Business Finance Hub · Bedrocka Tools
Source-cited calculators for business owners,
operators, and founders.
The math behind every decision that moves real money — loans, runway, valuations, real-estate underwriting, pricing, taxes. Most calculators online are thin lead-capture forms wrapped around math nobody verifies. This site is the opposite: every formula is open-source, every rate cites the primary source, and every tool is reviewed quarterly by a named operator.
Calculators
Pick the math you actually need.
Lending
Business Loan Calculator
Payments, interest, amortization. Fixed rate or variable, any term.
Open calculator →SBA 7(a) Loan Calculator
Full SBA 7(a) cost including all four fees, up to $5M loan size.
Open calculator →Equipment Financing Calculator
Loan vs lease vs operating-lease, with §179 + bonus depreciation.
Open calculator →Invoice Factoring Calculator
True effective APR vs the 'just 2.5% per month' sales pitch.
Open calculator →
Operating Finance
Cash Runway Calculator
Default alive or default dead — with burn multiple.
Open calculator →CAC + LTV + Payback Calculator
The four numbers every SaaS / e-commerce operator runs — CAC, LTV, ratio, payback. Plus NRR-adjusted LTV and the magic number.
Open calculator →Cap Table + Dilution Calculator
Founder dilution math through a SAFE + priced round, with the standard YC post-money SAFE convention.
Open calculator →Business Valuation Calculator
Three methods side by side — DCF, revenue multiple, EBITDA multiple. The spread is the insight.
Open calculator →Break-Even Calculator
Units, revenue, contribution margin, margin of safety.
Open calculator →Working Capital Calculator
NWC, DSO, DIO, DPO, and the Cash Conversion Cycle.
Open calculator →
Real Estate
Pricing & Margins
Tax & Depreciation
Quarterly Estimated Tax Calculator
Quarterly federal tax payments for 1099 freelancers, contractors, and self-employed business owners — with IRS safe-harbor calc.
Open calculator →Payroll Tax Calculator (First Hire)
Fully-loaded employer cost for your first W-2 hire — FICA, FUTA, SUTA, workers' comp, benefits.
Open calculator →R&D Tax Credit Calculator (Section 41)
IRC §41 R&D credit — startup payroll tax election up to $500K, plus the standard income tax credit.
Open calculator →Self-Employment Tax Calculator
Schedule SE calculator — 15.3% SE tax with the SS wage cap, Medicare uncapped portion, and half-deductible-above-line.
Open calculator →
Learn
Concepts behind the math.
SBA & Government Programs
How SBA 7(a) Fee Schedules Actually Work
The 'fee' on an SBA 7(a) loan is actually four fees stacked. Most online calculators only count one. Here's the full breakdown — guarantee fee, ongoing fee, packaging, and prepayment — with the SBA SOP page numbers.
Startup Finance
What Is a Burn Multiple, and Why Bessemer's Threshold Matters
Burn multiple turned 'how much are you burning?' into 'how much are you burning per dollar of new revenue?' — a much more useful question. Here's the math, the tier thresholds, and where it stops applying.
Real Estate Investing
DSCR Loans for Residential Investors — What's Different from CRE
A DSCR loan on a 4-unit rental works differently from a $5M apartment-complex loan even though the formula is identical. The differences live in the thresholds, the lenders, and what the property has to prove.
Tax & Depreciation
Section 179 vs Bonus Depreciation — The 2026 Phase-Down Explained
Section 179 and bonus depreciation are two different rules that look similar. They stack in a specific order, the 2026 phase-down changes the math, and most online calculators get this wrong. Here's how to think about it.
Pricing & Margins
Why Margin and Markup Are Not the Same Number
When a vendor says '50% markup,' they mean 33.3% margin. When they say '50% margin,' they mean 100% markup. The relationship is not symmetric, and most operators have it backwards.
Operating Finance
Negative Cash Conversion Cycle — Amazon's Structural Advantage
If you collect from customers before you pay suppliers, you have negative working capital — and your business is literally being financed by everyone else's float. Amazon does it. Costco does it. Apple does it. Here's how.
What makes this different
Three things every Bedrocka Tools site does that the incumbents don't.
Open-source math
Every calculator's formula is published as TypeScript with Vitest tests in a public repo. Click "View source" in any math accordion to see the actual implementation. Bankrate, NerdWallet, and SmartAsset hide their math. We publish it.
Browse the math →Primary-source citations only
Every rate, fee, and threshold links to the original document — SBA SOPs, IRS publications, Federal Register notices, FASB codification. No "according to industry sources" hedging. The citation is the proof.
Read the methodology →Named operator, real bio
Reviewed and signed by Byron Malone— a decade of forming entities, running SBA conversations, negotiating term sheets, and modeling runway through more than one cycle. Not a content mill.
Read Byron's bio →About this site
Every formula ships as open-source TypeScript with Vitest tests. Every number links to a primary source. Every page is signed and reviewed quarterly by a named operator — not a content mill.
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