 Lufthansa · 1 stop · Munich 4h 45m | €130 Ryanair · via London Stansted ⚠ up to ~6h 40m |
| 4 |  Momondo Comparison site | €687 Iberia · nonstop 3h 10m | €239 Lufthansa · 1 stop · Munich 4h 45m | €130 Ryanair · via London Stansted ⚠ up to ~6h 40m |
| 5 |  Kiwi.com Reseller | €636 Iberia · nonstop 3h 10m | €233 Lufthansa · 1 stop · Munich 4h 45m | €147 Ryanair · via London + Milan ⚠ up to ~20h |
All legs on one ticket, so the airline rebooks you free if a connection is missed. The safest fare to book.
Separate tickets you stitch together (the tool's own label, not ours). Often cheaper, but a missed leg is on you unless a guarantee covers it.
A comparison site shows the fares and sends you to the airline or an agency to pay. A reseller like Kiwi.com takes your payment itself and adds its own fees, so it usually costs a little more.
How close it was: for the same flights, the tools were within a small margin of each other. The Iberia nonstop ran €588 (Skyscanner), €601 (Google), €636 (Kiwi) and €687 (Kayak/Momondo); the Lufthansa 1-stop through Munich was €209 to €239 everywhere. Nobody had a secret fare the others couldn't see. So which comparison site you use barely matters here; what matters is which flight you pick.
A cheap fare isn't always the better deal. When we searched again the prices held, but a self-transfer can strand you: the €106 fare is two separate tickets, so if the first leg is late and you miss the second, that's on you, not the airline. The tools label these "self-transfer" for a reason. On a route where a protected connection is only about €100 more, the cheap headline isn't worth the risk for most people.
Kayak and Momondo are owned by the same company and returned identical fares; we list both because people search for each. Kiwi.com showed the same flights as everyone else, the Iberia nonstop (€636), the Munich 1-stop and the London self-transfer, but it's a reseller: you pay Kiwi rather than the airline, and it priced each option a little higher, so it's ranked last. Prices are live and drift by the hour, so read the pattern, not the exact euro.
That rock-bottom self-transfer is a bare Ryanair ticket: a cabin bag and nothing else. A checked bag is €25 to €45 each way, a seat is extra, and because it's two separate tickets you pay Ryanair's bag fee on each leg. Add a bag both ways and the €106 quickly becomes €180 or more.
The full-service Lufthansa connection at €194 already includes a checked bag and a seat, so once you add luggage to the budget fare the gap between them nearly closes, and the Lufthansa ticket is protected and half the travel time. Add your bags on every option before you compare, not after.