You probably spend more time sitting than any other position. At your desk. In your car. On your couch. At meals. If you’re like most adults, you sit for 8-15 hours a day.
With that much time in one position, small errors compound. Sitting slightly wrong for 8 hours a day, 5 days a week, 50 weeks a year—that’s a lot of time training your body into poor posture.
The good news: sitting correctly isn’t complicated once you understand the principles. Let’s go through exactly how to sit properly in every common situation.
The Basics of Good Sitting Posture
Regardless of where you’re sitting, these principles apply:
Support your lower back’s natural curve
Your lower back (lumbar spine) should have a slight inward curve. Most chairs don’t support this naturally. Use the chair’s lumbar support, add a lumbar pillow, or roll up a towel and place it behind your lower back.
Sit on your sit bones
Your pelvis has two bony bumps at the bottom—your ischial tuberosities, or “sit bones.” You should be sitting on these, not rolled back onto your tailbone. This creates the foundation for a neutral spine.
To find them: sit, then rock your pelvis forward and back. Feel the point where you’re balanced on the bony parts. That’s it.
Head over shoulders
Your head should be balanced over your shoulders, not jutting forward. This is where most people fail—especially when looking at screens. See forward head posture.
Shoulders over hips
Your shoulders should stack over your hips, not rounded forward. See rounded shoulders if this is a problem.
Feet on the floor
Your feet should rest flat on the floor (or on a footrest). This provides a stable base and keeps your hips at the right angle.
90-90-90
A useful shortcut: 90-degree angles at your ankles, knees, and hips. Not rigidly, but approximately.
Sitting at a Desk
This is where most posture damage happens. Here’s how to set up properly.
Chair height
Adjust your chair so your:
- Feet rest flat on the floor
- Thighs are parallel to the floor (or slightly angled down)
- Hips are at 90-100 degrees
If your desk is too high to allow this, use a footrest.
Chair depth
The seat should support your thighs but leave a few inches between the seat edge and the back of your knees. Sitting too deep makes it hard to use the backrest.
Lumbar support
Your chair should support your lower back curve. If it doesn’t, add a lumbar support cushion or rolled towel. Position it at the small of your back, not higher.
Armrests
If you use armrests, they should be at a height that allows your shoulders to relax. Too high causes shoulder elevation. Too low provides no support.
Many ergonomic experts suggest removing armrests entirely if you tend to lean on them asymmetrically.
Screen height
The top of your screen should be at or slightly below eye level. You shouldn’t have to look up or down. If you use a laptop, elevate it and use an external keyboard.
Screen distance
About arm’s length away—roughly 20-26 inches. Far enough to see comfortably, close enough that you don’t lean forward.
Keyboard and mouse
Close enough that your elbows stay near your body at about 90 degrees. If you’re reaching forward, everything else is compromised.
For complete desk setup guidance, see desk posture exercises.
Sitting in a Car
Car seats are often ergonomically terrible. Here’s how to optimize:
Seat position
- Close enough to reach pedals without stretching
- Far enough that your legs aren’t cramped
- Hips slightly higher than knees (many seats angle back too much)
Lumbar support
Use the car’s built-in lumbar support if it has one. Otherwise, use a lumbar cushion. Lower back support is crucial for long drives.
Headrest
Should touch the middle/upper back of your head—not your neck, not empty space behind you. Adjust the angle so your head naturally rests against it.
Steering wheel
Hands at 9 and 3 (not 10 and 2, which is outdated and causes shoulder strain). Arms should be slightly bent, not fully extended.
Mirror check
Adjust your mirrors when sitting with good posture. Then if you slouch during the drive, you won’t be able to see properly—a natural reminder to sit up.
Long drives
Stop every 1-2 hours to stand, stretch, and walk. Your spine needs breaks from the compression of sitting.
Sitting on a Couch
Couches are posture traps. They’re designed for comfort, not alignment.
The problems with couches
- Soft cushions don’t support the spine
- Deep seats cause you to slouch back
- Low seats create awkward hip angles
- They encourage lying/lounging rather than sitting
If you’re on the couch anyway
- Sit toward the front where cushions are firmer
- Use a pillow behind your lower back
- Keep feet on the floor, not tucked under you (occasionally fine, not for hours)
- Don’t sit in the same position for hours
For watching TV
- Sit, don’t lie
- Screen should be at eye level (not too high or low)
- Take breaks to move
Consider alternatives
For long periods of relaxation at home, consider a supportive armchair instead of a couch. Or alternate between couch time and moving.
Sitting on the Floor
If you sit on the floor (for meditation, playing with kids, etc.):
Cross-legged
- Sit on a cushion to elevate your hips above your knees
- This tilts your pelvis forward, making it easier to sit upright
- Don’t round your lower back
Kneeling (seiza)
- Kneel with a cushion between your calves and thighs
- This naturally supports an upright spine
- Can be hard on knees for extended periods
90-90 position
- One leg in front of you, bent 90 degrees
- One leg to the side, bent 90 degrees
- Good for hip mobility while sitting
General floor sitting tips
- Change positions frequently
- Use props (cushions, blocks) to make upright posture easier
- Don’t sit in any single position for too long
The Movement Rule
No matter how perfectly you sit, static sitting is problematic. Your body needs movement.
Every 30-45 minutes:
- Stand up
- Walk briefly
- Stretch
- Change position
You can have perfect ergonomics and still develop problems from lack of movement. Build breaks into your routine.
Common Sitting Mistakes
Crossing legs
Crossing your legs rotates your pelvis and creates asymmetrical tension. Occasional crossing is fine. Hours of it is not. If you must cross, alternate which leg is on top.
Sitting on one leg
Same problem as crossing—asymmetry. Your spine compensates for the unevenness.
Perching on the edge
Sitting on the edge of your chair without back support leaves your back muscles working constantly. Sit back and use the backrest.
Leaning to one side
Common when using a mouse with one hand. Creates muscle imbalances over time. Stay centered.
Looking down at phone
Tech neck while sitting compounds the damage. Bring phone to eye level.
Working from bed
Beds are for sleeping. Working in bed guarantees poor posture—there’s no way to sit properly.
Building Sitting Awareness
Beyond setup, you need awareness. Your posture will slip during the day. The goal is to notice and correct.
Posture check-ins:
- Set random alarms as reminders
- Use cues (every time you check email, check posture)
- Notice when you’re uncomfortable—it’s often a posture signal
What to check:
- Is my head forward?
- Are my shoulders rounded?
- Is my lower back supported?
- Am I sitting on my sit bones?
Over time, good posture becomes your default. But it takes consistent awareness to build that habit.
Exercises to Support Sitting
Even perfect sitting causes stiffness. Counter it with exercises:
- Desk posture exercises - do these at work
- 10-minute posture workout - daily routine
- Hip flexor stretches - counter tight hip flexors from sitting
- Core exercises - support your spine
For the complete picture on posture, see how to fix bad posture.
Sitting well won’t fix existing posture problems. But sitting poorly makes everything worse. Start with your setup, build awareness, take breaks, and pair it all with targeted exercises. Your spine is with you for life—treat it well.
Related articles:
The Posture Workout app includes posture reminders and desk-friendly exercises to support better sitting habits. Download it free →