Free B2B Marketing Calculators (2026): Our Growth Math Extension

We built free B2B marketing calculators as a browser extension because our team kept rebuilding the same five spreadsheets across client engagements at Global One Digital. Growth Math packages them into a one-click popup that works offline, supports English and Russian, and asks for nothing in return — no email gate, no telemetry, no upsell pop-ups.

What is in Growth Math

Five calculators, all working entirely client-side: SEO ROI projection, automation savings, CAC and LTV health check, A/B test sample size, and SaaS pricing to ARR forecast. Every input stays in your browser. Press one button to calculate, press another to copy a shareable summary for your team Slack or a board deck.

Why a browser extension instead of a web app

Three reasons. First, a popup launches faster than a tab — useful when you are deep in HubSpot or Notion and need a quick check. Second, no server means no privacy concerns about typing real revenue numbers into a third-party tool. Third, the install creates a persistent reminder that the tool exists; web bookmarks get forgotten, toolbar icons do not.

Calculator 1 — SEO ROI projection

You enter the number of commercial keywords you target, average search volume per keyword, target SERP position, conversion rates from visitor to lead and lead to deal, average deal size, and monthly SEO investment. The calculator uses Advanced Web Ranking 2024 click-through-rate data per position with a realistic 12-month ramp curve (5% of steady state in month 1 rising to 100% by month 12) — most agency-built calculators skip the ramp and over-promise month-1 results. Output: monthly visits, leads, deals, revenue, break-even month, and 12-month ROI percentage. Particularly useful before signing a retainer for B2B SaaS SEO services.

Calculator 2 — Automation savings

You enter task volume per week, minutes per task, hourly rate of the person currently doing it, manual error rate and cost per error, and one-time build cost for the automation. Output: hours freed monthly, labor and error-cost savings, payback period, and three-year net savings. The math conservatively models 95% labor automation and 92% error reduction — full elimination is rare in real automation engagements like business process automation or n8n consulting.

Calculator 3 — CAC and LTV health

You enter monthly marketing and sales spend, new customers per month, average MRR per customer, gross margin, and monthly churn rate. Output: CAC, LTV, LTV:CAC ratio, CAC payback in months, and a letter grade A/B/C/D based on standard SaaS health benchmarks (ratio above 5 is A, 3-5 is B, 1.5-3 is C, below 1.5 is D). The grade colour-codes in the popup so a CFO can spot trouble at a glance.

Calculator 4 — A/B test sample size

You enter baseline conversion rate, minimum detectable effect, confidence level (90, 95, or 99 percent), statistical power (80, 85, or 90 percent), and daily visitors per variant. Output: sample size per variant, total sample, and days plus weeks to reach significance at your current traffic. The math uses the standard two-proportion z-test formula — same one Optimizely, VWO, and Convert use under the hood. Useful before kicking off a test to confirm whether your traffic can detect the effect size you care about.

Calculator 5 — SaaS pricing to ARR forecast

You enter Starter / Growth / Enterprise tier prices, your expected mix of new customers per tier, and monthly churn. Output: ARPU, MRR after 12 months, ARR after 12 months, and ARR after 36 months. The model uses month-by-month MRR simulation with exponential retention rather than the lazy «annual revenue × growth multiplier» approximation that misleads founders about ARR timing. Particularly useful when comparing pricing models or building a board update.

Two languages, no sign-up

The extension ships with English and Russian locales out of the box. Browser language auto-detects on first install, or you can switch manually in the popup or options page. No sign-up, no analytics, no telemetry — the source is 200 lines of JavaScript that you can inspect in chrome://extensions with developer mode on. We do not transmit anything to development-web.com or any third party; the only network reference is an attribution link in the footer.

Where we use these calculators in client work

The SEO ROI calculator runs during every discovery sprint for SEO engagements with US-based SaaS — it sets realistic expectations about timeline-to-payback so we are not selling against fantasy. The automation savings calculator runs in every automation pilot: build cost goes on one side of the math, three-year net savings goes on the other, and we will not start a build that does not pay back within 12 months. CAC/LTV runs quarterly with growth-stage clients to spot when paid-acquisition costs are creeping past sustainable levels.

Download links

The extension is on three browser stores and free everywhere:

• Chrome Web Store — works in Chrome, Brave, Arc, Vivaldi, and any Chromium-based browser
• Firefox Add-ons — works in Firefox and Tor Browser
• Microsoft Edge Add-ons — official Edge channel

Things the calculators do not do

Three things by design. They do not save your inputs anywhere — close the popup, the numbers are gone (this is a feature, not a bug). They do not call APIs for live keyword volume or search-console data — those are paid integrations we run for clients but cannot bundle in a free extension. They do not predict the unpredictable — SEO ROI assumes a typical SaaS ramp curve, real results depend on competition, content quality, and link velocity that no calculator can model from input numbers alone.

Roadmap and feedback

Next versions will add: a sales velocity calculator (deal size × number of opportunities × win rate / sales cycle), a content production budget planner, and possibly a Wordstat-style keyword volume estimator using public data. If you have a calculator you keep rebuilding in spreadsheets that fits the same B2B SaaS toolkit theme, drop us a note via the contact form — that is exactly how this extension started.

About Global One Digital

Global One Digital is a B2B SEO and automation agency for Series A through Series C SaaS companies in the US and EU. We built Growth Math because we kept rebuilding the same five calculators in spreadsheets for client engagements — packaging them into a free browser extension made the work re-usable and gave our clients something they could use independently. Learn more about our team or book a discovery call.