---
title: 1.2 Licensing
description: "**Windows — License Tiers** PupilMetrics uses a machine-bound license on Windows. On first launch you are prompted to start a free trial or enter a license key. | Tier | Duration | Machines | |------|----------|----------| | ****Trial**** | 14 days,…"
url: "https://cnri.edu/docs/1-2-licensing/"
updated: "2026-03-27"
category: Getting Started
---

# 1.2 Licensing

**Windows — License Tiers**

PupilMetrics uses a machine-bound license on Windows. On first launch you are prompted to start a free trial or enter a license key.

| Tier | Duration | Machines |

|------|----------|----------|

| ****Trial**** | 14 days, full features | 1 |

| ****Standard**** | 1 year | 1 |

| ****Professional**** | Lifetime | 1 |

| ****Enterprise**** | Lifetime | Multiple |

****Starting the free trial****

Click ****Start Free Trial**** on the license screen. The 14-day countdown begins immediately. All features are available during the trial — no credit card required.

****Entering a license key****

1. Purchase a license key from CNRI.

2. On the license screen, paste your key into the ****License Key**** field and click ****Activate****.

3. Activation contacts `licenses.cnri.edu` to bind the key to your machine ID.

4. Once activated, PupilMetrics works offline indefinitely.

****Trial expired****

If your trial expires, the license screen appears at startup. Enter a purchased license key to restore full access.

> ****Note:**** Moving a license to a new machine requires contacting CNRI support to unbind the old machine ID.

**#### Android & iOS — In-App Purchase**

On mobile, licensing is handled through the App Store / Google Play via RevenueCat. Tap ****Subscribe**** or ****Purchase**** on the paywall screen to unlock the full app.