RUNWAY
CALCULATOR
Estimate startup and personal runway with your own assumptions.
Include income, expenses, reserves and buffers. Then compare a less optimistic scenario before making the next commitment.
About 5 minutes. Free. No signup.
Just need a quick cash calculation?
Start with three numbers
Quick cash runway
A hypothetical example to replace with your own figures. Net monthly burn means all spendable income has already been subtracted from all expenses and tax reserves. Keep every amount in one currency.
6.7 months
$20,000 available ÷ $3,000 monthly net burn.
Constant cash and burn only; excludes future funding, timing changes and recovery. Zero burn means costs are covered under your assumptions, not permanent safety. For insurance, childcare, tax assumptions and scenario comparisons, close this quick calculation and choose the guided calculator above. Quick inputs stay local and do not replace your saved detailed progress.
Hypothetical example
A worked example with additional costs
The simple math
$100K ÷ $7K/month = 14 months
+$550
Health insurance
+$420
Annual-cost reserve
+$400
Quarterly surprises
-$21K
Emergency buffer
The adjusted example
9 months
36% less than the cash-only estimate
What You'll Get
Build a first estimate of your financial runway:
Find What You Forgot
Include insurance, your chosen tax reserve, annual expenses and a surprise buffer.
Cash-Only vs Adjusted Scenario
Compare a cash-only estimate with a scenario that includes your income and selected reserves.
Decision Timeline
See illustrative checkpoints alongside the hard deadlines you enter.
Scenario Notes
Rule-based prompts based on your inputs. Review them against your actual obligations.
How It Works
Five screens to clarity:
Quick Setup
Country, situation, and who depends on your income. Sets editable example defaults.
Your Numbers
Cash available, incoming funds, income (if any), and monthly expenses.
What You Forgot
Review insurance, tax reserves, annual costs and a chosen surprise buffer.
Your Limits
Emergency buffer, 'oh shit' number, and any hard deadlines (visa, lease, partner timeline).
Risk Profile
How accurate is your tracking? What's your risk tolerance? This adjusts everything.
Your Results Include
- Cash-only and adjusted scenario comparison— under visible assumptions
- Itemized forgotten expenses— using your amounts
- Decision timeline with dates— illustrative checkpoints
- Best/worst/bridge scenarios— compare selected changes
- Rule-based scenario notes— specific to your situation
Why the assumptions matter
Monthly totals can hide obligations that arrive later. A reserve, an annual bill or a delayed customer payment can change the decision you need to make.
This calculator makes the inputs visible. Use the result as a scenario, check the cash timing separately, and keep a record of the assumptions you change.
Read the runway guide and worksheet
George Pu
Founder Reality · free founder resources
Frequently Asked Questions
Takes 5 minutes. Free forever. No login required to see your results.
Put the result in context
A number is the beginning of the decision.
How to calculate startup runway without hiding the assumptions
Calculate cash runway, distinguish gross from net burn, and stress-test customer payments and founder expenses.
Read the guide and use the worksheet →From the field
Personal accounts behind the questions. Each essay reflects when it was written.
What a 3-Person Team Actually Pays for AI: July 2026
In the first week of July I spent over $5,000 coding through one company's API and couldn't tell you what I got for it. Here's what we actually pay now -…
Why this reading: Read the reported AI bill as an operating-cost account. Its missing reporting window and task measurements prevent a cost-per-result comparison.
I'm Done Pretending I Know My Net Worth
George’s February account of removing a paper valuation from his profile and focusing on cash flow and expenses.
Why this reading: Use this account of a paper valuation to distinguish a headline asset value from cash available for obligations.
I'm Starting to Write About Money
George’s April introduction to writing about financial products, personal choices and the numbers behind them.
Why this reading: Read this for the author's reasons for discussing money, then keep personal financial choices separate from your company cash forecast.