PlotGTM is a free go-to-market budget calculator that helps users create a costed marketing plan. It sizes a marketing budget, allocates spending across the PESO channel mix (Paid, Earned, Shared, Owned), models the sales funnel from leads to revenue, and projects financial metrics such as ROI, ROMI, CAC, LTV, and capital needs. The tool is designed for B2B marketers, founders, and growth teams who need to structure their go-to-market strategy around specific financial inputs and targets. The calculator provides three interchangeable strategies. Goal-driven mode works backwards from a specific revenue target to determine the necessary budget and lead volume. Unit economics caps the marketing spend at one third of the campaign's projected gross profit. Percentage of revenue anchors the budget to a percentage of current annual revenue. An Auto mode selects the most suitable strategy based on the user's inputs. Users define growth levers including lead volume, conversion rates, average order value, and purchase frequency. The model applies these inputs directly without hidden multipliers and provides an achievability indicator that assesses whether the selected channel mix can support the targets. The tool calculates the gap between a user's existing run rate and their goal, focusing on the incremental revenue required. Typical workflows involve inputting current business metrics, selecting a strategy, adjusting the PESO mix, and reviewing the resulting budget, funnel projections, and return on investment. Users can save and compare multiple plans. PlotGTM supports connection to external AI agents through the Model Context Protocol (MCP). Its methodology incorporates benchmarks from sources like the Gartner CMO Spend Survey and industry standards for ROMI and conversion rates.