diff --git a/sdk/src/index.ts b/sdk/src/index.ts
index 802fc9d6..0a43257b 100644
--- a/sdk/src/index.ts
+++ b/sdk/src/index.ts
@@ -16,6 +16,7 @@ export * from './clearingHouseUser';
 export * from './clearingHouse';
 export * from './factory/clearingHouse';
 export * from './factory/clearingHouseUser';
+export * from './math/collateral';
 export * from './math/conversion';
 export * from './math/funding';
 export * from './math/insuranceFund';
diff --git a/sdk/src/math/collateral.ts b/sdk/src/math/collateral.ts
new file mode 100644
index 00000000..b480d0cb
--- /dev/null
+++ b/sdk/src/math/collateral.ts
@@ -0,0 +1,27 @@
+import { MarketsAccount, StateAccount } from '../types';
+import { Connection } from '@solana/web3.js';
+
+/**
+ * Client collateral is represented by the balance of the collateral wallet, as specified in the state, minus the sum of
+ * each markets undistributed fees.
+ *
+ * @param connection
+ * @param state
+ * @param marketsAccount
+ * @returns Precision : QUOTE_ASSET_PRECISION
+ */
+export async function calculateUserCollateralSize(
+	connection: Connection,
+	state: StateAccount,
+	marketsAccount: MarketsAccount
+): Promise<BN> {
+	const collateralVaultPublicKey = state.collateralVault;
+	const collateralVaultAmount = new BN(
+		(
+			await connection.getTokenAccountBalance(collateralVaultPublicKey)
+		).value.amount
+	);
+	return marketsAccount.markets.reduce((collateralVaultAmount, market) => {
+		return collateralVaultAmount.sub(market.amm.totalFee);
+	}, collateralVaultAmount);
+}