Interest Rate Curve - Kamino Docs

The interest rate curve shows how borrow and supply APY change as pool utilization increases from 0% to 100%, where utilization represents the share of supplied liquidity that is borrowed.

Calculate Interest Rate Curve

Generate curve points showing APY at different utilization levels.

Import Dependencies

import { createSolanaRpc, address } from '@solana/kit';
import {
  KaminoMarket,
  ONE_HUNDRED_PCT_IN_BPS,
  getBorrowRate,
  calculateAPYFromAPR,
  getCurrentLedgerInstant,
  getMedianSlotDurationInMsFromLastEpochs,
} from '@kamino-finance/klend-sdk';

Configure Market and Reserve

const marketPubkey = address('7u3HeHxYDLhnCoErrtycNokbQYbWGzLs6JSDqGAv5PfF'); // SOL/BTC Market
const reserveAddress = address('ESCkPWKHmgNE7Msf77n9yzqJd5kQVWWGy3o5Mgxhvavp'); // USDG
const CHART_POINTS = 21;

CHART_POINTS sets the chart resolution: 21 points is 0% to 100% utilization in 5% steps. The curve’s own points are always included, so its kinks aren’t skipped.

Load Market and Reserve

const rpc = createSolanaRpc('https://api.mainnet-beta.solana.com');
const market = await KaminoMarket.load(rpc, marketPubkey, await getMedianSlotDurationInMsFromLastEpochs());
const reserve = market!.getReserveByAddress(reserveAddress);

if (!reserve) {
  console.log('Reserve not found:', reserveAddress);
}

Extract Borrow Curve Points

The curve is a list of (utilization, borrow rate) points in basis points, joined by straight lines. Its rates are APRs. The on-chain list has a fixed length, so repeated points at 100% are padding and are dropped.

const curve: [number, number][] = reserve!.state.config.borrowRateCurve.points
  .filter((point, index, points) => index === 0 || point.utilizationRateBps !== points[index - 1].utilizationRateBps)
  .map((point) => [point.utilizationRateBps / ONE_HUNDRED_PCT_IN_BPS, point.borrowRateBps / ONE_HUNDRED_PCT_IN_BPS]);

console.log('Curve points (utilization, borrow APR):', curve);

The reserve metrics history endpoint returns the same configured curve as borrowCurve, without an RPC.

Read the Rate Parameters

const rateFactor = reserve!.rateAdjustmentFactor();
const hostRate = reserve!.getFixedHostInterestRate().toNumber() * rateFactor;
const supplyShare = 1 - reserve!.state.config.protocolTakeRatePct / 100;

Borrowers pay the curve rate plus the reserve’s fixed host interest. Suppliers earn the curve rate on the borrowed share of the reserve, minus the protocol take rate.

Generate Curve Points

Calculate the borrow and supply APY at each utilization.

const utilizations = [
  ...new Set([...Array.from({ length: CHART_POINTS }, (_, i) => i / (CHART_POINTS - 1)), ...curve.map(([u]) => u)]),
].sort((a, b) => a - b);

const curvePoints = utilizations.map((utilization) => {
  const borrowRate = getBorrowRate(utilization, curve) * rateFactor;
  return {
    utilization: `${(utilization * 100).toFixed(0)}%`,
    borrowAPY: `${(calculateAPYFromAPR(borrowRate + hostRate) * 100).toFixed(2)}%`,
    supplyAPY: `${(calculateAPYFromAPR(utilization * borrowRate * supplyShare) * 100).toFixed(2)}%`,
  };
});

console.table(curvePoints);

getBorrowRate reads the borrow rate at any utilization from the curve. calculateAPYFromAPR compounds an APR into an APY.

Compare with Current Rates

const ledgerInstant = await getCurrentLedgerInstant(rpc);

console.log({
  symbol: reserve!.getTokenSymbol(),
  utilization: `${(reserve!.calculateUtilizationRatio() * 100).toFixed(2)}%`,
  borrowAPY: `${(reserve!.totalBorrowAPY(ledgerInstant) * 100).toFixed(2)}%`,
  supplyAPY: `${(reserve!.totalSupplyAPY(ledgerInstant) * 100).toFixed(2)}%`,
});

The table shows the borrow and supply APY across the curve, and the current rates show where the reserve sits on it. Plot the table with any charting library.

Understanding the Results

The curve shows how rates change with utilization:

Below the kink: rates rise slowly. For USDG the kink is at 95% utilization.
Above the kink: rates rise sharply to pull in deposits and push borrowers to repay.
Supply APY: always below borrow APY, because suppliers earn only on the borrowed share of the reserve, minus the protocol take rate.

Example Output

USDG on the SOL/BTC Market, October 2026 (rows trimmed):

Curve points (utilization, borrow APR): [ [ 0, 0 ], [ 0.95, 0.0551 ], [ 1, 0.3634 ] ]

utilization  borrowAPY  supplyAPY
0%           0.50%      0.00%
25%          1.97%      0.33%
50%          3.46%      1.31%
75%          4.97%      2.98%
90%          5.89%      4.32%
95%          6.19%      4.82%
100%         44.54%     38.69%

{ symbol: 'USDG', utilization: '90.61%', borrowAPY: '5.92%', supplyAPY: '4.38%' }

​Calculate Interest Rate Curve

​Import Dependencies

​Configure Market and Reserve

​Load Market and Reserve

​Extract Borrow Curve Points

​Read the Rate Parameters

​Generate Curve Points

​Compare with Current Rates

​Understanding the Results

​Example Output

Calculate Interest Rate Curve

Import Dependencies

Configure Market and Reserve

Load Market and Reserve

Extract Borrow Curve Points

Read the Rate Parameters

Generate Curve Points

Compare with Current Rates

Understanding the Results

Example Output