PureBuild is a collection of free, deterministic calculators designed for startup founders and builders. Our tools help you make data-driven decisions about equity, dilution, runway, unit economics, and more.

Are PureBuild tools really free?

Yes, all PureBuild tools are completely free to use. No sign-up required, no hidden fees, no premium tiers. We believe essential business calculations should be accessible to everyone.

Do I need to create an account?

No. All PureBuild tools work without any sign-up or registration. Your data stays in your browser and is never sent to our servers.

What tools does PureBuild offer?

PureBuild offers 9+ specialized calculators including: Equity Calculator, Dilution Simulator, Runway Calculator, Unit Economics Modeler, Payment Gateway Fee Calculator, API Token Cost Estimator, Database Capacity Planner, Viral Coefficient Calculator, and True Hourly Rate Calculator.

Burn rate is the amount of money your startup spends each month. Gross burn is total expenses; net burn is expenses minus revenue.

How much runway should a startup have?

Most investors recommend 18-24 months of runway. Less than 6 months is considered critical and you should be actively fundraising or cutting costs.

How do I extend my runway?

You can extend runway by reducing expenses (cutting costs, renegotiating contracts), increasing revenue, or raising additional funding.

Burn rate is the amount of money your startup spends each month. Gross burn is total expenses; net burn is expenses minus revenue.

How much runway should a startup have?

Most investors recommend 18-24 months of runway. Less than 6 months is considered critical and you should be actively fundraising or cutting costs.

How do I extend my runway?

You can extend runway by reducing expenses (cutting costs, renegotiating contracts), increasing revenue, or raising additional funding.

Startup Runway Calculator: Burn Rate & Death Date Analysis

RUNWAY R-500

CASH BALANCEINPUT MODE

PROGRESS0/2 REQUIRED

Enter values and press =

50,000+ calculations

Last updated: 2025-01

Equity Calculator

Calculate option value and exit returns

Unit Economics

Calculate LTV:CAC and unit profitability

Dilution Simulator

Model equity dilution across rounds

Learn the Math

→ Runway Planning Guide → Essential Startup Metrics

Pro tip: All calculations run in your browser. Your data never leaves your machine. Use keyboard shortcuts for faster input.

Frequently Asked Questions

Runway is the number of months (or days) your startup can operate before running out of cash, calculated by dividing your cash balance by your monthly burn rate.

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