Free, interactive tools
Small, sharp tools that answer a real question. Start with the ones for learning, skill, and talent, then AI, startups, engineering, and a few big questions about time and the cosmos. No signup, runs in your browser.
Human knowledge & talent
How Long to Get Good?
Turn your weekly practice into real calendar time to reach each level of a skill, from not-terrible to mastery.
Skill Half-Life
How fast a skill fades when you stop using it, and how little review keeps it sharp.
The Forgetting Curve
Watch memory fade, and how each spaced review flattens the curve so it lasts.
Your Talent Stack
Stack a few skills you are merely good at and see how rare the combination really is.
Deep Work Budget
How many genuine focus hours survive your interruptions, per week and per year.
Does This Skill Pay Off?
Weigh the hours to learn a skill against the time it saves, and find the break-even.
Deliberate Practice Planner
Turn a goal and your weekly time into weeks, sessions, and a finish date.
Plan It Backwards
Get the milestones for a goal by working backwards from its deadline.
Your Reading Diet
A few minutes a day, in books per year, and how many you have left in a lifetime.
Sleep & Your Brain
What short nights really cost your focus, memory, and judgment.
Mastery Hours
How long deliberate practice takes to reach 20, 1,000, and 10,000 hours.
Spaced Repetition
A review schedule that beats the forgetting curve so learning sticks.
1% Compounding
What getting 1% better (or worse) every day does over a year.
AI & LLMs
Can I run this LLM? (VRAM)
GPU memory a model needs, whether it fits your card, and how many GPUs. With a shareable result card.
Token Counter & Cost
Estimate tokens and cost across GPT, Claude, Gemini, GLM-5.2, DeepSeek and more.
LLM Comparison
The major models side by side: price, context, parameters, open vs closed. Sortable.
Head-to-Head (X vs Y)
Pick any two models for a focused side-by-side comparison.
LLM Cost Calculator
What an AI feature costs per finished task, comparing two models.
Agent Cost Simulator
Cost per finished task across multi-step loops, carried context, and retries.
Coding Agent Cost Split
Plan high, execute cheap: how much you save by running the grind loop on a cheaper model.
Self-Host vs API
Should you run an open model yourself or pay per token? Find the break-even.
MCP Server Directory
The most useful Model Context Protocol servers, grouped by what they do.
Startup & founder
Equity & Dilution
What your ownership becomes after seed, A, B and an option pool, and its value at exit.
Runway & Burn
Net burn, months of runway, and when to start raising.
SaaS Metrics
ARR, LTV, LTV:CAC, CAC payback, and the Rule of 40.
Stock Option Value
What your options clear after exercise across exit prices.
Engineering
Life & you
Wheel of Life
Rate eight areas of your life and see the balance at a glance.
Financial Independence (FIRE)
Your "enough" number and the years until work is optional.
How Rich Are You, Really?
Where your income lands among everyone alive.
How You Spend Your Life
The years you give to sleep, work, screens, and what is left.
The Tail End
How many times you may have left with someone you love.
Big questions
Your Life in Weeks
Your whole life as a grid of weeks, lived and remaining.
Exponential Intuition
Fold a paper to the Moon and feel why exponentials break the brain.
The Birthday Paradox
Why just 23 people make a shared birthday likely.
Drake Equation
Estimate how many civilizations might be out there.
Kardashev Scale
Rank a civilization by the energy it can harness.
Cosmic Calendar
All 13.8 billion years of time compressed into one year.
p(doom) Estimator
Turn your assumptions about AI risk into a rough probability.