Best Free Runway & Burn-Rate Calculators 2026

Search for a "free runway calculator" and you land on two different kinds of product. One is a what-if calculator: type assumptions, get the runway or burn number, no account. The other is an FP&A platform: connect your accounting and billing systems, forecast from live actuals. Both are useful, for opposite jobs. This roundup picks the best free what-if calculators for the three questions a founder asks most about cash — how long until I quit my job, how efficient is my burn, and how many months of runway do I have — shows each running live, and draws the honest line between them and the paid platforms.

1. Calculator vs FP&A platform: two jobs

The most common mistake when shopping for a "free runway tool" is comparing a calculator to an FP&A platform as if they competed. They do not:

• A what-if calculator takes assumptions you type — savings, expenses, MRR, growth, burn — and returns the implied runway or burn metric instantly. No account, no accounting connection. It answers "what would happen if..." and works before you have any books.
• An FP&A platform connects to your accounting, payroll, and billing systems and forecasts from live actuals across the whole company. It answers "what does our connected data project" and requires real books to be useful.

The three tools featured below are calculators, chosen because the converting search intent — "free runway calculator" — is overwhelmingly people who want to model a number now, not connect their accounting. Each example is rendered live from the shipped engine at build time, so the inputs and outputs you see are real engine output, never hand-typed.

2. Free bootstrapped-runway calculator

The Bootstrapped Runway Calculator models the quit-your-job decision. It takes personal savings, monthly personal expenses, side income, current MRR, monthly MRR growth, and monthly business costs, and returns personal runway in months, the month you become ramen-profitable, the month you become fully profitable, the break-even MRR, and a month-by-month timeline. A worked run:

The engine returns the full path-to-full-time picture from those six typed numbers, including the months to ramen-profitable and fully-profitable and whether they land inside the personal runway window. Because it needs no accounting connection, you can test different growth rates before committing to the quit. The calculator shows the MRR you need before you can drop the day-job income.

3. Free burn-multiple calculator

The Burn Multiple Calculator answers the capital-efficiency question: how much net cash are you burning for each dollar of new ARR? It takes monthly net burn and monthly net new ARR, and returns the burn multiple, a verdict band, and the annualized figures. A worked run:

The engine returns the burn multiple and a verdict from the two typed inputs: under 1 is exceptional, 1 to 1.5 great, 1.5 to 2 good, 2 to 3 concerning, above 3 unsustainable. It is the fastest way to sanity-check whether your spend is producing proportionate growth, with no signup. How it relates to runway is in burn multiple vs runway for founder decisions.

4. Two more free burn tools

Two further free calculators round out the cash picture, both no-signup and computed from typed inputs:

• Monthly Burn Rate Calculator — itemize your monthly costs and cash on hand, and it returns total monthly burn and months of runway remaining.
• Startup Runway Calculator — the classic cash-divided-by-burn runway view, for a venture-funded or pre-revenue runway estimate. The method is in how to plan startup runway.

Between the four, you can model the quit decision (bootstrapped runway), capital efficiency (burn multiple), and remaining cash (monthly burn rate and startup runway) without signing up for anything or connecting your books.

5. Honest comparison to the paid platforms

The named alternatives most founders find searching for runway tooling are FP&A platforms, not calculators. Positioning checked on October 18, 2026:

Tool	Type	Pricing	Needs accounting connection?
BILL Cash Flow Forecasting[1][2]	Forecasting in AP/AR suite	Included on Team ($65/user/mo) and above, QuickBooks Online users	Yes
Lucanet (formerly Causal)[3]	Extended planning and analysis platform	Sales-led	Yes (for actuals)
This hub's free calculators	What-if calculators	Free, no signup	No

Read this honestly: if you already have books and want a connected, multi-driver forecast that updates from your real accounting, an FP&A platform is the right tool, and BILL Cash Flow Forecasting and Lucanet's planning platform each do that job. None of those is what the free calculators replace. The calculators win when you want to model a scenario — a quit-your-job runway, a burn-multiple check, a monthly burn estimate — without connecting an accounting system you may not even have set up. They are complements, not substitutes: model with a calculator, forecast with a platform. (Note: the standalone Finmark product shut down April 1, 2026, with its technology absorbed into BILL Cash Flow Forecasting^[3].)

