Alpe du Zwift FAQ

Four questions, four straight answers. No fluff, no scrolling past 2,000 words about my weekend to find the bit you wanted. If your question is not here, it is probably answered by the calculator at the top of the page shouting a number at you.

How accurate is this calculator?

Accurate enough to be useful, honest enough to admit it is not gospel. Your time is estimated from your w/kg against the historic times of real riders, so it tells you the middle of the pack: roughly half the riders at your w/kg went faster, and half went slower. Treat it as a sensible target rather than a promise — your draft, your warm-up, and how badly your legs decide to hate you on the day all shove the number around. If it tells you 60 minutes and you do 75, the calculator was not wrong; you were just having a 75-minute kind of day.

What is w/kg?

Watts per kilogram — your power output divided by your body weight. It is the number that decides everything on a climb, because gravity does not care how many raw watts you can shove out; it cares how many of those watts have to drag each kilogram of you up the hill. A 90 kg rider at 270 W and a 60 kg rider at 180 W both put out 3.0 w/kg and reach the top of Alpe du Zwift at almost exactly the same time. That is precisely why the calculator asks for your weight and works in w/kg, not watts — and why losing a couple of kilograms can be as good as finding a few extra watts.

How long does Alpe du Zwift take?

The Alpe is 12.2 km of climbing with 1,036 m of gain at an average gradient of 8.5% (and up to 14% on the meaner ramps), so it is never going to be quick. As a rough guide:

• 3.0 w/kg — about 63 minutes.
• 3.2 w/kg — just under the hour, around 60 minutes (the famous sub-60).
• 4.0 w/kg — roughly 49 minutes.

Those come straight out of the same formula the calculator uses, so for your time, just plug your weight and power into the tool above and let it do the maths.

What is the Tron bike?

The "Tron" — officially the Zwift Concept Z1 — is the glowing, wheel-light bike Zwift hands you for sheer stubbornness rather than money. You unlock it by climbing a cumulative 50,000 m. Since Alpe du Zwift serves up 1,036 m a pop, it is one of the fastest ways to grind toward it: about 48 full ascents of the Alpe and the neon is yours. Want the full plan? See the Tron bike guide, which includes a little calculator to count down your remaining metres.