HIV Risk Report

Built to give peace of mind and replace panic with probability.

Calculate your HIV risk using our private, proprietary assessment tool.

Powered by country-level data from the CDC and UNAIDS.

🕓 Last updated: 15 May 2026

RISK_ENGINE_v6.6 - SYSTEM ONLINE

HIV Risk Report is a private, educational tool that estimates the statistical risk of HIV virus transmission from a single sexual encounter. It uses published epidemiological data from sources such as the CDC and peer-reviewed medical studies to translate multiple risk factors into one clear probability, shown as both a percentage and a “1 in X” figure. This report does not diagnose the HIV virus or predict individual outcomes, but it helps replace vague anxiety with realistic context and guidance on appropriate next steps, including testing when needed.


Start Your 6-Page Personalized
HIV Risk Assessment

How it works

Your personalized report is generated in under 30 minutes.

  1. Answer questions: Confidentially enter details about your encounter and location.

  2. Engine analysis: Inputs map to an epidemiological framework using country-level prevalence and treatment data.

  3. Receive report: Get a 6-page PDF with your calculated estimate and clear next steps.

Why trust the results

Built on the probability logic used in HIV research.

  • Validated algorithms: Built from peer-reviewed HIV transmission studies and calibrated against global data.

  • Transparent logic: See our calculation logic, including how each multiplier affects your final number.

  • Internationally relevant: Estimates are adjusted using the country you select, including treatment coverage assumptions when partner ART status is unknown.

  • Evidence-driven tool: A probability model designed to support clear, informed decisions instead of guessing.

Start Your 6-Page Personalized
HIV Risk Assessment

Version updates

Our risk engine is refined based on updated data. Methodology and data sources.

For deeper education, read our HIV risk calculator guide and browse our blog.

