Startup PMs operate under intense resource constraints with enormous strategic uncertainty. PM Toolkit gives you six calculators designed for the questions that matter most in the early stages: are we building the right thing, is the market big enough, and are our unit economics viable?
Startup PMs often have limited data while assessing the problem, the solution's fit with the market, unit economics, and runway. These calculations help make the assumptions in those decisions explicit.
PM Toolkit is free to use. Its calculators help document early estimates, but sparse data can leave results uncertain. Use the Market Sizing Calculator to build a bottom-up estimate and the experiment tools to check how much data a test needs.
Six calculators for early-stage product questions. Use the outputs as directional estimates when your data is limited.
Use the PMF Score Calculator to review the Sean Ellis 40% threshold alongside retention and engagement depth. These signals can help you decide whether to keep iterating or consider scaling.
Open CalculatorThe Market Sizing Calculator supports top-down estimates from market reports and bottom-up estimates from customers and revenue per customer. Compare the methods and document assumptions before using the figures in investor or planning discussions.
Open CalculatorThe ROI Calculator models returns and payback for product investments using your cost and benefit assumptions. Use it to explain resource choices to founders, investors, and colleagues, including uncertainty and non-financial considerations.
Open CalculatorCompare CAC by channel alongside the value and retention of the customers acquired. The CAC Calculator provides channel breakdowns; a lower cost alone does not establish that a channel is worth scaling.
Open CalculatorLTV helps put CAC in context, but early churn and incomplete cohorts can make it difficult to estimate. Choose a calculation method that fits the available data and make uncertainty explicit. In the LTV:CAC ratio, LTV is the numerator.
Open CalculatorThe A/B Test Suite covers pre-test planning, monitoring, and post-analysis. Define the hypothesis, sample, and decision rule before starting. A test may remain inconclusive if the data cannot distinguish the effects that matter.
Open CalculatorUse these calculators in sequence to answer the most critical questions at each stage of your startup journey.
Before increasing growth spending, review the Sean Ellis survey, retention, and engagement together. The 40% survey reference applies to very disappointed responses, not the combined PMF index. Use the results to identify questions for customer research.
Build a bottom-up TAM/SAM/SOM estimate from your customer data in the Market Sizing Calculator. Assess whether your target segment could support your business goals or whether you need to expand your ICP before scaling.
Use the ROI Calculator before committing resources to any major product or growth initiative. Model the expected return, payback period, and break-even point. This is especially valuable when presenting to founders or investors who need financial justification for resource allocation decisions.
Connect the CAC and LTV Calculators to compute your LTV:CAC ratio by acquisition channel. A ratio below 1:1 means estimated LTV is below CAC. Check the inputs, retention, and payback before deciding whether to change spending.
Use the A/B Test Planning Calculator to calculate required sample sizes before starting any experiment. After the test closes, analyse results in the Post-Analysis calculator to assess statistical evidence and practical value. Document every test outcome in a shared backlog so institutional learning accumulates over time.
Define a measurable hypothesis for each product change and a numeric success metric before each experiment starts. Use the experiment calculators to plan the test and assess its results as part of your build-measure-learn process.
Before scaling acquisition, review retention, customer value, and evidence of product-market fit. More spending can magnify losses if customer economics are weak. The PMF Score Calculator organizes several signals, but its score alone cannot establish readiness for growth investment.
Build the numbers for an investor deck using market sizing (TAM/SAM/SOM), PMF evidence, and unit economics projections. The calculators let you work through the assumptions behind those figures.
Use ROI and RICE Scoring to explain priorities to founders and investors. State the assumptions behind reach, impact, and effort so disagreements can focus on those estimates and their tradeoffs.
Review the Sean Ellis survey alongside retention and engagement signals. Use the PMF assessment to identify questions that need more customer or commercial evidence.
The Sean Ellis test asks users "How would you feel if you could no longer use this product?" A result of 40% or more answering "very disappointed" is a signal of product-market fit. The PMF Score Calculator combines this survey with retention, engagement depth, and qualitative indicators to help you assess the evidence together.
TAM is the total revenue opportunity for the defined market. SAM is the portion the product can serve given its focus, geography, and distribution. SOM is the share it can realistically capture over a stated period, given resources and competition. The calculator supports top-down and bottom-up estimates for these discussions.
Start recording acquisition costs and customer revenue when you have paying customers. With sparse data, treat LTV estimates as uncertain and test a range of retention assumptions. Compare the estimates with later cohorts before using them to justify larger acquisition budgets.
Plan experiment volume around the hypotheses, traffic, and resources available. Use the A/B Test Planning Calculator to estimate the sample needed for a chosen effect size. Low traffic may require a longer test or a different research method; sample size does not predict an exact completion date.