Smart Business Math

Runway Calculator

Translate cash balance and net burn into months (and days) remaining.

Calculator

From the Burn Rate Calculator: expenses − revenue.

Results

Runway

8 mo

About 244 days at current burn

Approx. days remaining

244

What this means

Roughly 6–12 months of runway is a workable planning window—still watch burn if revenue slips.

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Runway Summary

Runway (months) = Cash ÷ Monthly net burn. If burn is zero or negative, runway is open-ended at current performance.

Explanation

Runway is how long cash lasts at the burn rate you entered.

Business implication: decisions about hiring, ads, and pricing should always be checked against remaining runway.

Step-by-step example

Cash $120,000, net burn $15,000/mo:

  1. Runway: $120,000 ÷ $15,000 = 8 months

Formula

Runway months = Cash balance ÷ Monthly net burn

(If net burn ≤ 0, runway is treated as open-ended.)

Helpful tips

  • Plan defaults/fundraising when runway drops under 6–9 months—not at zero.
  • Recalculate after every major hire or campaign.

FAQ

What is runway?

Runway is how long your current cash lasts at today’s net burn rate—usually expressed in months.

What if net burn is zero or negative?

Runway is effectively open-ended at that spend level (you are not drawing down cash from operations). You can still run out of cash if revenue drops or large one-time costs hit.

Should I include committed funding?

Only count cash you actually control. Verbal commitments and unpaid invoices are not runway until collected.

How accurate is this calculator?

It assumes constant burn. Hiring, marketing spikes, or revenue swings change runway—recompute often.

Related tools

Key terms

Runway

Definition. How many months current cash can fund the business at the current burn rate.

In simple terms. Runway is a planning clock—not a prediction of success. It tells you how long you have to grow revenue, cut costs, or raise funds before cash hits zero.

Runway (months) ≈ cash balance ÷ monthly burn rate

Example. $60,000 cash and $10,000/month burn → about 6 months of runway.

Common mistake. Using an optimistic burn that ignores upcoming known costs, or forgetting taxes and owner draws.

Related calculators. Runway Calculator, Burn Rate Calculator

Related terms. Burn rate, Cash flow

Burn rate

Definition. How fast a business spends cash—usually net monthly cash decrease when expenses exceed cash in.

In simple terms. Startups and early freelancers use burn to understand how aggressive spending is relative to cash on hand. Positive cash generation is the opposite of burn.

Burn rate ≈ monthly cash out − monthly cash in (when out > in)

Example. Spend $12,000 and collect $7,000 in a month → about $5,000 monthly burn.

Common mistake. Calling all expenses “burn” even when revenue covers them, or ignoring one-time cash events.

Related calculators. Burn Rate Calculator, Runway Calculator

Related terms. Runway, Cash flow

Cash flow

Definition. The movement of cash in and out of the business over a period—not the same as profit on paper.

In simple terms. You can be profitable and still short on cash if customers pay late or you buy inventory up front. Cash-flow views focus on timing.

Net cash flow = cash in − cash out (for the period)

Example. Invoicing $20,000 but collecting $8,000 while paying $12,000 in bills creates a cash squeeze despite strong sales.

Common mistake. Equating booked revenue with cash in the bank.

Related calculators. Cash Flow Forecast Calculator, Accounts Receivable Days Calculator

Related terms. Accounts receivable days, Burn rate, Runway

See all terms in the Glossary →

Notes & Assumptions

Cash runway is a standard operating metric for startups and cash-tight small businesses.

Last reviewed: July 2026