Free calculators for online business owners
VentriTools is a collection of free, browser-based calculators built for people who run online businesses — SaaS founders, indie developers, content site owners, and mobile app publishers. Every tool runs entirely in your browser with no sign-up, no account required, and no data sent to a server.
SaaS & business calculators
Tools for understanding the financial mechanics of a subscription or software business.
- MRR / ARR calculator — convert between monthly and annual recurring revenue, model growth scenarios
- Churn rate calculator — compute monthly and annual churn from lost customers or lost MRR
- LTV / CAC ratio calculator — see whether your customer acquisition cost is justified by lifetime value
- SaaS runway calculator — how many months of runway at current burn rate
- Gross margin calculator — revenue minus COGS, with margin % and a markup cross-reference
- Markup to margin converter — bidirectional: enter markup % to see margin %, or vice versa
Mobile app calculators
Tools calibrated to the economics of App Store and Google Play businesses.
- App Store revenue calculator — model net revenue after Apple's 30% or 15% commission tier, with an annual savings comparison between tiers
- Subscription app LTV calculator — price, churn, trial conversion, and platform cut → net LTV and break-even CPI
- CPI break-even calculator — D30 retention × net ARPU → revenue per install per month → maximum sustainable CPI at 3, 6, and 12-month payback targets
- UA ROAS calculator — D7 and D30 revenue per install, spend, installs → gross and net ROAS with a break-even line
- Retention curve projector — enter D1, D7, D30 retention to fit a power-law decay model and project D90 and D365
- DAU/MAU stickiness calculator — stickiness ratio with a quality label, days active per month, and optional engagement minutes
- App rating lift calculator — exactly how many 5-star reviews you need to reach a target rating, and how many in-app prompts to send
Content & media calculators
For bloggers, newsletter publishers, and content site owners monetising through ads and sponsorships.
- Ad revenue RPM calculator — bidirectional pageviews ↔ monthly revenue with RPM presets for AdSense, Ezoic, Mediavine, and AdThrive
- Sponsored content pricing calculator — niche-adjusted rate ranges based on pageviews and engagement quality
- Newsletter sponsorship CPM calculator — CPM ↔ rate per send, opens per send, monthly and annual sponsorship revenue
- Organic traffic value calculator — monthly sessions × CPC → equivalent paid traffic value, with CPC presets by niche
Security & developer utilities
Client-side tools for developers that handle sensitive input without touching a server.
- Hash generator — MD5, SHA-1, SHA-256, SHA-512 computed in-browser as you type. MD5 via a pure-JS RFC 1321 implementation; SHA variants via the Web Crypto API
- JWT decoder — paste a JSON Web Token to decode the header and payload, see time claims (iat, exp, nbf) as human-readable timestamps, and check whether the token is expired
- Base64 encoder / decoder — bidirectional, with standard and URL-safe (RFC 4648 §5) modes
Built for clarity
Every tool includes a plain-English explanation of the formula behind the result, so you understand what you're looking at rather than just copying a number. Each page also has an FAQ covering the underlying concepts — what churn rate actually measures, when to use SHA-256 vs MD5, why your rating needs hundreds of new reviews to move by 0.1 stars.