One thing the calculators do that a platform cannot easily: run on a founder's personal numbers that never touch the company books. A platform forecasts company financials; only a what-if calculator answers "how many months until my MRR covers my rent."

6. Which free tool for which question

• "When can I quit my job?" → Bootstrapped Runway Calculator (savings, MRR growth, ramen vs fully profitable).
• "Is my burn efficient?" → Burn Multiple Calculator (net burn ÷ net new ARR, with verdict bands).
• "How many months of cash do I have?" → Monthly Burn Rate Calculator or Startup Runway Calculator.
• "I need a connected forecast from my real books." → an FP&A platform (BILL Cash Flow Forecasting, Lucanet) — connect your accounting.

Re-verify the platforms' pricing before committing; FP&A pricing is mostly quote-driven and changes with company size. For the calculators, nothing to re-verify: they are free, need no signup, and compute from numbers you type.

Alternative-tool positioning checked against official sources on 2026-10-18.

Frequently asked questions

What is the best free runway calculator in 2026?

For modeling a founder's path to full-time, the free Bootstrapped Runway Calculator on aibizhub is the most directly useful: it takes personal savings, monthly personal expenses, side income, current MRR, monthly MRR growth, and monthly business costs, and returns personal runway in months, months to ramen-profitable, months to fully-profitable, the break-even MRR, and a month-by-month timeline. It runs entirely on numbers you type with no signup and no accounting connection, so it works before you have any revenue. The paid FP&A tools (BILL Cash Flow Forecasting, or Lucanet, which absorbed Causal) solve a different job: they connect to your accounting and billing systems to forecast from live actuals. Use the calculator to model a scenario; use a platform to forecast from connected data.

What is a good burn multiple, and how do I calculate it free?

Burn multiple is net cash burned divided by net new ARR added, and lower is better: under 1 is exceptional, 1 to 1.5 is great, 1.5 to 2 is good, 2 to 3 is concerning, and above 3 is unsustainable. The free Burn Multiple Calculator computes it from two inputs — monthly net burn and monthly net new ARR — and returns the multiple, a verdict band, and the annualized burn and net new ARR. It needs no signup and no accounting connection, so you can sanity-check the metric in seconds from numbers you already track. A burn multiple of 2 means you are spending two dollars of net cash for every dollar of new annual recurring revenue, which is the line between good and concerning.

Are these free calculators the same as an FP&A platform?

No, and that is the point. FP&A tools such as BILL Cash Flow Forecasting (included on BILL's Team plan, $65 per user per month, and above, for QuickBooks Online users) and Lucanet's planning platform (which absorbed Causal) connect to your accounting, payroll, and billing systems and forecast from live actuals across the whole company. The free calculators are what-if tools: you type assumptions and get the runway, burn-multiple, or burn-rate output instantly, with no connection and no signup. Use a calculator to model a single scenario — a quit-your-job runway, a burn-multiple check, a monthly burn estimate. Use a platform when you need a connected, multi-driver forecast that updates from your real books.

Which free tool should a bootstrapped founder use to decide when to quit their job?

Use the free Bootstrapped Runway Calculator, because it models the quit-your-job decision directly. You enter personal savings, monthly personal expenses, any side income, current MRR, expected monthly MRR growth, and monthly business costs, and it returns how many months of personal runway your savings buy, the month your MRR covers your personal expenses (ramen-profitable), the month it covers personal plus business costs (fully profitable), and whether those milestones fall inside your runway window. Because it runs on typed assumptions with no accounting connection, it works pre-revenue and lets you test growth rates before committing. The paid FP&A platforms cannot help with this personal-runway decision; they forecast company financials from connected actuals, not a founder's savings-versus-MRR timeline.