B2B Startup Metrics | Startup School Summary

Today I'll summarize the talk on B2B startup core metrics by Tom Blomfield, Group Partner at Y Combinator. The talk covers the metrics every startup must know for successful growth and how to use them. Tom emphasizes the importance of metrics through his experience and concrete examples, providing practical advice.

1. Why Do Metrics Matter?

• Metrics are a startup's compass Metrics are tools that help startups make the right decisions. Tom compares them to an aircraft's instruments, saying "Running a startup without metrics is like flying a plane without instruments."

  "Having great metrics is like having great instruments in an aircraft. It lets you tweak and iterate and make sure you're really in control of your startup."

• It's too late to set up metrics after launching Many founders try to set metrics only after launching, but that's the wrong approach. Basic metrics must be prepared before launch.

  "You should build basic metrics into a product before you launch."

• Metric balance matters Trying to track too many metrics is also a problem. Early startups don't have enough data, so focusing on 4–5 key metrics is important.

  "Pick four or five key metrics to track accurately, not 30 or 50."

2. Things to Watch Out for When Setting Metrics

• Clearly define metrics and align with your team Unclear metric definitions cause unnecessary team arguments. For example, the entire team should agree on and consistently maintain the definition of "active user."

  "Constant arguments about what your key metrics are are even worse than having no metrics at all."

• Don't change your metrics Changing definitions because metrics don't meet expectations is self-deception.

  "Honestly, you're only fooling yourself in this situation."

• Avoid vanity metrics Don't get fixated on metrics that look big on the surface but aren't tied to actual success — page views, GMV, etc.

  "Vanity metrics are numbers that seem really big and perhaps they keep increasing, but they're not actually tied to the success of your company."

3. Core Metrics: What Should You Track?

1) Revenue

• For most B2B startups, the most important metric is revenue.
• Even if revenue is low, don't hide it — be honest about it.

  "If you're ashamed of this number, you hide it away, it's easy to kid yourself."

2) Burn Rate and Runway

• Burn Rate: Monthly expenses minus revenue.
• Runway: How much longer you can operate with current funds.

  "If your burn rate is $100,000 a month and you have $1 million in the bank, you have 10 months of runway."

3) Retention

• Indicates how long customers continue to use and pay for the product.
• Track monthly customer retention through cohort analysis and visualize it to identify problems.

  "If your customers all churn out, you're scrambling to fill up a leaky bucket."

4) Net Dollar Retention

• A metric that checks whether existing customer revenue grows over time.
• Above 100% means your existing customer base is growing.

  "Net dollar retention above 100% means your cohorts are growing over time."

5) Gross Margin

• Revenue minus variable costs per customer.
• For AI startups, model usage costs from services like OpenAI are a major variable cost.

  "For AI companies today, the gross margin is a really important cost."

4. Startup Operational Strategy Using Metrics

• Advantages of high-retention businesses High-retention businesses build a stable revenue base over time. Tom compares this to a "layer cake" — revenue layers stacking up.

  "If your retention flattens out, you build up this layer cake of revenue over time."

• The danger of negative gross margin While losses may be acceptable early on, the business must eventually transition to a profitable structure.

  "If you start with negative unit economics, you really have to have a plan to fix them."

• Focus on real metrics instead of vanity metrics GMV, page views, etc. may look good but may have nothing to do with actual business success.

  "Track the right metrics. Don't fall for vanity metrics like gross merchandise value or impressions."

5. Closing Advice

• Prepare metrics before launch Starting without metrics is dangerous.

  "Don't launch without metrics in place. It's like flying blind."

• Don't forget to talk to customers Metrics alone can't drive every decision. Have direct conversations with customers and get product feedback.

  "You still have to get out of the building and talk to customers."

• Balance metrics, customer conversations, and intuition Successful startup operations require a balance of metrics, customer communication, and product intuition.

  "Run your startup with the right blend of metrics, talking to customers, and product intuition."

6. Key Terms

• Revenue
• Burn Rate
• Runway
• Retention
• Net Dollar Retention
• Gross Margin
• Vanity Metrics
• Cohort Analysis

This talk provides tremendous help for startups to set the right metrics and build growth strategies based on them. Following Tom's advice, may your startup head in a successful direction