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SaaS Debt Capacity Calculator

Debt capacity is not how much a lender will give you — it is how much your recurring revenue can safely repay once churn, gross margin, burn, and existing obligations are accounted for. Enter your numbers to see a conservative capacity range, which constraint is binding, and what the capital does to your runway.
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This calculator is powered by Founderpath — built to help founders access capital faster, deploy it smarter, and stay in control of their cash flow.

How it works

3 steps · Instant results
  1. 01
    Enter the revenue a lender would underwriteMRR, gross margin, monthly growth and churn, operating expenses, cash, and anything you already repay each month.
  2. 02
    Set your own two constraintsHow many months of MRR you would borrow against, and how much coverage you want to keep on every dollar of debt service. There is no hidden credit policy — both limits are yours.
  3. 03
    See capacity, what limits it, and your runway either sideA conservative range, the binding constraint, the safe monthly payment, downside scenarios, and the runway before and after the capital — with an exportable repayment schedule.
The calculator
Free · No email · Runs in your browser

Your recurring revenue

What a lender would be underwriting, and what it actually costs to run

Your constraints and the deal

Both limits are yours to set — this calculator has no built-in credit policy

Your Debt Capacity

The lower of what your revenue supports and what your cash flow services

Conservative capacity range
$164,994 – $247,491
Modest capacity
Low end is the worst of your three downside scenarios; high end is the base case. Capacity is 2.5× your current MRR.
What limits the answer
Recurring revenue4× underwritten MRR of $100,000
$400,000
Cash flow$12,000/mo of safe service at 1.25× coverage
$247,491

Cash flow is the binding constraint. Your revenue would support more, but the payments would not clear your coverage target.

Operating cash flow
$15,000/mo
Safe monthly debt service
$12,000
MRR at end of term
$126,973
Net MRR movement
1.00% / mo
Risk flags
  • The amount you entered is above the capacity this model supports. The gap is what you would be asking the business to absorb.

At $300,000

What the amount you entered does to payments, coverage, and runway

Amortizing payment
$14,546/mo
Coverage at that payment
1.03×
Interest-only payment
None
Total cost of capital
$49,104
Runway before
Cash-flow positive
Runway after
Cash-flow positive

Base and downside

The same business under three things that routinely go wrong

BaseExactly what you entered
$247,491
Slower growthHalf the new + expansion MRR
$247,491
Higher churn1.5× your monthly churn
$247,491
Lower margin5 points off gross margin
$164,994

Borrow against the number the downside cases still support. A capacity that only exists in the base case is a forecast, not a cushion.

This is an educational estimate built entirely from the numbers you entered — not financial advice, an underwriting decision, a credit approval, or a funding offer. Every calculation runs in your browser; nothing you type leaves your device. Lenders apply their own criteria, and a real offer may be higher or lower than anything shown here.

Know your capacity — now see what a real offer looks like

Connect your billing data and get an offer priced off your actual MRR and retention, so you can put a real rate and term back into the model.

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The guide

How to Model Debt Capacity for a SaaS Business

What Debt Capacity Means for Recurring Revenue

Debt capacity is the largest amount of debt a business can carry and still comfortably repay from the cash it generates. For a SaaS company the question is narrower than it sounds, because the asset being borrowed against is not inventory or equipment — it is a book of subscriptions that renews, expands, and churns. Two companies with identical ARR can have very different capacity: the one losing 4% of its MRR every month is borrowing against revenue that will have partly evaporated before the loan is repaid.

That is why this calculator asks for churn and gross margin rather than ARR alone. ARR tells you the size of the book today. Retention tells you how much of it will still be there at repayment, and margin tells you how much of it is actually cash rather than revenue.

The Two Constraints, Calculated Separately

Capacity is the lower of two independent limits. Showing them separately is the point: it tells you what would actually have to change for the number to move.

Revenue constraint = Multiple × Underwritten MRRUnderwritten MRR = the lower of today’s MRR and MRR projected to the end of the term at (new + expansion − churn)
Cash-flow constraint = present value of the safe monthly paymentSafe payment = (Operating cash flow ÷ target coverage) − existing debt service, where operating cash flow = (MRR × gross margin) − operating expenses

Worked example. A company at $100K MRR, 80% gross margin, $65K of monthly opex, growing 3% and churning 2% a month, with no existing debt and a target coverage of 1.25×. Gross profit is $80K, so operating cash flow is $15K a month. At 1.25× coverage the safe payment is $12K a month, which over a 24-month amortization at 15% supports roughly $248K. The revenue side, at 4× MRR, would allow $400K. Cash flow binds, so capacity is about $248K — and no amount of extra revenue multiple changes that. Cutting $10K of monthly opex, on the other hand, moves capacity by more than $130K.

