# How do I know if my pedometer is accurate?

## Perform the step or shake test and compare the numbers

### 1. Perform one or both of the following tests:

#### Step test

1. Set your pedometer to zero.
2. Attach the pedometer to your waistband (in line with the middle of your knee), on either side of your body.
3. Walk 40 steps and count each step as you take it.
4. Compare the number of steps you take to the number your pedometer records.

#### Shake Test

1. Set your pedometer to zero.
2. Hold your pedometer in an upright position as if it were clipped to your waistband. (Your pedometer will not be accurate if it is tilted out of an upright position.)
3. Shake your pedometer 40 times.
4. Compare the number of shakes with what your pedometer records.

## 2. Compare the numbers.

Compare the number of steps your pedometer shows to the number of steps you actually took (or shook). An accurate pedometer has no more than a 10% error:

• 40 steps x 10% (0.10) = 4 steps
• Your pedometer will have no more than a 4-step error in either direction.
##### Example:

If you take 40 steps, your pedometer will count no less than 36 steps and no more than 44 steps for each of the tests.

• 40 + 4 steps = 44 steps
• 40 – 4 steps = 36 steps

The best pedometers have no more than a 5% error. If you take 40 steps, your pedometer will record no less than 38 steps and no more than 42 steps any of these tests.

Take the time to check your pedometer’s accuracy. An inaccurate pedometer won’t do you any good when you’re trying to lose weight; it can trick you into thinking you’re more or less active than you really are.

Sources:
Tudor-Locke, C. E., & Myers, A. M. (2001b). Methodological considerations for researchers and practitioners using pedometers to measure physical (ambulatory) activity. Research Quarterly for Exercise and Sport, 72(1), 1-12.
Vincent, S.D., & Sidman, C.A. (2003). Determining Measurement Error in Digital Pedometers. Measurement in Physical Education and Exercise Science 7 (1): 19–24.