VERSION 6.6
  • Number-Linked Risk Summaries: Improved the main analysis sections so the written explanation is tied directly to the actual numbers in the report. Version 6.6 now guides the summary to explain the partner HIV estimate, per-act transmission risk, and each relevant upward or downward modifier in the same order they appear in the calculation. This makes the report easier to follow because users can see how the narrative, calculation table, and final risk estimate all connect.
  • Cleaner Intake Flow: Reorganised the required exposure questions into a clearer numbered sequence and made the exposure date an explicit required field, which is essential for PEP eligibility and testing-date calculations. Version 6.6 also clarifies answer options for uncertain fields such as intravenous drug use and multiple recent partners, helping the report collect cleaner inputs before any risk calculation is generated.
  • Clearer Final Risk Equation: Added a single master equation showing how the final HIV risk is calculated from the adjusted partner HIV likelihood, base transmission risk, and each applicable modifier. The previous version already included these factors across the Partner HIV Estimate, modifier list, and Calculation Breakdown table, but Version 6.6 makes the full calculation chain explicit and easier to audit.
  • Cleaner Calculation Breakdown Table: Fixed the table logic so intravenous drug use is treated as its own calculation factor rather than being grouped under the ejaculation condition. This makes the final risk table more accurate, easier to audit, and better aligned with the actual formula used in the report.
  • Clearer ART Cascade Explanation: Made the ART section easier to understand in cases where the partner’s HIV status or treatment status is unknown. Version 6.6 more clearly shows how the report uses real-world treatment cascade data, including diagnosis rates, ART coverage, viral suppression, unsuppressed probability, and the safety buffer, to calculate the ART multiplier used in the final risk estimate.
  • More Structured Testing Guidance: Tightened the testing section by requiring RNA, fourth-generation lab, and antibody-based tests to appear as separate cards, each with a test type, description, and calculated date. Version 6.6 also makes the testing-date logic explicit, using 14 days for RNA testing, 28 days for fourth-generation lab testing, and 90 days for antibody-based testing.
  • Sharper PEP Decision Tree: Expanded the PEP instructions into clearer scenario-based guidance. Version 6.6 now separates users who are within the 72-hour window, near the end of the window, outside the window, or already strongly protected by correctly taken PrEP. This helps the report provide more specific next-step guidance instead of relying on a generic PEP paragraph.
  • Stronger Final HTML Quality Checks: Consolidated the final-output rules into a clearer pre-render checklist. Version 6.6 more explicitly checks for unresolved placeholders, leftover template syntax, markdown formatting, asterisk characters, duplicate sections, calculation mismatches, and PDF export issues before the report is generated.
  • More Enforceable Card Layout Rules: Strengthened the existing card-based design requirements by defining exactly how key sections should be structured. Version 6.6 now requires named Step Two analysis cards, separate testing cards with test type, description, and date, a two-column What Helped and What Hurt card, a structured ART cascade table, and more polished card treatment for the perspective, Real Talk, and Your Path Forward sections.
VERSION 6.5
  • Card-Based UI Architecture: Transitioned key report sections, including Step Two analysis paragraphs and Testing Options, into distinct, self-contained cards to improve readability and information retention.
  • Visual Risk Indicators: Implemented clear visual cues, including check marks for protective factors and cross icons for risk factors, in the “What Helped vs. What Hurt” section for faster scanning.
  • Enhanced Data Presentation: Restructured the HIV Risk Cascade formula into a detailed table for transparency, and modernised the “Path Forward” section with iconography to emphasise actionable next steps.
VERSION 6.4
  • Sex Worker Risk Model Update: Refined how sex work is incorporated into partner prevalence estimates, using region-specific multipliers that are more conservative and more realistic.
  • Improved Key Population Handling: Prevents over-inflation when a key population baseline is already being used, for example MSM, reducing double counting while still accounting for increased exposure risk.
  • Stability and Trust: Added caps and dampening logic to keep outputs within credible real-world ranges, improving consistency across regions.
VERSION 6.3
  • Report Design: Re-designed the entire report for a more modern look and feel.
  • Geo-Specific Accuracy: The risk engine’s analysis is now more precise by explaining how country-specific data, including HIV prevalence and healthcare system effectiveness, is used to calibrate the final probability.
VERSION 6.2
  • RNA Testing: Report now includes suggested dates for RNA testing based on the encounter date.
VERSION 6.1
  • Transparency Update: The FAQ section now includes a full breakdown of the HIV Treatment Cascade equation, showing exactly how we calculate risk for partners with an unknown ART status.
  • Empowerment Update: Reports now conclude with a “Path Forward” section, reframing the experience from anxiety to agency and highlighting the knowledge the user has gained.
VERSION 6.0
  • Major Update I: Refined the sex worker risk multiplier with region-aware logic based on UNAIDS prevalence data.
  • Major Update II: Integrated PrEP, Pre-Exposure Prophylaxis, logic into the risk calculation.
  • The model now accounts for user adherence with specific pathways for perfect daily use, on-demand dosing (2-1-1), missed doses, and recent initiation.
  • Each adherence level is mapped to a clinically backed risk reduction multiplier, for example up to 99% for perfect use.
VERSION 5.6
  • Patched linguistic ambiguity in the risk modifier output.
VERSION 5.5
  • Enhanced tissue integrity modelling for transmission probability.
  • Corrected HIV prevalence data streams for MSM versus general population.
VERSION 5.4
  • Implemented an ART logic override: the template now automatically uses the more realistic “Don’t Know” ART calculation if the partner’s overall HIV status is “Don’t Know”, even if “No” was selected for the ART question.
  • Updated circumcision logic: the upward risk multiplier for being uncircumcised now only applies if a condom was not used.
VERSION 5.3
  • The protective benefit of “no ejaculation” is now correctly applied only to receptive partners. Previously this required a manual QA change.
VERSION 5.2
  • Report now includes a “Comparison to Other STIs” section showing relative likelihoods versus HIV.
VERSION 5.1
  • Added test timing calculator based on the user’s exposure date.
  • Shows personalised lab and oral test dates to avoid false negatives.
VERSION 5.0
  • ART coverage logic improved, now factoring in three country-level statistics, diagnosis rate, treatment access, and viral suppression, to give a more realistic picture of how many people are actually suppressed.
  • Sex worker risk logic revised, adjusted to be more conservative while still accounting for higher exposure rates due to occupational partner turnover.
  • Multiple partners logic refined, risk estimates now better reflect the increased exposure likelihood when a partner has had two or more partners in the past six months.
VERSION 4.9
  • ART coverage now splits by population: MSM versus general public.
  • Improves accuracy by reflecting real-world disparities in ART access for MSM.
VERSION 4.8
  • Expanded risk pathway logic to account for instances where the user is not circumcised.
VERSION 4.6 & 4.7
  • Wound and inflammation risk now included, increasing transmission estimates if the user had open cuts, sores, or irritation during sex, only applied when no condom was used.
  • Step Two now clearly explains how wound-based risk affects overall probability, using plain language.
  • The full breakdown of probability logic now includes a clearer explanation of how the partner’s HIV estimate and act-specific transmission risk combine to calculate final odds.
VERSION 4.5
  • PEP guidance now adapts to risk tier, clarifying when it is typically not recommended but still available for high-anxiety or anal sex cases.
  • New “What If It Was Anal?” FAQ added for users who select “multiple sex types” without specifying the act.
  • “What We Recommend” section rewritten for sharper tone, emotional clarity, and faster readability.
VERSION 4.4
  • Real-world ART logic now applies regional treatment coverage rates when ART status is unknown.
  • Expanded risk pathway logic to include role-specific, insertive versus receptive, modifiers.
  • MSM-specific prevalence now replaces general population prevalence for male-male encounters.
VERSION 4.0
  • Introduced emotional reinforcement and alternate scenarios to reduce panic.
  • Added personalised risk recommendations based on calculated probability.
  • Cleaned up visual flow for mobile-first readability.
VERSION 3.0
  • Transitioned to per-act risk modelling using fraction and percentage logic.
  • Integrated global gender-stratified HIV prevalence estimates.
  • Upgraded condom effectiveness to reflect real-world meta-analytic data.
  • Introduced transparent breakdown of all conditional inputs in Step Three.