Flip the same company to 4% monthly churn against 3% growth and the projection turns negative: MRR at the end of a two-year term is below today’s, so the revenue constraint is sized on the smaller number. That is the mechanism by which churn — not ARR — sets the ceiling.

Why Both Coefficients Are Yours to Set

Most debt-capacity tools hide a credit policy inside a formula: a fixed multiple, an undisclosed risk band, a coverage ratio you never see. This one does the opposite. The multiple of MRR and the target coverage ratio are both inputs, defaulted to widely used planning conventions — commonly 2× to 5× MRR for revenue-based facilities, and 1.25× coverage — and clearly labeled as assumptions rather than approvals.

That is a deliberate limitation. A capacity number stated with false precision is worse than no number, because it invites a founder to treat a spreadsheet output as an underwriting decision. Nothing here is a credit approval, a pre-qualification, or an offer; real lenders apply their own criteria and will reach a different number. What the model can do honestly is show you the shape of the constraint and how sensitive it is to the things you control.

When the Right Answer Is Zero

Capacity is not a target. There are situations where the model returns a positive number and borrowing is still the wrong decision, and the calculator flags them rather than burying them:

Gross profit does not cover operating expenses

There is no cash flow to service debt from, so any payment comes out of the loan itself. Borrowing here buys time, not capacity — and the repayment arrives before the problem is fixed. Cutting burn is the cheaper move; see the Burn Rate Calculator.

Churn exceeds new and expansion MRR

The book is shrinking, so repayment gets harder every month while the obligation stays fixed. Fix retention first — the Churn Rate Calculator and NRR Calculator size the leak.

One customer carries most of the revenue

Capacity sized against recurring revenue assumes the revenue is durable. A single renewal that could remove a third of it is the risk this model cannot see, and the one a lender will ask about first. Measure it with the Customer Concentration Calculator and re-run this page on the revenue that would remain.

The capital does not extend runway

If the new payment costs more each month than the capital buys, runway after the raise is shorter than before it. That is the signature of borrowing to cover a burn rather than to fund growth.

The use of funds has no return

Capacity says you could repay it. Whether you should depends on what the money does — test that separately with the SaaS ROI Calculator.

Which Structure Fits Which Use Case

Capacity is one number, but the right instrument depends on what the cash is for and how predictable the repayment is. None of these is universally better — they fail in different ways.

SaaS debt structures by use case
StructureFitsWatch out for
Revenue-based financingGrowth spend with a defined payback — hiring, paid acquisitionPayments scale with revenue, so a strong month costs more
Revolving line of creditWorking-capital timing gaps — annual prepays, receivable lagEasy to leave permanently drawn, which turns it into term debt
Term loanOne-time, sized investments — an acquisition, a buyoutFixed payment regardless of how the month went

Compare the structures in more depth on the SaaS financing hub and the SaaS debt financing guide, or read how Founderpath structures revenue-based financing, a line of credit, and term loans.

Capacity, Runway, and the Decision You Are Actually Making

The reason this calculation matters is that the alternative to debt is usually equity, and equity is priced against the same recurring revenue. A founder who can safely carry $250K of debt against a growing, well-retained book rarely needs to sell a permanent share of the company to fund a hire or a growth channel. Model what that share would cost with the Equity Dilution Calculator before deciding the two options are equivalent.

Founderpath provides non-dilutive capital to bootstrapped SaaS founders with at least $10K MRR — priced off connected billing data, repaid from revenue, with no dilution and no board seats. If you take an offer, put its real rate and term back into the calculator above: capital whose true cost changes the answer should change the decision. A wider set of operating benchmarks lives in the SaaS metrics hub.

Related calculators
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Related SaaS Calculators

Debt capacity depends on retention, margin, and burn. These calculators pressure-test the inputs behind it:

Financial Health

Beyond the calculator

Capacity is the ceiling. An offer is the actual number.

Founderpath prices capital off your recurring revenue — no dilution, no board seats.

This calculator sizes what your revenue and cash flow can safely carry using assumptions you chose. What it cannot tell you is what a lender will actually offer, at what rate, over what term. Connecting your billing data replaces every estimate above with real numbers — and if the answer is that you should borrow less, that is worth knowing before you sign.

Try Founderpath Free

Founderpath funds bootstrapped SaaS companies from $10K MRR of recurring revenue.

