# Polkadot SRB

DOTSRB is a benchmark representing the annualized staking rate for the DOT token.

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

> **TL;DR:** Polkadot staking rewards are derived from actual on-chain era rewards, not inflation estimates. The reward rate equals era validator rewards annualized over 365 days divided by total staked DOT. Validator-level rates are adjusted by commission using the era-based Nominated Proof of Stake model.

### DOT Staking Rewards Rate: DOTSRB

$$
DOTSRB = evr \* t\_y / st
$$

<table><thead><tr><th width="145">Formula Key</th><th width="169">Metric Name</th><th>Description</th></tr></thead><tbody><tr><td>evr</td><td>Era Validator Reward</td><td>The total reward distributed to all validators for the previous era, sourced directly from on-chain storage.</td></tr><tr><td>st</td><td>Staked Tokens</td><td>The total staked DOT in the active era, sourced from on-chain era total stake.</td></tr><tr><td><span class="math">t_y</span></td><td>Year Constant</td><td>365d — used to annualize the per-era reward.</td></tr></tbody></table>

* DOTSRB is non-compounded, excluding returns from reinvestment of rewards.
* The reward rate is derived from actual on-chain era rewards, not from an inflation model estimate.

***

### DOT Validator Staking Rewards Rate: DOTSRB(v)

Staking Rewards calculates the DOTSRB for each validator based on their individual commission rate.

$$
DOTSRB(v) = DOTSRB \* (1 - c)
$$

<table><thead><tr><th width="149">Formula key</th><th width="216">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.</td></tr></tbody></table>

***

#### Observation Period:

1. The DOTSRB is determined based on the latest completed era at the evaluation point.
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. DOTSRB employs a 365-day convention for annualizing era reward data. This convention remains consistent and does not accommodate adjustments for leap years.

***

### DOT Real Reward Rate: DOTSRB^R

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

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

<table><thead><tr><th width="147">Formula key</th><th width="148">Metric name</th><th>Description</th></tr></thead><tbody><tr><td>ir</td><td>Inflation Rate</td><td>Derived from on-chain era rewards: <code>eraValidatorReward * 365 / totalSupply</code>.</td></tr></tbody></table>

**Inflation Rate Behavior**

* Since March 2026, Polkadot has a capped supply model with a maximum of 2.1 billion DOT. The emission follows a stepped curve that reduces approximately every 2 years, starting at roughly 13.14% of the remaining supply per step. This replaced the previous fixed 120M DOT/year expansion model. The inflation rate is derived from actual on-chain era rewards, making it self-correcting as the emission schedule progresses.

***

### Other Polkadot metrics calculated by Staking Rewards:

<table><thead><tr><th width="212.99999999999994">Metric</th><th>Description</th></tr></thead><tbody><tr><td>Delegated Tokens</td><td>The number of DOT tokens delegated to validators (nominators' stake).</td></tr><tr><td>Self Staked Tokens</td><td>The number of DOT tokens staked by validators directly (stash bonded amount).</td></tr><tr><td>Staking Wallets</td><td>Total number of nominators on-chain.</td></tr></tbody></table>

***

Data Sources:

* Polkadot Substrate RPC (on-chain staking pallet queries via py-substrate-interface)
* CoinGecko for price and circulating supply

***

#### References:

* [Polkadot Staking Docs](https://wiki.polkadot.network/docs/learn-staking)

***

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

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

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

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Last updated on 03/16/2026
```


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