HIV prevention tool
PrEP Eligibility Calculator: Do You Need PrEP?
PrEP is a highly effective medicine that prevents HIV. This calculator uses the validated HIRI-MSM risk score for gay and bisexual men, other men who have sex with men, and transgender women. Answer 7 questions, anonymously, in your browser, to see whether PrEP is recommended for you, then take the result to a provider.
PrEP eligibility calculator
The HIRI-MSM is a screening aid, not a diagnosis or a prescription. Only a clinician can decide whether PrEP is right for you: a below-threshold score does not rule PrEP out, and the CDC recommends it for anyone who wants it.
The basics
What is PrEP?
PrEP (pre-exposure prophylaxis) is medicine taken by people who are HIV-negative to keep them that way. Taken as prescribed, it is one of the most effective HIV-prevention tools there is: reducing the risk of getting HIV from sex by about 99%, and from injection drug use by at least 74%.
PrEP only protects against HIV. It does not prevent other STIs like chlamydia, gonorrhea, or syphilis, so it's used alongside condoms, regular testing, and, where appropriate, doxy-PEP.
Your options
The forms PrEP comes in
There are now four FDA-approved kinds of PrEP, two daily pills and two long-acting shots, plus an off-label on-demand option. Not sure which fits? Our Which PrEP is right for me? tool walks you through it.
Daily pill
Truvada (generic) or Descovy, taken once a day. The most established option, with decades of data.
Every-2-month shot
Apretude (cabotegravir), a long-acting injection given by a provider every 2 months, no daily pill.
Twice-yearly shot
Yeztugo (lenacapavir), the newest option (2025): just two injections a year, over 99.9% effective in trials.
On-demand (2-1-1)
An event-driven pill schedule some men who have sex with men use around sex. Ask a provider if it fits you.
CDC guidance
Who should consider PrEP?
This calculator scores HIV risk for men who have sex with men and transgender women, but PrEP is for a wider range of people. The CDC says a provider should discuss PrEP with everyone who is sexually active, and prescribe it to anyone who asks for it, even without a specific risk factor. It's especially worth starting if any of the following apply:
- You have a sexual partner living with HIV (especially if their virus is not known to be undetectable).
- You don't always use condoms with partners whose HIV status you don't know.
- You've had a bacterial STI (chlamydia, gonorrhea, or syphilis) in the past 6 months.
- You share needles, syringes, or other equipment to inject drugs.
- You've recently taken PEP (emergency post-exposure HIV medicine) and your risk is ongoing.
PrEP requires a negative HIV test to start and a check-in with a provider every 3 months, which keeps it working safely and pairs it with routine STI testing.
Access & cost
How to get PrEP, and what it costs
Where to start
A primary-care provider, sexual-health or HIV clinic, or a telehealth PrEP service can prescribe it. You'll get a quick HIV test and a few labs first, then a prescription and a follow-up plan.
Usually $0 out of pocket
Because PrEP has the USPSTF's top (Grade A) rating, most insurance must cover the medication, visits, and labs with no cost-sharing. Uninsured? Free 340B telehealth services, drug-maker assistance, and state programs still get most people to $0, see our PrEP cost guide.
Keep going
Related tools & guides
Sources
Where this tool comes from
The score is the published HIRI-MSM index; the prevention guidance is drawn from the CDC's clinical practice guideline and the USPSTF recommendation. We don't reinterpret them.
Medically Reviewed & Fact-Checked · Updated
Reviewed by EasySTD Editorial Team
Compiled and checked by EasySTD's editorial team against CDC and public-health sources. This is educational information, not a substitute for advice from a licensed clinician. Our editorial guidelines →
4 Sources
Data & references
- CDC, Preexposure Prophylaxis for the Prevention of HIV Infection in the U.S., 2021 Updatehttps://www.cdc.gov/hiv/pdf/risk/prep/cdc-hiv-prep-guidelines-2021.pdf
- CDC: PrEP (Pre-Exposure Prophylaxis)https://www.cdc.gov/hiv/risk/prep/index.html
- Smith DK et al.: Development of the HIRI-MSM screening index (JAIDS, 2012)https://journals.lww.com/jaids/fulltext/2012/08010/development_of_a_clinical_screening_index.14.aspx
- USPSTF: PrEP for the Prevention of HIV (Grade A)https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/prevention-of-human-immunodeficiency-virus-hiv-infection-preexposure-prophylaxis
EasySTD is an information and comparison directory, not a healthcare provider. This calculator is general information based on a published screening tool: it is not medical advice, a diagnosis, or a prescription, and it does not create a doctor-patient relationship. Always consult a qualified clinician.
Good to Know
PrEP eligibility: frequently asked questions
The essentials on scoring, PrEP options, and access.
Who is this PrEP calculator for?
It uses the HIRI-MSM (HIV Incidence Risk Index for men who have sex with men), a screening score validated in U.S. studies for gay and bisexual men, other men who have sex with men, and transgender women. If you don't fall into those groups, the score won't be accurate, but PrEP may still be right for you. The CDC recommends PrEP for anyone with an HIV-positive partner, a recent bacterial STI, condomless sex with partners of unknown status, or anyone who simply requests it. Talk to a provider.
What does my score mean?
The HIRI-MSM runs from 0 to 47. A score of 10 or higher is the validated threshold that flags increased HIV risk, at that level the CDC and the tool's authors say PrEP should be discussed and offered. A score of 10 was associated with roughly a 2% chance of acquiring HIV per year in the original studies, and a score of 25 or more with about 7% per year. A score below 10 does not mean you can't or shouldn't take PrEP.
Does a low score mean I don't need PrEP?
No. The 2021 CDC clinical practice guideline is explicit: PrEP should be prescribed to anyone who asks for it, even without a specific risk factor. A below-threshold score means this particular screen didn't flag elevated risk: it does not rule out PrEP, and it doesn't mean your risk is zero. Your own judgment about your situation matters, and a provider can help you decide.
What is PrEP and how well does it work?
PrEP (pre-exposure prophylaxis) is medicine taken by HIV-negative people to prevent HIV. Taken as prescribed, oral PrEP reduces the risk of getting HIV from sex by about 99%. It comes as a daily pill (Truvada or Descovy) or a long-acting injection (Apretude / cabotegravir) given every two months. PrEP only prevents HIV, not other STIs, so it's paired with condoms and regular testing.
How do I get PrEP, and what does it cost?
PrEP is prescription-only. A primary-care provider, sexual-health or HIV clinic, or telehealth service can prescribe it after a quick HIV test and a few labs, with follow-up every three months. Because the USPSTF gives PrEP its top (Grade A) rating, most insurance plans must cover it, including the medication and the required visits and labs, with no out-of-pocket cost. If you're uninsured, free 340B telehealth services, manufacturer assistance programs, and state PrEP funds still get most people to $0 (the federal Ready, Set, PrEP program ended in 2025). See our PrEP cost guide for the details.
Is my information private?
Yes. This calculator runs entirely in your browser. Your answers are never sent to a server, saved, or shared, refresh the page and they're gone. We can't see them and neither can anyone else.
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