What is the 12-3-30 workout?
The 12-3-30 workout is a treadmill routine with three numbers: set the incline to 12%, the speed to 3 miles per hour and walk for 30 minutes. According to Cleveland Clinic, influencer Lauren Giraldo first shared it on YouTube in 2019 and it took off on TikTok in 2020.
It is popular because it is simple and feels like a real workout without running. The steep incline makes your legs and lungs work hard at a walking speed, so there is less pounding than jogging. Use the walking workout timer on the 12-3-30 preset to count down the 30 minutes and show your treadmill settings in mph or km/h.
What are the 12-3-30 treadmill settings?
| Setting |
Classic 12-3-30 |
In metric |
| Incline |
12% |
12% |
| Speed |
3.0 mph |
about 4.8 km/h |
| Time |
30 minutes |
30 minutes |
Some treadmills show incline as a level rather than a percent grade, and a level is not always the same as a percent, so check your manual. Many home treadmills also have a lower maximum incline; if yours stops below 12%, use its top setting and judge the effort with the talk test.
How do you do 12-3-30 safely, step by step?
- Warm up on the flat. Walk 3 to 5 minutes at 0 to 1% incline and an easy pace. The original routine does not include this, but it makes the first minutes more comfortable.
- Raise the incline to 12% and the speed to 3 mph. Do it gradually over a minute.
- Walk tall without holding the rails. Keep your chest up, swing your arms and take shorter steps. Leaning on the rails or the console takes load off your legs and changes your posture.
- Keep going for 30 minutes. Expect heavy breathing and burning calves. You should still be able to say short phrases.
- Cool down. Lower the incline back to flat and walk easy for a few minutes before you step off.
How many calories does 12-3-30 burn?
It depends on your weight, fitness and whether you hold the rails, so treat any single number as a rough guide. Cleveland Clinic exercise physiologist Katie Lawton says the calorie burn at a 12% incline is nearly double that of walking on a flat surface.
The only lab study of the workout so far measured it directly. In a 2025 study at the University of Nevada, Las Vegas, 14 young, recreationally active adults (average age 25) did 12-3-30 and, on another day, a self-paced run that used the same energy. 12-3-30 used about 308 calories in 30 minutes, or about 10.2 calories a minute. Running burned calories faster, at about 13.1 a minute, so the run finished in about 24 minutes. During 12-3-30, a bigger share of the energy came from fat: about 41% versus 33% when running.
What that study does not show
- It was small and young. 14 active adults in their mid-20s are not a good guide for beginners or older adults.
- Rails were allowed, which is easier than the original rule.
- It measured one session. A higher share of energy from fat during exercise is not the same as losing more body fat over weeks.
For weight, the total you burn across the week, and your eating habits, matter far more than the fuel mix of one workout.
A 6-week beginner ramp to 12-3-30
The full routine is hard for most beginners. Cleveland Clinic suggests starting with 30 minutes on the flat or a lower incline such as 5%, a slower pace or less time. Change one setting at a time:
| Week |
Incline |
Speed |
Time |
Days |
| 1 |
4% |
2.5 mph (4.0 km/h) |
15 min |
3 |
| 2 |
6% |
2.5 mph (4.0 km/h) |
20 min |
3 |
| 3 |
8% |
2.8 mph (4.5 km/h) |
20 min |
4 |
| 4 |
10% |
2.8 mph (4.5 km/h) |
25 min |
4 |
| 5 |
12% |
3.0 mph (4.8 km/h) |
25 min |
4 |
| 6 |
12% |
3.0 mph (4.8 km/h) |
30 min |
4 to 5 |
If a week feels too hard, repeat it. The timer has Starter (6%, 2.5 mph, 20 minutes), Build (9%, 2.8 mph, 25 minutes) and Classic levels, and prints this ramp on one page.
Can you do 12-3-30 outdoors on a hill?
Partly. A 12% grade is steep: it climbs 12 feet for every 100 feet forward. Few outdoor hills hold that grade for long, and walking back down puts a different load on your knees and thighs. Outdoors, look for a long hill and walk up it briskly, then walk down at an easy pace, for 30 minutes. Time the total, not the climb, and expect it to feel different from the treadmill version.
|
Treadmill |
Outdoor hill |
| Incline |
Fixed 12% |
Changes, often less than 12% |
| Speed |
Fixed 3 mph |
Set by you |
| Downhill |
None |
Every lap, harder on the knees |
| Weather |
Not a factor |
Rain, ice and dark evenings |
Who should be careful with 12-3-30?
The steep incline loads your calves, Achilles tendons and lower back, and raises your heart rate quickly. Start lower if you are new to exercise. Check with your doctor first if you have a heart or lung condition, high blood pressure, joint, back or balance problems, or are pregnant. Use the treadmill safety clip, and stop if you feel chest pain, dizziness or unusual shortness of breath. If you need to hold on to keep going, Cleveland Clinic advises lowering the incline or the speed instead.
12-3-30 vs 6-6-6 and Japanese walking
12-3-30 is the hardest of the three walking trends minute for minute, and it needs a treadmill. The 6-6-6 walking rule is a longer, steady brisk walk you can do anywhere, and Japanese walking alternates 3 slow and 3 fast minutes for 30 minutes, the only one tested as a program in trials. Five 30-minute 12-3-30 sessions a week add up to the 150 minutes of moderate activity the CDC recommends for adults; add strength work on 2 days to cover the rest.
To keep it going past the first month, try the 30-day walking habit plan, build an exercise plan around your day or read is walking enough exercise. More ideas are in the exercise guides.
