# activity_cutoff_factor (/docs/hyperparameters/activity-cutoff-factor)

`activity_cutoff_factor` sets the inactivity window as a fraction of the
epoch length instead of an absolute block count: the effective
[`activity_cutoff`](/docs/hyperparameters/activity-cutoff) is
`factor × tempo / 1000` blocks. Because the window scales with
[`tempo`](/docs/hyperparameters/tempo), a subnet that changes its epoch
cadence keeps the same *number of epochs* of tolerance rather than a fixed
wall-clock window.

## How it works [#how-it-works]

`get_activity_cutoff_blocks` (`pallets/subtensor/src/utils/misc.rs`) computes
`factor_milli × tempo / 1000`, clamped to at least 1 block, and the epoch uses
that value to mask inactive validators out of consensus (see
[`activity_cutoff`](/docs/hyperparameters/activity-cutoff) for the masking
mechanics).

The factor is per-mille: 1,000 means one full tempo, 13,889 (the default)
means \~13.9 tempos — 5,000 blocks (\~16.7 hours) at the default tempo of 360,
matching the legacy absolute cutoff. Bounds are 1,000–50,000 (one to fifty
tempos).

## Reading and setting [#reading-and-setting]

Inspect with:

```
btcli sudo get --netuid N --name activity_cutoff_factor
```

Owner-settable:

```
btcli sudo set --netuid N --name activity_cutoff_factor --value 13889
```

This dispatches `sudo_set_activity_cutoff_factor` (AdminUtils), owner-or-root:
the owner path is rate-limited (once per \~2 tempos by default) and respects
the admin freeze window; root bypasses both. It supersedes the legacy
absolute-blocks `sudo_set_activity_cutoff`, whose stored value the epoch
ignores.

## Related [#related]

[`activity_cutoff`](/docs/hyperparameters/activity-cutoff) ·
[`tempo`](/docs/hyperparameters/tempo) ·
[`kappa`](/docs/hyperparameters/kappa) ·
[`max_validators`](/docs/hyperparameters/max-validators) ·
[`weights_rate_limit`](/docs/hyperparameters/weights-rate-limit)