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FTP OR WATTS PER KILO: WHICH MATTERS MORE?

By Anthony WalshRoadman CyclingUpdated

WHO THIS IS FOR

IS THIS YOU?

The rider who gets dropped on climbs

Your flat-road power is reasonable but hills expose you — W/kg is the number to fix.

The rider unsure which number to train from

You have both metrics and want to know which to use for zone setting, targets, and progress.

THE ROADMAN VIEW

The Roadman view

Here's the thing about raw FTP: it is the number that gets shared on Strava and talked about in the café group. 'What's your FTP?' is a cycling social signal. But the moment the road goes uphill, all of that stops mattering and W/kg takes over entirely. Gravity doesn't care how big your engine is in absolute terms — it only cares how much of it you can bring per kilogram of weight.

For the amateur cyclist training 8–12 hours a week, the split between these two metrics usually points to a clear priority. If you're a bigger rider who excels on the flat, your raw FTP may already be respectable — but your W/kg is held back by weight. If you're a lighter rider who struggles to hold power on flat fast roads, building raw watts is the intervention. Understanding which lever to pull is far more useful than debating which metric matters.

Dan Lorang, who coaches Jan Frodeno and the Bora riders, consistently talks about this balance — that training prescription has to account for the event profile. For most sportive riders, W/kg is the relevant performance number. For time triallists, raw watts matter more. Build your training targets around the metric that governs the riding you actually do.

EXPERT EVIDENCE

WHAT THE EXPERTS SAY

PRACTICAL APPLICATION

DO THIS WEEK

  1. Identify your event profile first

    If your key rides are mostly flat or TT-style, train to raw FTP. If your events have significant climbing (more than 1,000 m per 100 km), W/kg is your primary target.

  2. Audit which lever is most productive

    If you are 10+ kg heavier than your natural racing weight, body composition work likely moves your W/kg faster than an equivalent training block. If you are already lean, build raw FTP.

  3. Set both numbers and track them each 8-week block

    Record FTP in watts and W/kg at each test. Watching both move (or only one moving) tells you whether training and nutrition are both working as intended.

COMMON MISTAKES

WHAT CYCLISTS GET WRONG

  • MISTAKEChasing raw FTP while remaining significantly overweight.

    FIXBody composition work often delivers a bigger W/kg gain than an equivalent training block. Both levers matter — don't ignore the one that's more accessible.

  • MISTAKEUsing W/kg to feel good about modest raw power.

    FIXIf your absolute power is low, W/kg is flattering but limited. You still need to build the engine — especially for flat-road and group-riding speed.

  • MISTAKETraining zones set on raw FTP but riding events where W/kg decides everything.

    FIXZone training off raw FTP is correct. But set your performance goals in W/kg if your target events are hilly.

FAQ

FREQUENTLY ASKED QUESTIONS

At what gradient does W/kg start to matter more than raw watts?
Once a gradient exceeds about 3–4%, gravity starts to dominate and W/kg becomes the key performance predictor. On flat roads at high speed, raw watts and aerodynamics dominate. Most sportives tip the balance toward W/kg.
Should I try to lose weight to improve W/kg?
Only if you have genuine weight to lose without compromising health or fuelling. Losing weight by under-fuelling training will suppress the hard sessions that build power and could actually lower your FTP — a net negative. Weight management should happen around training, not by sabotaging it.
Can I improve W/kg without losing weight?
Yes. Raising your FTP in watts while keeping weight stable raises W/kg directly. This is the most direct path for lean riders who are already well-fuelled.
Is W/kg the right metric for triathlon cycling?
For most triathlons, yes — especially any course with hills. For Ironman-distance racing on flat courses, normalised power and the ability to sustain a specific wattage over 180 km becomes more relevant than peak W/kg.
How do pros compare to club riders in W/kg?
Grand Tour winners typically sustain 6.0–6.5 W/kg at threshold. Strong amateurs sit at 4.0–4.5 W/kg. Club racers at 3.0–4.0 W/kg. The gap to the pros is real and mostly genetic, but closing the gap to the next amateur category is very much achievable.

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