A walking speed of 3.8 mph is well above average and firmly in the “brisk” category. Most adults walk casually at around 2.5 to 3.0 mph, so if you’re consistently hitting 3.8, you’re walking faster than the large majority of people and getting a solid workout in the process.
Where 3.8 MPH Falls on the Scale
The CDC classifies anything at or above 2.5 mph as brisk walking, which qualifies as moderate-intensity exercise. At 3.8 mph, you’re not just clearing that bar, you’re well past it. The Compendium of Physical Activities, a database researchers use to categorize exercise intensity, assigns a value of 4.8 METs to walking between 3.5 and 3.9 mph on a firm, level surface. For context, anything between 3.0 and 6.0 METs counts as moderate-intensity exercise, and anything above 6.0 is vigorous. At 4.8, you’re in the upper half of moderate intensity, approaching the boundary of a vigorous workout.
In practical terms, 3.8 mph translates to roughly a 15:47 minute-per-mile pace. If you use a fitness tracker or treadmill, that number is useful for checking whether you’re actually maintaining the speed you think you are.
How It Compares to the Average Person
The average casual walking speed for most adults falls between 2.5 and 3.1 mph. Older adults (over 65) tend to average even lower, around 2.1 mph, though some walk as fast as 3.1 mph on flat terrain. Even among people who walk specifically for exercise, research from Harvard Health found that a “brisk” pace typically lands around 2.7 mph, equivalent to about 100 steps per minute.
So at 3.8 mph, you’re walking significantly faster than what most researchers define as brisk. Some people at this speed are on the edge of breaking into a jog, depending on their height and leg length. If you can sustain 3.8 mph for 30 minutes or more, your cardiovascular fitness is above average for a walker.
Health Benefits at This Speed
Walking faster doesn’t just burn more calories per minute. It’s independently linked to living longer, regardless of how much total time you spend walking. A large study using UK Biobank data found that brisk walkers had a 21% lower risk of dying from any cause (men) and a 27% lower risk (women) compared to slow walkers. The reductions were even more dramatic for specific conditions: brisk-paced men had a 38% lower risk of dying from cardiovascular disease, and both men and women had roughly a 72% lower risk of dying from chronic obstructive pulmonary disease.
The key finding was that walking pace mattered independently of total walking time. Someone who walks fast for 20 minutes may get more protective benefit than someone who strolls for an hour. At 3.8 mph, you’re comfortably in the pace range associated with these benefits.
Treadmill vs. Outdoor Walking
If you’re hitting 3.8 mph on a treadmill, the effort is slightly less than walking at the same speed outdoors. Research comparing energy expenditure between treadmill and outdoor exercise has consistently found that outdoor movement requires more oxygen, largely because of wind resistance and subtle variations in terrain. The treadmill belt also assists your stride slightly by pulling your foot backward.
A well-known 1996 study found that running outside on flat ground was roughly equivalent to treadmill exercise at a 1% incline. The same principle applies to walking. If you want your treadmill session at 3.8 mph to match what you’d experience on a sidewalk, setting the grade to 1% closes the gap. Without that adjustment, your outdoor 3.8 mph walk is a harder workout than the same number on the treadmill display.
Can You Push Higher?
For most people, walking speed tops out somewhere between 4.0 and 4.5 mph before the body naturally wants to transition into a run. The exact threshold depends on leg length, hip flexibility, and how efficient your walking gait is. Some race walkers maintain speeds above 5 mph, but that requires a specific technique most people don’t use casually.
If 3.8 mph feels comfortable and you want more intensity without running, adding incline is more effective than trying to push to 4.0+ mph. A 3.8 mph walk at even a 3% to 5% grade increases energy expenditure substantially and builds more lower-body strength, particularly in the glutes and calves. This is often a better progression than chasing a faster flat speed, which can feel awkward as you approach the walk-run transition point.
At 3.8 mph on flat ground, you’re already in a strong position. It’s faster than most people walk for exercise, intense enough to count as solid moderate-intensity cardio, and squarely in the range associated with meaningful reductions in disease risk and mortality.