The Complete Guide to FTP Testing: Comparing the 20-Minute Test, 8-Minute Test, and Ramp Test

Introduction

FTP (Functional Threshold Power) is the core metric in power-based training, representing the highest average power you can sustain for approximately one hour. All training zone calculations and TSS accumulation are based on FTP. However, “testing FTP” itself requires nuance—different testing protocols can yield results that differ by 5–15%, and if your FTP is set incorrectly, the intensity of your entire training plan will be off.

This article will provide an in-depth comparison of three mainstream testing methods to help you choose the one that best suits you.

Three Mainstream Testing Methods

20-Minute Test (×0.95)

This is the most widely used method, originating from Andy Coggan’s research. The protocol is as follows:

1. 10-minute warm-up
2. 5-minute all-out effort (to deplete muscle phosphocreatine and avoid affecting the subsequent test)
3. 5-minute easy recovery
4. 20-minute all-out test, maintaining as steady an output as possible
5. Multiply the average power by 0.95 to obtain FTP

The logic behind the 0.95 coefficient is that a 20-minute all-out output is slightly higher than the true 60-minute FTP, hence the discount. This method is more accurate for aerobic endurance athletes (time trialists, climbers) because they are better able to sustain a steady output.

8-Minute Test (×0.90)

Two 8-minute all-out efforts are averaged, then multiplied by 0.90. This requires less effort than the 20-minute test and is suitable for the following scenarios:

• Beginners who are not yet accustomed to pacing at high intensity for extended periods
• When fatigue has already accumulated before test day, making a 20-minute effort unfeasible
• Sprint-type riders with strong anaerobic capacity (short-duration output better reflects their characteristics)

The drawback is that the coefficient is debatable; riders with strong anaerobic capacity may produce an 8-minute output far exceeding their true FTP, leading to overestimation.

Ramp Test

A testing method that has gained great popularity on platforms such as Zwift and TrainerRoad in recent years. Power increases by a fixed wattage (usually 15–20W) every minute until exhaustion, and FTP is calculated as the highest 1-minute power from the final completed minute × 0.75.

Advantages:

• Short total duration (approximately 20 minutes including warm-up)
• No pacing strategy required—stop at exhaustion
• Low psychological pressure, suitable for beginners

Disadvantages:

• It leans more toward measuring VO2max power and may underestimate FTP for purely aerobic endurance athletes
• The 0.75 coefficient is not universally applicable

Comparison of the Three Methods

Practical Advice for Taiwanese Riders

• First test: It is recommended to use the Ramp Test, as it carries the lowest psychological pressure and provides a reasonable starting baseline.
• Advanced trainees: Use the 20-minute test, as its results best reflect true “power-endurance” capability.
• Pre-test preparation: Avoid high-intensity training for 2 days before the test, ensure adequate sleep and nutrition on test day, and choose a familiar route or use an indoor trainer to eliminate interference from traffic lights and traffic.
• Common issues in Taiwan: When performing a 20-minute test on climbing routes such as Yangmingshan or Wuling, descents following climbs can disrupt output stability; it is recommended to conduct the test indoors instead.

Practical Recommendations

1. Retest FTP every 6–12 weeks, especially at the transition points between phases of your training plan.
2. FTP test results are for reference only; if training zones consistently feel “too easy” or “too hard,” adjust proactively.
3. Consistency of testing conditions is important: whether indoors or outdoors, temperature and fueling methods can affect results, so try to keep conditions similar for each test.
4. If the difference between two test results exceeds 10%, first investigate whether there are issues such as insufficient sleep, illness, or overtraining.

Conclusion

There is no absolute “correct answer” in FTP testing. The key is to find a method that suits your physiological characteristics and training habits, and to consistently track progress using the same method. The absolute value of the number holds no ranking significance; being accountable for your own progress is the true spirit of power-based training.

Related Reading

• Comparison of FTP Testing Methods: Differences Between 20-Minute, Ramp Test, and 8-Minute Tests
• Full Comparison of FTP Testing Methods: Accuracy and Applicability of 20-Minute, 8-Minute, and Ramp Tests
• Comprehensive Comparison of FTP Testing Methods: Accuracy and Applicable Scenarios of 20-Minute Test vs Ramp Test
• Comparison of FTP Testing Methods: 20-Minute Test vs Ramp Test vs 60-Minute Test