# alexzaremsky.com
> Engineering-Led Growth, SEO & Marketing Lab. 100% Free Calculators & Primary Data Studies.

## Core Calculators & Tools
- [ROAS & Break-Even Performance Engine](https://alexzaremsky.com/tools/roas-calculator/): Target ROAS, break-even thresholds, agency fees, and margin-adjusted profit.
- [SaaS Reverse Funnel: Limiting CAC, CPL & Max CPC](https://alexzaremsky.com/tools/saas-limiting-cac-cpc/): Work backward from LTV to calculate maximum allowable CAC, CPL, and click bids.
- [Complete Cohort & Unit Economics Simulator](https://alexzaremsky.com/tools/unit-economics-calculator/): Model customer acquisition cohorts down to net operating profit.
- [PPC Scaling & Sensitivity Matrix Forecaster](https://alexzaremsky.com/tools/ppc-sensitivity-matrix/): 25-scenario 2D matrix modeling Net Profit and ROAS across CPC and CR fluctuations.
- [Margin vs Markup Calculator](https://alexzaremsky.com/tools/margin-markup-calculator/): Instant conversion between gross profit margin and markup on cost.
- [E-Commerce P&L & Operating Profit Estimator](https://alexzaremsky.com/tools/pnl-profit-calculator/): Itemize COGS, warehousing, software, and ad spend for EBITDA forecasting.
- [SaaS LTV, CAC & Payback Period Calculator](https://alexzaremsky.com/tools/ltv-cac-calculator/): Evaluate churn-adjusted LTV, 3:1 ratio health, and CAC recovery speed.
- [CPC, CPM & CPA Cross-Metric Model](https://alexzaremsky.com/tools/cpc-cpm-cpa-calculator/): Multi-variable conversion calculator for paid advertising campaigns.
- [PPC Search Budget & Max Bid Forecaster](https://alexzaremsky.com/tools/ppc-budget-forecaster/): Forecast Google Search ad budgets and compute margin-based break-even bids.
- [Backlink Quantity & SERP Gap Estimator](https://alexzaremsky.com/tools/backlink-calculator/): Estimate referring domains needed to reach Google Top 10 based on KD and DR.
- [A/B Testing Statistical Significance Engine](https://alexzaremsky.com/tools/ab-test-calculator/): Two-tailed Z-test, p-value calculation, confidence intervals, and Evan Miller sample sizes.
- [Email Marketing ROI & List Decay Estimator](https://alexzaremsky.com/tools/email-roi-calculator/): Broadcast campaign revenue, revenue per subscriber, ESP ROI, and 12-month decay.

## Author & Methodology
- Author: Alex Zaremsky (Growth Engineer & Search Strategist)
- Methodology: 100% Free Tools, zero paywalls, client-side execution.