Startup Fund Calculator

Starting a business typically involves a period before the business generates enough income to replace your salary. That gap is covered from personal savings — separate from business capital. Many new businesses fail before reaching profitability when this runway is underfunded.

Personal runway covers monthly living costs during the pre-income period, a buffer for the runway exceeding plan (businesses often take longer to profit than founders initially project), and non-negotiable personal costs like insurance, minimum debt payments, family obligations.

Separately from personal runway, the business requires startup capital: equipment, legal setup, inventory, marketing, initial team, software. This calculator focuses on the personal side — what to save as an individual before quitting your job. Business capital is a separate plan.

Common ranges: 12-18 months personal runway for a service business (consulting, coaching, freelance work). 18-24 months for a product business. 24-36 months for a tech startup that requires development before revenue. Under-planning creates risk; over-planning reduces it.

How to use it

Input personal monthly living cost, expected months of runway needed, any upfront startup costs you're self-funding, and current savings toward the business. The tool calculates target fund and gap.

What the result means

Target fund is the amount to have saved before quitting. Gap is what remains to save from now. Months to target (at current pace) shows when quitting becomes financially feasible — often longer than founders anticipate, but realistic planning reduces risk of early failure from depleted reserves.

Planning tool, not financial advice.

A worked example

Try the defaults: monthly living cost of 3,000, runway months needed of 18, self-funded startup costs of 10,000, current savings of 15,000. The tool returns 64,000.00. You can adjust any input and the result updates as you type — no submit button, no reload. That's the real power here: seeing how sensitive the output is to one or two assumptions.

What moves the number most

The result responds to Monthly Living Cost, Runway Months Needed, Self-Funded Startup Costs, and Current Savings. Not every input has equal weight. Adjusting one input at a time toward extreme values shows which ones move the result most.

The formula behind this

Target sums personal living costs (monthly × runway months) and upfront startup costs. Gap is target minus current savings. Everything the calculator does is shown in the formula box below, so you can check the math against your own spreadsheet if you want.

Using this to think, not predict

Financial plans diverge from reality by month six — new information arrives and reshapes the picture. The point of running projections isn't to predict accurately ten years out; it's to reduce uncertainty in the decision you're making this week.

What this doesn't capture

Real plans are revisited against new information every year or two. The result here is a reasonable direction, not a destination. It is a starting point for thinking, not a commitment to a specific future.