# Espresso SRB

ESPSRB is a benchmark representing the mean, annualized staking rate across all active Espresso validators.

ESPSRB is calculated and published by Staking Rewards via the [Espresso Profile](https://www.stakingrewards.com/asset/espresso) and [Data API](https://www.stakingrewards.com/data-api).

> **TL;DR:** Espresso staking rewards follow a dynamic formula where the rate decreases as staking participation increases: 0.03 / sqrt(2 \* participation). At 1% participation the rate is \~21%, at 50% it is 3%, and at 100% it is \~2.1%.

### ESP Staking Rewards Rate: ESPSRB

$$
ESPSRB = 0.03 / \sqrt{2 \cdot \max(p, 0.01)}
$$

<table><thead><tr><th width="149">Formula key</th><th width="180">Metric name</th><th>Description</th></tr></thead><tbody><tr><td>p</td><td>Staking Participation</td><td>The ratio of total staked ESP tokens to total supply (staked_tokens / total_supply).</td></tr><tr><td>0.03</td><td>Protocol Constant</td><td>A fixed parameter defined by the Espresso protocol that governs the base reward emission rate.</td></tr><tr><td>0.01</td><td>Participation Floor</td><td>A minimum threshold for staking participation that prevents the formula from diverging at near-zero participation levels.</td></tr></tbody></table>

* ESPSRB is non-compounded, excluding returns from reinvestment of rewards.
* ESPSRB includes both claimed and unclaimed rewards.
* The reward rate is dynamic: it decreases as staking participation increases. At 1% participation the rate is approximately 21.21%, at 50% it is 3.00%, and at 100% it is approximately 2.12%.

#### Slashing

* ESPSRB does not factor in the possibility of slashing occurrences.
* Espresso implements slashing for validator misbehavior, but slashed tokens are not accounted for in the benchmark calculation.

***

### ESP Validator Staking Reward Rate: ESPSRB(v)

Staking Rewards calculates the ESPSRB for each validator based on their individual commission rate and vote participation performance.

$$
ESPSRB(v) = ESPSRB \* (1 - c) \* perf
$$

<table><thead><tr><th width="149">Formula key</th><th width="180">Metric name</th><th>Description</th></tr></thead><tbody><tr><td>c</td><td>Commission</td><td>The fee imposed by a specific validator to its delegators, expressed in basis points where 10000 = 100%. Converted to a decimal (commission / 10000) for the formula.</td></tr><tr><td>perf</td><td>Performance</td><td>The validator's vote participation rate, ranging from 0.0 to 1.0. Determined by the proportion of consensus votes the validator successfully participates in during the current epoch.</td></tr></tbody></table>

***

#### Observation Period:

1. The ESPSRB is determined based on the current staking participation rate and total supply at the point of evaluation.
2. This data is then annualized for a comprehensive year-long projection.

#### Calculation

The calculation happens every 6 hours and is immediately published via [Data API](https://www.stakingrewards.com/data-api).

#### Limitations

1. ESPSRB employs a 365-day convention for annualizing staking rewards. This convention remains consistent and does not accommodate adjustments for leap years.
2. ESPSRB does not factor in slashing occurrences.
3. ESPSRB excludes rewards accrued from on-chain transaction fees.
4. The participation floor at p = 0.01 (1%) prevents formula divergence at near-zero staking participation but means the rate is capped at approximately 21.21% regardless of how low actual participation falls below 1%.
5. No guarantee that individual validator rates will match ESPSRB(v) exactly due to variations in vote participation across epochs.

***

### ESP Real Reward Rate: ESPSRB^R

The real reward rate calculates the ESPSRB adjusted for inflation in the network.

$$
ESPSRB^R = (1 + ESPSRB) / (1 + ir) - 1
$$

<table><thead><tr><th width="149">Formula key</th><th width="180">Metric name</th><th>Description</th></tr></thead><tbody><tr><td>ir</td><td>Inflation Rate</td><td>The annual rate of new token issuance relative to total supply, calculated as staking_ratio * reward_rate.</td></tr></tbody></table>

**Inflation Rate Behavior**

* Espresso's inflation is dynamic and directly tied to the staking participation rate. The annual inflation is computed as the product of the staking ratio and the reward rate: `inflation = p * R(p)` where `R(p) = 0.03 / sqrt(2 * max(p, 0.01))`. As staking participation increases, the per-token reward rate decreases, but the total inflation increases because more tokens are earning rewards. At 100% staking participation, inflation reaches approximately 2.12%. At the current participation level of approximately 26%, inflation is approximately 1.09%.

***

### Other Espresso metrics calculated by Staking Rewards:

<table><thead><tr><th width="190">Metric</th><th>Description</th></tr></thead><tbody><tr><td>Delegated Tokens</td><td>The number of ESP tokens delegated to validators by external delegators.</td></tr><tr><td>Self Staked Tokens</td><td>The number of ESP tokens staked by validators to their own node, detected when a validator's Ethereum address appears in their own delegator set.</td></tr><tr><td>Staking Wallets</td><td>The total number of delegator entries across all validators on-chain.</td></tr><tr><td>Active Validators</td><td>The number of validators currently active in the stake table for the current epoch.</td></tr></tbody></table>

***

#### Data Sources:

* Espresso Network Query Service for stake table, validator data, vote participation, block rewards, and total minted supply
* CoinGecko for price and circulating supply data

***

#### References:

* [Espresso Staking Rewards Calculation](https://docs.espressosys.com/network/concepts/the-espresso-network/internal-functionality/stake-table/staking-rewards-calculation)
* [Espresso Network Documentation](https://docs.espressosys.com/)

***

:books: [Learn more about ESP Staking](https://www.stakingrewards.com/asset/espresso)

:bar\_chart: [Calculate your ESP Staking Rewards](https://www.stakingrewards.com/calculator?asset=espresso)

:gear: [Access historic Espresso Staking Data via API](https://www.stakingrewards.com/data-api)

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Last updated on 03/27/2026
```


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