Total value locked (TVL) is widely used to measure the size and popularity of decentralized finance (DeFi). However, TVL can be manipulated and inflated through “double counting” activities such as wrapping and leveraging. As existing methodologies addressing double counting are inconsistent and flawed, we propose a new framework, termed “total value redeemable (TVR)”, to assess the true underlying value of DeFi. Our formal analysis reveals how DeFi’s complex network spreads financial contagion via derivative tokens, increasing TVL’s sensitivity to external shocks. To quantify double counting, we construct the DeFi multiplier, which mirrors the money multiplier in traditional finance (TradFi). Our measurements reveal substantial double counting in DeFi, finding that the gap between TVL and TVR reached $139.87 billion during the peak of DeFi activity on December 2, 2021, with a TVL-to-TVR ratio of approximately 2. We conduct sensitivity tests to evaluate the stability of TVL compared to TVR, demonstrating the former’s significantly higher level of instability than the latter, especially during market downturns: a 25% decline in the price of Ether (ETH) leads to a $1 billion greater decrease in TVL compared to TVR among leading protocols via asset value depreciation and liquidations triggered by derivative tokens. We also document that the DeFi money multiplier is positively correlated with crypto market indicators and negatively correlated with macroeconomic indicators. Overall, our study suggests that TVR is more reliable and stable than TVL.