Excel LAMBDA and Dynamic Arrays: Benefits and Limits for Financial Models with Diarmuid Early

In this episode of Financial Modeler's Corner: The ModSquad, Ian Schnoor, Paul Barnhurst, and Giles Male welcome Diarmuid Early to discuss how modern Excel features are changing financial modeling. They explore the benefits of dynamic arrays, LET and LAMBDA functions, and how these tools can make financial models more flexible, consistent, and efficient.

Diarmuid Early is the Founder of Early Days Consulting and an expert in Excel and financial modeling. He is an accomplished competitive Excel esports participant and an active contributor to the Excel community. He shares practical approaches to using dynamic arrays, LET, and LAMBDA functions to build more flexible, efficient, and reliable financial models.

Expect to Learn

• How dynamic arrays improve flexibility and consistency in financial models.
• How LET and LAMBDA functions simplify complex calculations.
• Why Power Query is useful for connecting Excel workbooks.
• How custom functions can improve model accuracy and auditability.
• When modern Excel features create compatibility and modeling challenges.

• “Lambdas can do crazy things, but you don't need them to do crazy things to be useful.” - Diarmuid Early
• “For the guts of 40 years, one Excel formula returned one result, and now one Excel formula can return many results.” - Diarmuid Early

Diarmuid explains how dynamic arrays and LAMBDA functions can reduce repetitive work and help financial modelers build more adaptable models. He also highlights their limitations, particularly when dealing with circular dependencies, complex calculations, and older Excel versions.

Follow Ian:

LinkedIn - https://www.linkedin.com/in/ianschnoor/

Follow Giles:

LinkedIn - https://www.linkedin.com/in/giles-male-30643b15/

Follow Diarmuid:

LinkedIn - https://www.linkedin.com/in/diarmuidearly/

Disclosure: Portions of this episode (such as the introduction or promotional segments) use AI-generated voice narration produced under human editorial review.

In Today's Episode:

[00:00] - Introduction

[10:44] - Modern Excel & Financial Modeling

[12:41] - Understanding Dynamic Arrays

[19:15] - Understanding LAMBDA Functions

[24:35] - Practical LAMBDA Applications

[33:16] - Benefits of Reusable Functions

[34:49] - LAMBDA Limitations & Compatibility

[38:48] - Making LAMBDA Models Easier to Audit

[43:10] - When Small Model Changes Become Big Problem

[46:21] - Resources for Learning LAMBDA