Health Calculators
Toothbrush replacement date calculator.
Enter the date you started your current brush, choose 3 or 4 months, and how many people share the schedule. You get the next four change dates and the brushes and cost per year. The ADA says to replace toothbrushes every three to four months, or sooner if the bristles are frayed.
Your brush
Change dates
Fill the form and press Get dates.
How the dates are worked out
Each change date is your start date plus 3 or 4 months, repeated. If the date does not exist in the later month (the 31st into a month with 30 days) the last day of that month is used. Brushes per year = 12 ÷ months between changes × people, and cost per year = brushes per year × price.
Worked example. Brush started 2026-10-08, changed every 3 months, 4 people at $4 each. Change dates: 2027-01-08, 2027-04-08, 2027-07-08, 2027-10-08. That is 16 brushes and $64.00 a year. Changing every 4 months for one person gives 3 brushes a year.
What the ADA says. Replace toothbrushes every three to four months, or sooner if the bristles are visibly matted or frayed, and a worn brush will not clean as well. Soft bristles are recommended for manual and powered brushes. Change it sooner on your own judgement if the bristles look worn, whatever date this tool shows. For replacement heads on an electric brush, follow the maker's guidance as well.
Sources (each opened 2026-10-08): ADA Oral Health Topics: Toothbrushes (last updated August 2026); MouthHealthy (ADA): Toothbrushes.
FAQ
How often should I replace my toothbrush?
The ADA says every three to four months, or sooner if the bristles are visibly matted or frayed.
What if my brush still looks fine at three or four months?
The ADA gives three to four months as the replacement interval, and says to replace sooner if the bristles are visibly matted or frayed. Looking fine is not a reason to keep it past that interval.
How many toothbrushes do I need per year?
Three or four per person at the ADA interval, depending on whether you change every 4 or every 3 months. Multiply by the number of people.
Does this apply to electric toothbrush heads?
The ADA statement is about toothbrushes. Heads usually come with the maker's own guidance, so follow that and use this date as a cross-check.
Why does the date sometimes land on the 28th?
When the start day does not exist in the later month, the tool uses that month's last day, so a start on the 30th becomes the 28th in February.
Disclaimer
General information and arithmetic on numbers you enter, not dental advice. Your dentist decides what treatment you need and when. Plans, prices and results differ from the simple model used here.