Two numbers define cycling performance more than any other metric: FTP (Functional Threshold Power) and W/kg (watts per kilogram). If you ride with a power meter, race on Zwift, or train with any kind of structure, understanding these numbers is the difference between training with purpose and just clocking kilometres. Here's everything you need to know to test them, understand them, and improve them.
Try it: Use our Cycling Power-to-Weight Calculator to find your W/kg category and see how you compare to performance benchmarks.
What Is FTP?
FTP stands for Functional Threshold Power — the maximum average power output (in watts) you can sustain for approximately one hour. It's the gold standard measure of cycling fitness because it sits at a physiologically meaningful boundary: above FTP you accumulate lactate faster than you can clear it; below FTP you can sustain effort indefinitely (in theory).
FTP is measured in watts, but a 200W FTP means something completely different for a 60kg rider versus a 90kg rider. That's where W/kg comes in — it normalises power output for body weight, allowing meaningful comparison across riders of different sizes.
W/kg = FTP (watts) ÷ Body Weight (kg)Example: A 75kg rider with a 262W FTP has a W/kg of 262 ÷ 75 = 3.49 W/kg
How to Test Your FTP
The 20-Minute FTP Test
The most widely used FTP test is the 20-minute all-out effort. Because a 20-minute maximum effort slightly overestimates true 60-minute power, a correction factor of 95% is applied:
FTP = Average Power over 20 minutes × 0.95Protocol:
- Warm up for 10 minutes at easy pace
- 5-minute hard effort at around 90% max (clears your legs and calibrates your pacing)
- 5-minute easy recovery
- 20-minute all-out effort — start conservatively and build; the classic mistake is going too hard in the first 5 minutes
- Cool down
Example: You average 275W over the 20 minutes. FTP = 275 × 0.95 = 261W
The Ramp Test (Zwift)
The Zwift ramp test is increasingly popular because it's less psychologically brutal than a 20-minute maximal effort. It works by incrementally increasing power by 20W per minute until you can't maintain the target. FTP is estimated as 75% of your best 1-minute power output.
The ramp test is slightly less accurate for very high-volume, aerobically dominant riders (it tends to overestimate their FTP slightly), but it's far more approachable and correlates well for most amateur cyclists.
W/kg Performance Categories (Coggan Scale)
Cycling coach and exercise scientist Andrew Coggan developed the widely used power-based category system. These categories apply to FTP W/kg for male riders; female categories are typically 10–15% lower for the same category.
| Category | W/kg (Men) | W/kg (Women) | Real-World Context |
|---|---|---|---|
| Untrained | <2.0 | <1.5 | Recreational riding, recent beginners |
| Fair (Cat 5) | 2.0–2.4 | 1.5–2.1 | Regular recreational cyclist |
| Moderate (Cat 4) | 2.4–3.0 | 2.1–2.6 | Commuter, casual gran fondo rider |
| Good (Cat 3) | 3.0–3.6 | 2.6–3.1 | Club racing, competitive gran fondo |
| Very Good (Cat 2) | 3.6–4.4 | 3.1–3.7 | State-level amateur racing |
| Excellent (Cat 1) | 4.4–5.1 | 3.7–4.3 | National-level amateur, elite amateur |
| Exceptional | 5.1–5.9 | 4.3–5.0 | Professional cyclist |
| World Class | >6.0 | >5.0 | Tour de France GC contender |
W/kg of Famous Cyclists
To put the numbers in context, here are estimated or reported W/kg values for professional cyclists at their peak:
| Cyclist | Estimated W/kg (FTP) | Achievement |
|---|---|---|
| Miguel Indurain | ~6.0–6.2 | 5× Tour de France winner |
| Lance Armstrong (peak) | ~6.0–6.4 | 7× TdF (stripped) |
| Tadej Pogačar | ~6.2–6.4 | Multiple TdF and Giro winner |
| Jonas Vingegaard | ~6.2–6.5 | 2× TdF winner |
| Cadel Evans | ~5.8–6.0 | 2011 TdF winner (Australian) |
Note: Professional W/kg figures are rarely officially confirmed — these are estimates based on race power data analysis and published interviews. For most amateur riders, reaching 4.0 W/kg puts you in the top 5% of all cyclists globally.
How to Improve Your W/kg: Both Sides of the Equation
W/kg can be improved by raising the numerator (FTP/power) or reducing the denominator (body weight). In practice, the most effective approach combines both.
Improving Power (FTP)
- Threshold intervals: Riding at 95–105% of FTP for sustained intervals (10–20 minutes at a time) is the most time-efficient way to raise FTP for time-crunched riders.
- Polarised training: 80% of your volume at easy aerobic pace (Zone 2), 20% at high intensity. Avoids the "moderate intensity trap" where most amateur cyclists spend too much time.
- Consistency: 8–10 hours of cycling per week, consistently over 6–12 weeks, will improve FTP more than any other single factor.
Managing Weight
- A 5kg weight reduction at 250W FTP moves you from 3.33 W/kg (at 75kg) to 3.57 W/kg (at 70kg) — nearly a full category improvement without any training change
- Weight loss while cycling requires a careful calorie deficit — too large a deficit impairs recovery and power output
- Body composition (lean mass vs fat) matters more than scale weight; aim to preserve muscle while reducing fat
Training Zones Based on FTP
| Zone | % of FTP | Name | Purpose |
|---|---|---|---|
| Z1 | <55% | Active Recovery | Recovery rides, warm-up |
| Z2 | 56–75% | Endurance | Aerobic base, long rides |
| Z3 | 76–90% | Tempo | Sustained moderate-hard effort |
| Z4 | 91–105% | Threshold | FTP development (key zone) |
| Z5 | 106–120% | VO2 Max | Aerobic capacity development |
| Z6 | 121–150% | Anaerobic | Sprint and anaerobic capacity |
Frequently Asked Questions
How often should I retest my FTP?
Every 6–10 weeks during a structured training block. More frequent testing disrupts training and the fatigue from testing itself can skew results. You'll notice FTP improvements through easier perceived exertion at the same wattage — you don't need to constantly test to feel the progress.
Is indoor training (Zwift) as effective as outdoor training?
Yes, for FTP development, indoor training can be equally effective and is often more time-efficient because there are no traffic stops, freewheeling descents, or variable conditions. Elite cyclists routinely complete 60–70% of their training volume indoors. For sportive preparation and race handling skills, outdoor riding is still important.
What W/kg do I need to complete a gran fondo comfortably?
For a gran fondo with significant climbing (2,000–3,000m), a W/kg of 2.8–3.2 will allow you to complete comfortably within time limits and enjoy the event. Below 2.4 W/kg, steep climbs will be a significant challenge. Training specifically for 2–3 months before a major event can realistically move you 0.3–0.5 W/kg.