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Knowledge Base
Answers to the questions every founder Googles at 2am.
How do I validate a startup idea?
Step-by-step framework
Read answer →What is TAM, SAM, and SOM?
Market sizing explained
Read answer →How do I get my first customers?
Proven early-traction tactics
Read answer →Why do most startups fail?
Top reasons & how to avoid them
Read answer →What is product-market fit?
How to know when you have it
Read answer →How do I write a pitch deck?
The 10 slides investors expect
Read answer →Free Tools
Quick tools to size your market, project runway, and check unit economics — no signup needed.
Market Size
TAM / SAM / SOM
How big is your market really? Estimate all three tiers in 30 seconds.
Try calculator →Startup Runway
Cash & Burn
Know exactly how many months you have before you need to raise or break even.
Try calculator →CAC vs LTV
Unit Economics
Are your unit economics healthy? Find out if your business model actually works.
Try calculator →ROI Calculator
Returns & Profit
Is your investment paying off? See your return on investment and payback period instantly.
Try calculator →Break-Even Point
Fixed vs Variable Costs
How many sales before you start profiting? Find out in seconds.
Try calculator →Startup Cost Estimator
Budget & Funding Needs
Estimate your first-year costs and minimum funding needed to launch and operate.
Try calculator →Real Evaluations
We ran all 10 Y Combinator Spring 2026 “Request for Startups” ideas through IdeaCheck. Here are three results.
Modern Metal Mills
by Zane Hengsperger
Massive domestic market, strong timing with reshoring push — but distribution into heavy industry is the hard part.
AI Guidance for Physical Work
by David Lieb
Skilled labor shortage is real and urgent. Timing is excellent. HN community sees this as one of the most fundable hardware + AI plays.
AI-Native Hedge Funds
by Charlie Holtz
Monumental regulatory and distribution hurdles. HN community was consistently skeptical of similar ideas over the past 5 years.
Got Questions?
Everything founders ask before validating their first idea.