The difference between power meter accuracy and power meter consistency is that accuracy is the power deviation between the rider’s measured and actual power output. Consistency is the ability of the power meter to repeat its measurements without deviating from the base.
You learn why you shouldn’t overlook them when buying a new power meter and if one is more important than the other.
I wrote this article based on in-depth research and consultations with power meter brands and experts. I also show you multiple examples for an easier understanding of the topic.
Let’s dive in!
What Is Power Meter Accuracy?
Power meter accuracy is given in percents and varies between ±0.5-3% on most power meters. It’s the power deviation between the rider’s measured and actual power output.
Check out the following table to see what these power deviations are for different accuracy rates and power outputs.
| Accuracy Rate / Power Output | 250W | 500W | 1000W |
|---|---|---|---|
| 0.5% | 248.8-251.3 | 497.5-502.5 | 502.5-1005 |
| 1% | 247.5-252.5 | 495-505 | 990-1010 |
| 1.5% | 246.3-253.8 | 492.5-507.5 | 985-1015 |
| 2% | 245-255 | 490-510 | 980-1020 |
| 2.5% | 243.8-256.3 | 487.5-512.5 | 975-1025 |
| 3% | 242.5-257.5 | 485-515 | 970-1030 |
What Is Power Meter Consistency?
Power meter consistency is the ability of the power meter to repeat its measurements without deviating from the base. In other words, if you put out the real power of 300W and a power meter measures 303W one ride and 297W during the second ride, the power meter is accurate (±1%) but not consistent.
The following chart shows power meter accuracy vs. power meter consistency. The error bars represent a power meter accuracy rate of 1%.
The dark blue column shows real power. The red column represents readings from an inconsistent power meter, and the blue column readings from a consistent power meter.
Are Cycling Power Meters Accurate?
Yes, cycling power meters are accurate. Their accuracy varies between ±0.5-3%. The vast majority of power meters have an accuracy rate of ±1-1.5%. The least accurate power meters are handlebar power meters (±3%).
Here is a chart based on data samples of more than 70 power meters from various brands.
However, this study showed that the real accuracy might vary. Roadcyclinguk.com did a pretty good job breaking it down. Just keep in mind the study was limited by the number of samples, so take the conclusions with a grain of salt.
Are Cycling Power Meters Consistent?
This is a difficult question, and the answer is: It depends.
The power consistency may vary from power meter to power meter and from brand to brand.
I recommend buying a power meter from established power meter brands that have spent enough money on their product development and quality control.
Power Meter Accuracy and Consistency FAQ
Conclusion
Although the accuracy may seem like one of the most important features of a power meter, you shouldn’t overlook its consistency.
An accurate but inconsistent power meter will provide you with unreliable data that are not comparable in time. This may lead to wrong conclusions in your training and performance.
A consistent but inaccurate power meter, on the other hand, will provide you with data that won’t be comparable with other power sources. So, when you start using a different power meter, your power numbers will differ.
That’s why these two features go in hand. The best power meter should be accurate AND consistent.
