---
title: "MFI to melt viscosity"
category: "mfi-testing"
description: "Estimate apparent melt viscosity from melt flow index using melt density and an empirical mass-flow correlation."
url: "https://vectorbtc.com.tr/resources/calculators/mfi-viscosity/"
---

Relates mass-flow MFI to a rough viscosity order-of-magnitude for resin screening. Use capillary or rotational rheometry for process-critical viscosity data.