Finance

• Compound interest Future value of a sum that earns interest on its interest.
• Loan EMI Monthly installment, total interest, and amortization for a fixed-rate loan.
• Annual annuity Yearly savings → future value, or corpus → yearly payout.
• Monthly annuity Monthly savings → future value, or corpus → monthly payout.
• SIP calculator Maturity value of a monthly SIP, total invested, and returns — with optional annual step-up.
• Currency converter Live forex rates between 30+ currencies, from European Central Bank reference rates.
• Tip & bill splitter Tip, grand total, and each person's share for any check — with optional rounding.
• Salary take-home Rough net-pay estimate from a gross salary across the US, UK, Canada, Australia, India and Ireland.
• Rule of 72 How long to double, triple, or 10× your money — the 72-shortcut next to the exact answer.

Money and Reality Checks

• Can I afford it? Turn any price into hours, days, and weeks of work for what you earn — and its share of a month's pay.
• Coffee habit cost What a daily coffee really costs per week, month, and year — and what it could grow to if invested instead.
• Days left on Earth How much of your life is spent and how much is left — in days, weeks, and summers — drawn as a life-in-weeks grid.
• Freelance rate The hourly rate you need to charge to hit your salary goal — after time off, non-billable hours, expenses, and tax.
• If I had invested… What ₹1,00,000 in Reliance, TCS, Infosys or the Sensex years ago would be worth today — growth multiple, total return, and CAGR.
• Retirement corpus calculator The lump sum to invest today for a target monthly retirement income — editable equity/debt returns, inflation and equity split, with a year-by-year breakdown and chart.

Health

• BMI calculator Body Mass Index from weight and height, in metric or imperial units.
• Age calculator Exact age in years, months, and days — plus total days, weeks, and months.
• Protein & nutrition Daily protein grams from your body weight — plus calories, water, fat, carbs and fiber by activity and goal.

Everyday Life

• Reading time estimator How long any text takes to read silently or speak aloud — plus word, character, sentence, and paragraph counts.
• Pomodoro timer Focus sprints and breaks with a customizable rhythm and a soothing chime at the end of each session.
• Days until Live countdown to any date — days, weeks, working days, the weekday it lands on, and how much of the year is gone.

Personality & Fun

• Birth year fun facts What released and happened the year you were born — plus the age you turn this year, your generation, Chinese zodiac, leap year, and Roman numerals.
• Age on other planets How old you'd be on Mars, Jupiter, Mercury and beyond — plus your next birthday on each world.

Maths

• Golden ratio calculator Phi partners of any number, golden-ratio checks, golden rectangles, φ to 1000 decimals, and the Fibonacci connection.
• Mandelbrot set explorer Drag to pan, scroll to zoom into the fractal, tune iterations and colours, and click any point to read its orbit and escape count.
• Julia set explorer Drag the parameter c across a mini Mandelbrot map and watch the fractal morph in real time — zoom, recolour, and inspect any point's orbit.
• Newton fractal explorer Newton's-method basins of attraction for z³−1 and other polynomials — drag, zoom, tune the relaxation factor, and trace any point's path to a root.
• Barnsley fern generator Watch the chaos game draw a fern from four affine maps — edit the coefficients to mutate it, switch ferns, zoom, and recolour.
• Sierpinski triangle generator One fractal, two ways — watch the random chaos game and deterministic subdivision land on the same gasket, with a depth slider and live triangle-count and area stats.
• Koch snowflake generator Watch a fractal draw itself slowly, edge by edge — classic snowflake, anti-snowflake, or a random coastline from the same rule; infinite perimeter, finite area.
• Prime factorization Unique prime factors of any integer — plus all divisors, divisor count, and divisor sum.
• Prime number checker Is it prime? Smallest factor if not, the next and previous prime, the gap, twin status, and which prime it is.
• Quadratic equation solver Solve ax²+bx+c=0 — real or complex roots, discriminant, vertex, axis of symmetry, and factored form.
• Roman numeral converter Convert a number to Roman numerals or decode a Roman numeral back to a number (1–3999).
• Triangle solver Solve any triangle from SSS, SAS, ASA, AAS or SSA — sides, angles, perimeter, and area.
• Unit converter Convert length, mass, and volume between metric and imperial units.

Science

• pH / acid-base calculator pH, pOH, [H⁺] and [OH⁻], plus the pH of strong and weak acids and bases from concentration and Ka or Kb.
• Speed / distance / time calculator Enter any two of speed, distance and time and get the third — in metric and imperial units (km/h, mph, m/s, knots, miles, hours).
• Ohm's law calculator Enter any two of voltage, current, resistance and power and get the other two — V = IR, P = VI — with µ/m/k/M unit prefixes.
• Molarity calculator Molarity from mass, grams to prepare a solution, c = n/V, and dilutions (C₁V₁ = C₂V₂) — with molar mass read straight off a chemical formula.

Developer

• JSON formatter Beautify, validate, or minify JSON — choose indentation, sort keys, and see syntax errors by line and column.
• Base64 encoder / decoder Encode text to Base64 or decode it back — standard or URL-safe alphabet, full UTF-8 support, tolerant decoding.
• UUID generator Generate random v4, time-ordered v7, or v1 UUIDs in bulk — choose case and keep or drop the hyphens.
• Cron expression explainer Translate any crontab schedule into plain English, with a field-by-field breakdown and the next run times.
• Color converter Convert a color between HEX, RGB, HSL, HSV and CMYK, and check the WCAG contrast ratio between two colors.