Calculator Inputs
Fill your context and controls, then submit.
Example Data Table
These sample scenarios illustrate how risk and recommended timeouts can change with context and controls.
| Scenario | Sensitivity | Privilege | Auth | Exposure | Risk Level | Suggested Idle | Suggested Absolute |
|---|---|---|---|---|---|---|---|
| Public customer portal | Moderate | Standard | MFA | Public | Medium | 15 min | 12 hr |
| Finance dashboard | High | Power | Phish-resistant MFA | Public | High | 10 min | 8 hr |
| Admin console | High | Admin | MFA | Partner | High | 5–10 min | 4–8 hr |
| Internal wiki | Low | Standard | Passwordless | Internal | Low | 20–30 min | 24–72 hr |
Formula Used
1) Risk score
The calculator assigns points to context: data sensitivity, privilege, exposure, authentication strength, device trust, threat activity, and compliance strictness. Convenience settings (like long-lived sessions) add points. Safeguards reduce points.
2) Recommended timeouts
A higher risk score maps to shorter recommended idle timeouts and shorter absolute lifetimes. Client type adjusts recommendations: mobile can be slightly longer; API tokens should be shorter.
3) Strength score
Strength Score = 50×min(1, recommended_idle/current_idle) + 30×min(1, recommended_absolute/current_absolute) + 20×(control_reduction/max_control_reduction). A higher score indicates stronger protection against session hijacking.
How to Use This Calculator
- Enter your current idle timeout, absolute lifetime, and warning behavior.
- Select context: sensitivity, privilege, exposure, authentication, and device trust.
- Check safeguards you actually enforce in production.
- Submit to view risk, recommended targets, and a strength rating.
- Export a CSV or PDF to document your policy decisions.
Why Idle Timeout Matters for Takeover Windows
Idle timeout limits the time an unattended session stays usable. Shorter values reduce exposure after device theft, shoulder surfing, or tab hijacking. For public browser apps, many teams target 10–20 minutes, while privileged consoles often tighten to 5–10 minutes. A warning 1–5 minutes before logout improves completion of in‑progress work without extending exposure. The calculator converts context into a risk score, then maps higher risk to shorter recommended idle targets.
Absolute Lifetime and Refresh Token Strategy
Absolute lifetime caps a session even with continuous activity, which helps when tokens leak silently. A common pattern is 8–24 hours for standard users and 4–8 hours for admins, then require a fresh login. Mobile clients sometimes need slightly longer caps to handle intermittent connectivity, but should rely on strong device trust. When refresh tokens are used, rotation and reuse detection meaningfully reduce replay risk. The tool recommends a lifetime and highlights gaps if your cap is longer than guidance.
Privilege and Data Sensitivity Weighting
Not all sessions carry equal impact. Administrative privilege, regulated records, and high-value actions raise the baseline risk points. Pair that with exposure (internet versus internal) and authentication strength, and the model quickly separates low-impact wiki access from finance dashboards. The result encourages shorter timeouts where a single compromised session could trigger irreversible changes or large data exports.
Control Stack That Raises the Strength Score
Controls reduce risk points and also add to the strength score. Step-up verification for sensitive actions blocks “silent” takeovers, while server-side revocation ensures logout actually ends access. IP or device change checks catch token reuse from new environments. For web clients, Secure, HttpOnly, and SameSite cookie flags reduce theft and CSRF paths. For APIs, short-lived access tokens reduce blast radius.
Operational Metrics to Review Quarterly
Use session telemetry to validate policy choices. Track median session length, forced logout rates, and support tickets after timeout changes. Monitor anomaly challenges, concurrent session counts, and revocation events to confirm safeguards are enforced. If incidents rise or targeting increases, reduce idle time first, then tighten absolute lifetime. Re-run the calculator after major changes to roles, authentication, or data scope in production environments.
FAQs
What is the difference between idle timeout and absolute lifetime?
Idle timeout ends a session after inactivity. Absolute lifetime ends it after a fixed duration, even with activity. Using both limits exposure from unattended devices and silent token theft.
How should I set the idle warning time?
Use a short warning that helps users save work without extending risk. One to five minutes before the idle cutoff is common. Keep it consistent across similar applications.
Does enabling remember-me weaken security?
It can, because it extends persistence on shared or stolen devices. If you must support it, pair it with strong device trust, step-up checks for risky actions, and shorter absolute lifetimes.
Can stronger authentication justify longer timeouts?
Stronger factors reduce credential theft risk, but they do not eliminate session hijacking. You may allow modestly longer idle time for low-risk data, yet keep tight limits for privileged and regulated workflows.
What should I do for API access?
Prefer short-lived access tokens and rotate refresh tokens. Avoid very long-lived bearer tokens. Enforce revocation, rate limits, and anomaly detection so stolen credentials cannot be used for long.
How often should I reassess session policy?
Reassess after major auth, role, or data changes, and at least quarterly. Re-run the calculator when threats increase, incidents occur, or new controls like step-up and token rotation are introduced.