# burn_increase_mult (/docs/hyperparameters/burn-increase-mult)

Controls how sharply the registration price reacts to demand: every successful
registration multiplies the current burn cost by this factor. Owners tune it to
decide how strongly a registration burst should price out the next entrant;
miners see it as the reason the cost quoted a moment ago can jump before their
own transaction lands.

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

After each successful registration, `bump_registration_price_after_registration`
(in `pallets/subtensor/src/subnets/registration.rs`) sets

```
new_burn = clamp(burn × burn_increase_mult, min_burn, max_burn)
```

The bump is immediate — the very next registration, even in the same block,
pays the raised price. Values below 1 are treated as 1 at read time
(`max(mult, 1)`), so the multiplier can never shrink the price. Between
registrations, the per-block decay governed by
[`burn_half_life`](/docs/hyperparameters/burn-half-life) pulls the price back
toward [`min_burn`](/docs/hyperparameters/min-burn). The steady-state
registration rate the pair supports is where bumps and decay cancel:
`half_life × log2(mult)` blocks per registration.

The value is stored in `BurnIncreaseMult` as U64F64 fixed-point (raw bits
divided by 2^64 give the real multiplier); the default is **1.26** (\~3
registrations to double the price). The owner-set extrinsic
(`sudo_set_burn_increase_mult` in `pallets/admin-utils/src/lib.rs`) requires
the value to be **between 1 and 3** inclusive and rejects the root subnet,
which does not use the bump path.

<HyperparamBurnController focus="burn_increase_mult" />

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

```bash
btcli sudo get --netuid 12 --name burn_increase_mult
btcli sudo set --netuid 12 --name burn_increase_mult --value 1.5
```

Settable by the subnet owner or root. A value with a decimal point is the
multiplier itself (`1.5`); a plain integer is the raw U64F64 bits.

## Related [#related]

* [`burn_half_life`](/docs/hyperparameters/burn-half-life) — the decay that
  counteracts these bumps
* [`min_burn`](/docs/hyperparameters/min-burn) /
  [`max_burn`](/docs/hyperparameters/max-burn) — the clamp bounds
* [`max_regs_per_block`](/docs/hyperparameters/max-regs-per-block) — the hard
  per-block cap behind the price mechanism