TL;DR
How Many Piano Tuners in Chicago?: A canonical quantitative trading interview question at foundation difficulty. Commonly asked at Jane Street, Optiver, SIG, Akuna Capital, IMC.
By Valenke Exam Prep Team·Last updated 2026-06-01
foundationFermi Estimation
How Many Piano Tuners in Chicago?
Asked at: Jane Street, Optiver, SIG, Akuna Capital, IMC
Problem
Estimate the number of piano tuners in Chicago. Show your reasoning step by step.
This is the most famous Fermi estimation question, attributed to Enrico Fermi himself.
Ready to practice for the Valenke Finance Exam?
Adaptive practice powered by Item Response Theory targets your weak areas. Start with 3 free sessions.
Start free practice →