  • Sized against your real recurring revenueOffers are underwritten on connected billing data — MRR, retention, and growth as they actually are, not as a spreadsheet projects them. No pitch deck, no forecast to defend.
  • A stated total cost you can put back in the modelGet the all-in cost up front rather than a headline rate, so you can enter it in the rate field above and see whether the capacity still clears your coverage target.
  • Repay from revenue, not on a fixed schedulePayments flex with revenue, which is the single biggest difference between debt that fits a SaaS business and debt that does not. A slow month costs less rather than breaking the covenant.
  • Keep the equity your capacity was built onEvery dollar of recurring revenue you built is what creates this capacity. Borrowing against it costs a known amount and ends; selling equity to fund the same gap is permanent.
  • Close in 24–48 hoursConnect your billing data and get a funding offer within 48 hours — for bootstrapped SaaS companies from $10K MRR.
Questions
11 answers

Frequently asked questions

Debt capacity is the most debt a business can carry and still repay comfortably from the cash it generates. For SaaS it is set by two independent limits: how much recurring revenue a lender would size against, and how much monthly payment your operating cash flow can cover while keeping a coverage cushion. Your capacity is the lower of the two — and knowing which one binds tells you what would actually have to change to raise it.
Model them as one calculation, not two. Capacity tells you the largest amount you can service; runway tells you whether the resulting payment leaves you enough months to operate. This calculator shows runway before and after the capital, so you can see the case that catches founders out: the loan adds cash on day one but its monthly payment costs more than the cash buys, and runway ends up shorter than before. For the runway calculation on its own, use the SaaS Runway Calculator, and for the full forecast the SaaS Financial Model Template.
Revenue-based facilities commonly size somewhere between 2× and 5× MRR, but treat that as a planning convention rather than a rule — this calculator makes the multiple an input precisely so you can test it. The more important point is that the multiple is often not what limits you. If your operating cash flow cannot cover the resulting payment at your target coverage, the cash-flow constraint binds first and a higher multiple changes nothing.
Both, but they answer different questions. ARR sizes the opportunity; churn decides how much of it is still there at repayment. A $2M ARR business losing 4% of MRR monthly is a materially different credit from a $2M ARR business losing 1%, because the second one will still have most of its book when the last payment is due. This model reflects that by underwriting the lower of today’s MRR and MRR projected to the end of the term, so churn directly reduces capacity rather than sitting in a footnote.
Debt service coverage ratio is operating cash flow divided by total debt service. At 1.0× every spare dollar goes to the lender and any bad month is a missed payment; 1.25× keeps a 25% cushion, which is a common planning target. Below 1.0× the payment is larger than the cash generated to pay it — the calculator flags that outright. Set the target you actually want to live with; it is an input here, not a hidden policy.
Criteria vary by lender, and no calculator can tell you what one will approve. In practice most SaaS lenders look at the same things this model uses: a genuinely recurring revenue base, retention healthy enough that the book survives the term, gross margin high enough that revenue converts to cash, and operating cash flow that covers the payment. Documentation is usually connected billing and banking data rather than a pitch deck. Founderpath funds bootstrapped SaaS companies from $10K MRR of recurring software revenue — a company at $150K ARR is inside that range, though the offer still depends on retention and margin.
No — it moves cash around rather than creating it. An interest-only period lowers your payments early, which genuinely helps when the use of funds needs months to produce a return, but capacity here is sized on the amortizing payment, because that is the hardest month you will have to survive. Sizing against the interest-only payment is how a facility that looked affordable becomes unaffordable the month principal starts.
When gross profit does not cover operating expenses, when churn exceeds new and expansion MRR, when the capital shortens runway rather than extending it, or when the use of funds has no measurable return. In those cases the model may still show a positive number and the honest answer is still zero — debt does not fix a retention or cost problem, it puts a deadline on it. Test the return on the spend separately with the SaaS ROI Calculator.
No. This is an educational estimatebuilt entirely from the numbers you enter and the two constraints you choose — not financial advice, an underwriting decision, a credit approval, or a funding offer. It does not encode any lender’s credit model, including Founderpath’s. A real offer is priced off your connected billing data and may be higher or lower than anything shown here.
Equity is priced against the same recurring revenue that creates your debt capacity, but it is permanent: you sell a share of every future dollar to fund a present gap. When the model shows real capacity and the use of funds has a defined payback, non-dilutive capital is usually the cheaper way to fund it. Founderpath provides revenue-based financing to bootstrapped SaaS founders from $10K MRR — no dilution, no board seats. Model what a round would cost with the Equity Dilution Calculator.
Yes — 100% free, no signup or email required. Every calculation runs in your browser, nothing is stored, and none of your financial inputs leave your device. Export the full repayment and cash schedule to CSV as often as you like.