Free tools for founders
Finance and SaaS tools built on a real accounting engine. No signup, no email wall — just answers in under a minute.
Founder Toolkit
Metrics and calculators every SaaS founder needs.
SaaS Runway Calculator
See how many months of cash you have left from your balance and monthly burn.
OpenRule of 40 Calculator
Check if your growth rate plus profit margin clears the famous 40% bar.
OpenMRR / ARR Calculator
Turn your plans and subscribers into monthly and annual recurring revenue.
OpenLTV : CAC Calculator
Measure customer lifetime value against acquisition cost.
OpenCap Table & Dilution Calculator
Model ownership and dilution across funding rounds.
OpenBurn Rate & Burn Multiple Calculator
Work out your monthly cash burn and your burn multiple against new ARR.
OpenChurn & Retention (NRR / GRR) Calculator
Calculate net and gross revenue retention from your MRR movements.
OpenBreak-even Point Calculator
Find the units and revenue you need to cover your fixed costs.
OpenSaaS Valuation Estimator
Estimate your SaaS valuation from ARR and growth using revenue multiples.
OpenSAFE / Convertible Note Calculator
See what ownership a SAFE converts to using the cap and discount.
OpenROI / Ad-Spend Calculator
Calculate ROI, ROAS, CAC and payback from spend and revenue.
OpenBusiness Tools
Invoicing, revenue and tax helpers for any business.
Stripe CSV → Clean P&L
Upload a Stripe export and get gross revenue, fees, refunds and net — categorised.
OpenStripe Fee Calculator
See what you keep after Stripe fees — or what to charge to net a target.
OpenCSV Statement Analyzer
Upload any Payoneer or bank CSV to auto-categorise transactions and see where your money goes.
OpenPayment Gateway Comparison
Compare fees, payout times and tax handling across Stripe, PayPal, Paddle, Lemon Squeezy and more.
OpenDiscount / Coupon Impact Calculator
See how a discount hits your margin and the extra volume needed to break even.
OpenSubscription Proration Calculator
Work out the prorated charge when a customer changes plan mid-cycle.
OpenFree Invoice Generator
Create a professional invoice and download a PDF in under a minute.
OpenFree Quote / Estimate Generator
Create a professional quote or estimate and download a PDF.
OpenFree Receipt Generator
Create a payment receipt and download a PDF.
OpenFree Purchase Order Generator
Create a purchase order for a vendor and download a PDF.
OpenFree Credit Note Generator
Create a credit note against an invoice and download a PDF.
OpenFree Expense Report Builder
Build an expense report with categories and totals, download a PDF.
OpenSaaS Sales Tax / VAT Checker
Find out where selling your SaaS creates a tax obligation.
OpenPersonal Finance
Tools for your own money, not just the business.
Self-Employment Tax Calculator
Estimate the tax you owe on freelance and founder income.
OpenQuarterly Estimated Tax Calculator
Estimate your quarterly estimated-tax payments (SE + income tax).
Open1099 Contractor Tax Estimator
See how much of your 1099 income to set aside for taxes.
OpenHome-Office Deduction Calculator
Compare the simplified and regular home-office deduction methods.
OpenUtilities
Fast, free developer and maker utilities.
OG Image Generator
Generate social share images for your links in seconds.
OpenEmail Signature Generator
Build a professional email signature from templates and copy it into your mail app.
OpenBusiness Card Builder
Design a business card from templates — including a Nothing-style dot-matrix — and print it.
OpenJSON Formatter
Pretty-print, validate and inspect JSON instantly in your browser.
OpenCron Expression Builder
Build and read cron schedules in plain English.
OpenUUID Generator
Generate v4 UUIDs in bulk, with formatting options.
OpenBase64 / URL Encoder & Decoder
Encode and decode Base64 and URL strings instantly.
OpenJWT Decoder
Decode a JWT to read its header and payload (not verified).
OpenRegex Tester
Test a regular expression against text with flags and capture groups.
OpenHash Generator
Generate SHA-1, SHA-256, SHA-384 and SHA-512 hashes from text.
OpenUnix Timestamp Converter
Convert between Unix epoch timestamps and human-readable dates.
OpenSlug Generator
Turn any text into a clean, URL-friendly slug.
OpenCase Converter
Convert text between camelCase, snake_case, kebab-case, Title Case and more.
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