Startup finance basics
Most early-stage founders understand their product better than their cash flow. That gap shows up as surprise tax bills, underpriced contracts, and runway that disappears two months earlier than planned. This guide ties together the financial decisions you make in the first year — from estimating launch costs to issuing your first invoice — using SlashGit calculators you can run in a browser without a spreadsheet subscription.
Step 1: Estimate true startup and launch costs
Before fundraising or quitting your day job, build a realistic cost model. The Startup Cost estimator walks you through one-time expenses (incorporation, legal, initial inventory) and recurring burn (hosting, salaries, software subscriptions). Founders routinely underestimate SaaS seat counts and payment processing fees — add a 15% contingency line for items you will discover later.
Separate "must have to launch" from "nice to have after revenue." Your runway calculation should only include the must-haves. If the model shows fewer than six months of buffer at zero revenue, extend the timeline or reduce scope before you commit.
Step 2: Understand GST on revenue and expenses
For India-based startups, GST affects both what you charge and what you can claim as input credit. Use the GST Calculator to convert between inclusive and exclusive prices, and to split CGST/SGST versus IGST for interstate sales. Quoting a client "₹1,00,000" without clarifying whether GST is included creates invoice disputes that delay payment.
Model your effective tax position monthly: output GST on sales minus input credit on eligible expenses. If you are GST-registered, set aside collected tax in a separate account — it is not operating cash.
Step 3: Model loan and equipment EMIs
Bootstrapping often means a business loan, equipment lease, or founder personal loan rolled into the company. The EMI Calculator shows monthly outflow, total interest, and amortization schedule. Plug in the actual rate your bank offered, not the advertised teaser rate.
Add the EMI total to your monthly burn from Step 1. If debt service exceeds 20% of projected gross margin, negotiate tenure or delay the purchase until revenue covers it. Interest is a real cost that does not appear on a simple "expenses per month" list.
Step 4: Set prices using margin math
Revenue without margin is a hobby. The Profit Margin calculator converts between cost, selling price, markup, and margin percentage. Decide your target gross margin first — SaaS often aims for 70%+, services for 40–60% — then work backward to a minimum viable price.
Run the calculation for your cheapest and most expensive offering. If the low-tier product falls below 30% gross margin after payment fees and support time, bundle it differently or raise the floor price. Discounting without redoing this math is how startups grow revenue and still lose money.
Step 5: Plan personal runway with SIP projections
Founders who draw no salary for months still have personal expenses. The SIP Calculator helps model what disciplined monthly investing could yield over time — useful when deciding how much personal savings to allocate before the company can pay you. It does not replace an emergency fund; keep six months of personal expenses liquid before going full-time.
Step 6: Issue professional invoices early
Even pre-revenue pilots should practice clean billing. The Invoice Generator produces client-ready PDFs with line items, tax breakdown, and payment terms. Consistent invoicing speeds collections: include GSTIN, due date, and UPI or bank details on every document.
Review finances monthly with this loop: update startup costs, recalculate margins on any new pricing, check GST liability, and confirm EMI dates. The tools — Startup Cost, GST Calculator, EMI Calculator, Profit Margin, and Invoice Generator — give you numbers you can act on, not vague advice to "watch your burn."