> ## Documentation Index
>
> Fetch the complete documentation index at: https://lithi.ai/llms.txt
>
> Use this file to discover all available pages before exploring further.

# Your Mac’s energy use and impact

Your Mac records how long it works for Lithi, plus any energy readings it can give. Lithi uses these to build the **Monthly Compute impact report**, and doesn’t need customer task content or unrelated personal information to do it.

## What your Mac records while it works

When a task runs, your Mac records the time it worked and any available energy readings. Before a task starts, Lithi checks that your Mac is allowed and able to run it.

A task doesn’t have to succeed to use electricity. A failed attempt, a retry and a separate result check all count toward energy, even when the result is rejected. A task rejected before it starts doesn’t count as a run. Electricity used by those pre-start checks is recorded separately.

## How sure each number is

Not every Mac measures the electricity each task uses. A timing, temperature or power-state reading can be real without showing how much electricity was used. When a reading can’t support an electricity figure, that figure stays unavailable. It never turns into zero.

Each figure in the report carries one of these labels:

| Label | How it was measured |
|---|---|
| **Meter reading** | A meter measured the electricity, with a clear record of what it covered. |
| **Calibrated Mac reading** | Your Mac’s own reading, checked against a suitable meter and used only within the limits that check proved. |
| **Calibrated estimate** | An estimate from records of how the work ran, using a versioned energy profile. |
| **Uncalibrated reading** | A signal that isn’t enough on its own to report an electricity figure. |
| **No usable measurement** | Not enough to measure. This doesn’t mean no electricity was used. |

## What Lithi never needs

The impact report doesn’t need your exact home address, a list of your apps or running programs, the contents of customer tasks, or another person’s account details.

Your Mac can still read the piece of work it’s assigned while it processes it. Encryption and local preparation limit what leaves the customer’s machine, and Lithi caps how much one Mac owner can receive, but neither makes the work unreadable to your Mac. [How Lithi uses encryption](/trust/encryption) explains the boundary.

Energy readings are also separate from your earnings. A reading doesn’t show what you’ve earned or whether you’ve been paid.

## Counting electricity once

One reading can cover several tasks, so Lithi splits it across the work it covers. When a reading already includes your Mac’s own use, Lithi doesn’t add your Mac’s figure on top.

## Your electricity region

Lithi turns electricity into emissions using a factor for a broad electricity-grid region. It uses the region that matches the measurement, not your exact address. If the region, the emissions factor or the energy checks are missing, that figure stays unavailable.

The [calculation guide](/trust/impact) shows how each figure is worked out, [Read a Compute impact report](/docs/compute/impact-report) explains the customer’s report, and the [Lithi Compute paper](/papers/compute) explains how the system works.