How to Use the Tdap Booster Calculator
Tetanus is caused by bacteria entering the body through a wound, and vaccine protection fades over time — which is why adults need periodic booster shots. This calculator takes the years since your last Tdap/Td dose and whether you currently have a wound, then tells you whether a booster is due now or how long you can safely wait.
The standard CDC/ACIP recommendation is a booster every 10 years. But a deep or dirty wound — contaminated with dirt, rust, or from an animal bite — changes the calculation. If you have this kind of wound and it's been 5 or more years since your last dose, an immediate booster is recommended regardless of the 10-year schedule, since these wounds carry a higher risk of tetanus infection.
This calculator is a general reference based on standard booster intervals and doesn't account for your exact vaccination history, allergies, or immune status. If you're unsure of your last dose date or have a serious wound, don't wait — see a doctor or clinic right away. Check the FAQ below for more details.
Frequently Asked Questions
CDC/ACIP recommends a booster every 10 years. If you've never had Tdap as an adult, the first dose should be Tdap, with Td or Tdap boosters every 10 years after that.
Yes. If you have a deep or dirty wound and it's been 5 or more years since your last dose, CDC guidance recommends an immediate booster regardless of the 10-year schedule. Wounds contaminated with dirt, rust, or from animal bites need extra caution.
If you're unsure of your exact vaccination date, it's safest to assume a booster may be needed and check your immunization record with a doctor or clinic before deciding.