Handwashing is one of the most effective ways to stop the spread of germs, but it only works if you do it long enough. The entire handwashing process — from turning on the water to drying your hands — should take about 30 to 40 seconds. The most important part is lathering and scrubbing with soap for at least 20 seconds. That 20‑second scrub is the key number recommended by health authorities, and the extra time for wetting, rinsing, and drying brings the total to around half a minute.
How Many Seconds Should the Entire Handwashing Process Take?
The U.S. Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) both recommend scrubbing your hands with soap for at least 20 seconds. From start to finish — wetting hands, applying soap, scrubbing for 20 seconds, rinsing, and drying — the process typically takes 30 to 40 seconds. If you are using a hand sanitizer instead, you need to rub it over all surfaces of your hands for about 20 seconds until dry.
Why Is 20 Seconds the Recommended Time?
Soap and friction work together to break down the outer layer of many viruses and bacteria. Scrubbing for 20 seconds gives enough contact time for the soap to lift germs off your skin and for the mechanical action of rubbing to dislodge them. The 20‑second recommendation is based on decades of laboratory testing and field studies. Research shows that shorter washes — 5 or 10 seconds — remove far fewer germs. A 20‑second scrub consistently achieves a 99% or better reduction in many common pathogens when done properly.
What Does the Research Say About Handwashing Duration?
Several studies have examined how washing time affects germ removal. A 2020 study published in Infection Control & Hospital Epidemiology found that a 10‑second handwash removed significantly fewer bacteria than a 20‑second wash. The same study showed that increasing scrub time beyond 30 seconds did not provide a meaningful additional benefit. Other research has confirmed that 15 seconds is better than 5, and 20 seconds is better than 10. The consensus across multiple studies is that 20 seconds hits the sweet spot: long enough to be effective yet short enough to be practical for regular use.
How to Properly Wash Your Hands in 20 Seconds
Follow these steps to make sure your 20‑second scrub covers every surface:
- Wet your hands with clean running water, then turn off the tap if you are conserving water.
- Apply enough soap to cover all hand surfaces.
- Rub your hands together vigorously for 20 seconds. Make sure you scrub the backs of your hands, between your fingers, and under your nails.
- Rinse with clean running water.
- Dry with a clean towel or air dryer.
A good way to time yourself is to hum the “Happy Birthday” song twice from beginning to end. That takes roughly 20 seconds. Alternatively, you can hum any song that lasts about 20 seconds.
Can You Wash Your Hands Too Long?
Yes, washing for several minutes or using very hot water can damage the outer layer of your skin, leading to dryness, cracking, and irritation. Damaged skin is more likely to harbor germs because the protective barrier is broken. Washing for 20 to 30 seconds with warm or lukewarm water is sufficient and safe. If you wash your hands very frequently — for example, many healthcare workers do — using a mild soap and applying moisturizer afterward can prevent irritation.
What If You Don’t Have Soap and Water?
When soap and water are not available, the CDC recommends using an alcohol‑based hand sanitizer that contains at least 60% alcohol. Apply enough sanitizer to cover all surfaces of your hands and rub them together for about 20 seconds, or until the sanitizer is dry. Sanitizers do not remove all types of germs — for example, they are less effective against norovirus and Clostridium difficile — but they are a good backup when handwashing is not possible.
Common Mistakes That Reduce Handwashing Effectiveness
Even when people wash for 20 seconds, they often miss key areas. Studies using fluorescent lotion show that the most commonly missed spots are the thumbs, the backs of the hands, between the fingers, and under the fingernails. Another mistake is not rinsing off all the soap — leftover soap can cause irritation and may trap germs. Drying matters too: wet hands pick up and transfer germs more easily than dry hands, so always dry thoroughly with a clean towel. Lastly, avoid using a communal hand towel that is not changed regularly, as that can recontaminate clean hands.
Frequently Asked Questions
Is 10 seconds of handwashing enough?
No. Research shows that a 10‑second wash removes far fewer germs than a 20‑second scrub. Always aim for at least 20 seconds of lathering and scrubbing.
Does the water temperature matter for handwashing?
Not for germ removal. Warm water may feel more comfortable, but cold water is equally effective as long as you use soap and scrub for 20 seconds.
How can I time 20 seconds without a clock?
Hum the “Happy Birthday” song twice from start to finish, or sing any tune that lasts about 20 seconds. That gives you the correct duration.
Should I wash my hands longer after using the bathroom?
The same 20‑second rule applies. No additional time is needed if you wash all surfaces properly. However, many people skip thorough washing after bathroom use, so focus on technique rather than extra seconds.
