Fundraising Fox
🦊/Companies
Sign in

Napkin Math

YC X26

San Francisco, US · Founded 2026 · 3 employees · 1 known investors

Find your way into Napkin Math

865 people in our graph share verified history with the Napkin Math team — schools, employers, funds. One of them is your warm intro.

Mike Volpiunlockedknows Manuel Castro · together at Sonos, Inc. (overlapped)
×3knows the team · via Verkada
knows the team · via Samsara
×3knows the team · via Massachusetts Institute of Technology
×2knows the team · via Sonos, Inc.
knows the team · via MIT Lincoln Laboratory

An AI-powered food journal application that personalizes nutrition guidance based on individual health goals and lifestyle constraints rather than generic calorie-tracking recommendations.

Also known as Paper Star

ConsumerUnited States of AmericaAmerica / Canada

Founders & leadership· Y Combinator alumni (X26)

Napkin Math was founded in 2026 by Jynnie Tang, Manuel Castro, and Claire Nord.

JTJynnie Tang
Jynnie Tangin𝕏Co-FounderJynnie Tang previously worked at Retool and One More Multiverse, and studied at MIT. She is now building Napkin Math, an AI-powered food journal application.
MCManuel Castro
Manuel Castroin𝕏Co-FounderManuel Castro previously worked at Sonos, a healthcare technology company, and Verkada before founding Napkin Math, an AI-powered food journal application.
CNClaire Nord
Claire Nordin𝕏Co-FounderClaire Nord previously worked on OS security at Apple and as an engineer at Samsara, and holds a degree in Computer Science from MIT (2019). She is currently building Napkin Math, an AI-powered food journal application.

Investors · 1

Y CombinatorSan Francisco · $500K

Images

Napkin Math photo

Competitors · 1

by search overlap
Every5 shared keywordsEvery is a media and subscription publication offering essays and columns—such as Katie Parrott's "Working Overtime"—about how AI is changing work and careers. It provides daily insights and early access to AI tools for a subscriber audience of leaders, builders, and innovators.

Companies competing with Napkin Math for the same Google search keywords, organic and paid, via search-intersection analysis.

In the news

Napkin Math - hyper-personalized AI food journalycombinator.com · May 2026OpenAI Is a Once-in-a-lifetime Startupevery.to · Apr 2025Napkin Math: A Quick Way to Estimate Feasibility, Cost, and Impactimpact.ac4d.com · Mar 2025Closure | Paper Napkin Math for Evaluating Startup Opportunitiesdadrian.io · Aug 2022

Frequently asked questions

What does Napkin Math do?
An AI-powered food journal application that personalizes nutrition guidance based on individual health goals and lifestyle constraints rather than generic calorie-tracking recommendations.
Who founded Napkin Math?
Napkin Math was founded by Jynnie Tang, Manuel Castro, Claire Nord in 2026.
Who are Napkin Math's investors?
Napkin Math's investors include Y Combinator.
Where is Napkin Math headquartered?
Napkin Math is headquartered in San Francisco, US.