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.
How It Works
1
Enter the revenue a lender would underwrite
MRR, gross margin, monthly growth and churn, operating expenses, cash, and anything you already repay each month.
2
Set your own two constraints
How 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
See capacity, what limits it, and your runway either side
A conservative range, the binding constraint, the safe monthly payment, downside scenarios, and the runway before and after the capital — with an exportable repayment schedule.
Your recurring revenue
What a lender would be underwriting, and what it actually costs to run
Current MRR ($)
Gross Margin (%)
New + Expansion MRR (% / mo)
Monthly Revenue Churn (%)
Monthly Operating Expenses ($)
Cash in the Bank ($)
Existing Debt Service ($ / mo)
Your constraints and the deal
Both limits are yours to set — this calculator has no built-in credit policy
Capital as a Multiple of MRR (×)
Target Coverage / DSCR (×)
Amount You Are Considering ($)
Rate (% / yr)
Interest-Only (mo)
Amortization (mo)
Your Debt Capacity
The lower of what your revenue supports and what your cash flow services
Conservative capacity range
$164,994 – $247,491What limits the answer
Recurring revenue
4× underwritten MRR of $100,000$400,000
Cash flow
$12,000/mo of safe service at 1.25× coverage$247,491
$15,000/mo
$12,000
$126,973
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
$14,546/mo
1.03×
None
$49,104
Cash-flow positive
Cash-flow positive
The business covers its own costs before and after this capital. Debt here buys growth, not survival — which is the only position from which borrowing is genuinely optional.
Sanity-check the assumptions behind this with the Runway Calculator, the Churn Rate Calculator, and the SaaS Financial Model Template.
Base and downside
The same business under three things that routinely go wrong
Base
Exactly what you entered$247,491
Slower growth
Half the new + expansion MRR$247,491
Higher churn
1.5× your monthly churn$247,491
Lower margin
5 points off gross margin$164,994
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.
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 MRR
Underwritten 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 payment
Safe 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.
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.
Structure | Fits | Watch out for |
|---|---|---|
Revenue-based financing | Growth spend with a defined payback — hiring, paid acquisition | Payments scale with revenue, so a strong month costs more |
Revolving line of credit | Working-capital timing gaps — annual prepays, receivable lag | Easy to leave permanently drawn, which turns it into term debt |
Term loan | One-time, sized investments — an acquisition, a buyout | Fixed 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 SaaS Calculators
Debt capacity depends on retention, margin, and burn. These calculators pressure-test the inputs behind it:
Financial Health
Profit and Loss Statement Template — Build a P&L and export it to Excel, Google Sheets or PDF
SaaS Chart of Accounts Template — Generate a SaaS-specific chart of accounts and export it to Excel or Google Sheets
Burn Rate Calculator — Calculate net burn rate, cash runway, and burn multiple
ARR Calculator — Calculate annual recurring revenue from monthly subscriptions and annual contracts
MRR Calculator — Break down new, expansion, contraction, and churned MRR
Churn Rate Calculator — Measure customer and revenue churn with annualized projections
NRR Calculator — Track net revenue retention and gross revenue retention rates
SaaS Quick Ratio Calculator — Measure growth efficiency — MRR gained for every dollar lost to churn
Growth Rate Calculator — Calculate MoM, YoY, and CAGR growth rates from revenue data
Break-Even Calculator — Find the units and revenue needed to cover all costs and reach profitability
EBITDA Margin Calculator — Calculate EBITDA margin and benchmark against SaaS and industry norms
SaaS Runway Calculator — See how many months of cash you have left and model scenarios to extend it
SaaS Financial Model Template — Forecast MRR, ARR, burn, and runway over 24 months with scenario comparison and CSV export
SaaS ROI Calculator — Decide whether a hire, campaign, or tool returns more than it costs
SaaS Proration Calculator — Work out what a mid-cycle upgrade, downgrade, or cancellation costs
Customer Metrics
CAC Calculator — Measure customer acquisition cost and LTV:CAC ratio
LTV Calculator — Calculate customer lifetime value, lifespan, and LTV:CAC ratio
Payback Period Calculator — Calculate how long it takes to recover customer acquisition costs
Viral Coefficient Calculator — Measure your K-factor and model viral growth scenarios
SaaS Magic Number Calculator — Measure sales efficiency — net-new ARR per dollar of S&M spend
Pricing & Valuation
Markup Calculator — Calculate markup percentage, selling price, profit, and gross margin
Equity Dilution Calculator — Model how funding rounds affect founder ownership over time
SaaS Valuation Calculator — Estimate your company value using ARR multiples and growth-rate benchmarks
Revenue Multiple Calculator — See what ARR multiple your growth rate, NRR, and gross margin justify
Rule of 40 Calculator — Score your growth-plus-profitability against the Rule of 40 benchmark
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.
Offers 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.
Get 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.
Payments 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.
Every 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.
Connect your billing data and get a funding offer within 48 hours — for bootstrapped SaaS companies from $10K MRR.
Frequently Asked Questions
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