# How to calculate revenue doubling time startup founders skip

> Startup founders skip revenue doubling time calculations until VCs ask.
- Title: How to calculate revenue doubling time startup founders skip
- Summary: Startup founders skip revenue doubling time calculations until VCs ask. Founders use monthly growth rates without calculating doubling time, risking…
- Keywords: revenue doubling time, monthly growth rate, rule of 72, startup growth, y combinator, paul graham, term sheet clauses, liquidation preference, board composition, protective provisions, Startup Fortune
- Source: Startup Fortune — https://startupfortune.com/how-to-calculate-revenue-doubling-time-startup-founders-skip-until-a-vc-asks
- Published: 2026-11-09T05:07:06+00:00
- Read time: 1 min
- Topics: revenue doubling time, monthly growth rate, rule of 72, startup growth, y combinator, paul graham, term sheet clauses, liquidation preference, board composition, protective provisions, startups, business
## What founders skip
Founders quote growth as a percentage but hide how fast revenue actually doubles.
## The formula
Months to double equals natural log of 2 divided by natural log of one plus monthly growth rate.
## The quick check
Divide 72 by monthly growth rate to estimate doubling time in months.
## Why 72 not 69.3
72 splits evenly by 2 3 4 6 8 9 and 12 for mental arithmetic.
## Growth rate accuracy
Use three months of net revenue with RRI function not best month or annual figure divided by 12.
## Example calculation
Monthly revenue $30,000 to $37,800 in three months equals 8% monthly growth.
## Growth impact
Halving monthly growth from 8% to 4% stretches doubling time from 9.0 to 17.7 months.
## Long-term effect
After two years 8% monthly growth multiplies revenue by 6.3 versus 2.6 for 4%.
## Rule of 72 drifts
At 20% monthly growth rule says 3.6 months but true figure is 3.8 months.
## Units matter
Annual growth rates must not be divided by 12 to get monthly rates.
## Paul Graham's benchmark
Y Combinator companies need 5% to 7% weekly growth for healthy doubling time.
## What to say to investors
Lead with trailing three-month compound rate and doubling time for clarity.
## Investor perspective
Doubling time stretches as revenue base grows, showing healthy growth trends.
## What happens next
Founders should calculate doubling time using three months of net revenue data.
## Key takeaway

Founders use monthly growth rates without calculating doubling time, risking misrepresentation of revenue growth potential.