HIV Risk Calculator & Personalized Risk Report
Use our private HIV risk calculator to estimate the statistical risk of HIV transmission from a single sexual encounter.
The HIV Risk Report analyzes your exposure type, sexual role, condom use, partner HIV status, PrEP, ART, country-level HIV data and other relevant risk factors to generate a personalized 6-page report.
Replace panic with probability.
🕓 Last updated: 3 August 2026
HIV Risk Report is a private, educational HIV risk calculator and 6-page personalized report that estimates the statistical risk of HIV transmission from a single sexual encounter. It combines published epidemiological data, country-level HIV information and encounter-specific factors to explain what is driving the result and present the final estimate as both a percentage and a "1 in X" figure. The report does not diagnose HIV or predict an individual outcome. It is designed to provide realistic context and clear next-step guidance, including testing information when appropriate.
Private encounter analysis using evidence-based HIV transmission data.
How Our HIV Risk Calculator Estimates Your Risk
HIV transmission risk is not the same for every sexual encounter. The probability changes depending on the type of exposure, whether you were insertive or receptive, your partner's HIV status and treatment status, condom use, PrEP use and other biological or behavioral factors.
Our HIV risk calculator combines the details of the encounter you describe with published epidemiological data to create a statistical estimate of HIV transmission risk. Instead of treating every exposure as equally risky, the Risk Engine evaluates the individual components that can increase or decrease the probability.
What Affects HIV Transmission Risk?
Exposure Type
Anal, vaginal and oral sex have different baseline HIV transmission probabilities. The Risk Engine begins with the type of sexual exposure reported.
Insertive or Receptive Role
Transmission probability differs depending on which partner was insertive or receptive because different tissues and biological pathways are exposed.
Partner HIV Probability
Known HIV status, country-level prevalence and relevant partner factors help establish the probability that HIV was present in the first place.
ART and Viral Suppression
When treatment status is relevant, the model considers HIV treatment coverage and viral suppression because effective ART can dramatically change transmission risk.
Condoms and PrEP
Protective measures such as condoms and PrEP are applied as risk-reducing factors when they are relevant to the encounter.
Encounter-Specific Factors
The calculation can also account for applicable factors such as ejaculation, wounds or inflammation, circumcision and recent partner-risk information.
Your final HIV risk estimate is presented as both a percentage and a "1 in X" figure, together with an explanation of what drove the result. An HIV risk calculation cannot diagnose HIV. Testing is required to determine HIV status.
How It Works
Your personalized HIV Risk Report is generated in under 30 minutes.
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Answer questions: Confidentially enter details about your sexual encounter, partner and location.
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Risk Engine analysis: Your answers are mapped to an epidemiological framework using exposure-specific risk data, country-level prevalence and treatment information.
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Receive your report: Get a personalized 6-page PDF containing your calculated HIV risk estimate, the factors that influenced it and clear next steps.
Why Trust the Results?
Built around published HIV transmission probability data.
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Evidence-based framework: The HIV risk calculator uses published transmission studies and epidemiological data rather than a generic high-risk or low-risk questionnaire.
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Transparent calculation logic: See our Risk Engine methodology and how the different factors influence the final estimate.
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Country-specific context: Estimates can incorporate the country selected, including HIV prevalence and treatment coverage assumptions when relevant.
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Encounter-specific output: The final estimate is built from the details you provide instead of relying only on broad population averages.
Answer the encounter questions and receive your personalized 6-page HIV Risk Report.
HIV Risk Calculator Resources
Learn more about HIV transmission probability, how the Risk Engine works and how different types of exposure affect statistical risk.
Latest Risk Engine Update
The HIV Risk Report calculation model is regularly reviewed as evidence, methodology and report functionality evolve.
VERSION 6.7
- Evidence Audit of Risk Multipliers: Risk multipliers in the calculation framework were cross-referenced against the supporting peer-reviewed evidence used by the model.
- Wound and Inflammation Adjustment: The applicable modifier was fine-tuned to better reflect published meta-analytic evidence.
- Circumcision Factor Update: Circumcision logic was harmonized across relevant exposure pathways where the same biological mechanism applies.
- On-Demand PrEP Precision: The protection assumption for on-demand PrEP was adjusted to more closely reflect the IPERGAY evidence used by the model.
- Multiple Partner Factor: The applicable partner-risk modifier was recalibrated against supporting epidemiological literature.
- Intravenous Drug Use Logic: Partner-risk handling was reorganized within the formula to improve mathematical clarity and transparency.
- Expanded Source Citations: Additional peer-reviewed sources were added directly to the report reference section.