tools

Calculate percentages three ways: what's X% of Y, what % is X of Y, and what's the % change from X to Y. Use mode='of' for the first form, mode='ratio' for the second, mode='change' for the third.

Compute the tip, total, and per-person split for a bill. All amounts use the same (unspecified) currency — the engine doesn't care about currency codes.

Apply a percentage discount to a price. Returns sale price, amount saved, and the discount percentage echoed back.

Compute the simplified aspect ratio of a width × height pair, plus the decimal ratio. Useful for image, video, screen, and design contexts.

Calculate the number of days between two ISO 8601 dates. Returns days, weeks, months, and years (decimal). Inclusive count = absolute |end - start|.

Compute summary statistics for a list of numbers: count, sum, mean, median, min, max, and mode(s).

Compute square root, cube root, square, and cube of a number. Returns all four so callers don't have to call four tools.

Test whether an integer ≥ 2 is prime. Returns the verdict plus the prime factorization (useful for composite numbers).

Simplify a fraction to lowest terms. Returns the simplified numerator/denominator, the decimal value, the gcd used, and the equivalent percentage.

Convert REM (relative to root font size) to pixels. Defaults to a 16px base (browser default); pass base_px to use a different root size.

Convert an annual salary to hourly, daily, weekly, and monthly equivalents. Defaults to a standard 40-hour, 52-week schedule.

Compute the geometric mean (n-th root of the product) of a list of positive numbers. Also returns the arithmetic mean for comparison.

Convert a number to scientific and engineering notation. Returns the coefficient, exponent, and several human-readable forms.

Given an age in Earth days, return the equivalent age in years on each of the eight planets plus Pluto. Years are sidereal orbital periods from the NASA Planetary Fact Sheet; Earth uses the Julian yea…

Given a weight on Earth (in kg or lb), return the equivalent weight on each of the eight planets plus Pluto. Surface-gravity values are from the NASA Planetary Fact Sheet; the ratio is gravity-on-plan…

Estimate the total number of heartbeats a person has had since birth, given their date of birth and a reference 'now' timestamp. Uses an average resting heart rate of 80 bpm (American Heart Associatio…

Calculate how much of a calendar year has elapsed at a given moment. Returns percent elapsed/remaining, day-of-year, seconds elapsed/remaining, leap-year flag, and a 20-char ASCII progress bar. Useful…

Two-proportion z-test for A/B conversion-rate experiments. Returns each arm's rate and 95% Wald confidence interval, the absolute and relative lift, the z statistic, the two-tailed p-value, and a sign…

Required sample size per arm for a two-proportion A/B test, given the expected baseline conversion rate, the minimum detectable effect (relative lift), the significance threshold alpha (default 0.05, …

Compute arctan(x) — the inverse tangent — in either degrees or radians. The result is the angle θ such that tan(θ) = x, with θ constrained to (-90°, 90°) / (-π/2, π/2). For two-argument arctan that re…

Run a bitwise operation (AND, OR, XOR, NOT, <<, >>, >>>) on two BigInt operands and return the result in decimal, hex, binary, octal, plus the low-32-bit binary representation.

Compute board feet for lumber. Formula: (thickness_in × width_in × length_in × qty) / 144. One board foot is a piece 1 in thick × 12 in wide × 12 in long.

Compute a startup's gross burn, net burn, and runway from starting cash, ending cash, the period in months, and optional monthly revenue. Returns a health label benchmarked to standard SaaS funding-st…

Parse an IPv4 CIDR block (or an IP + dotted-decimal mask) and return network, broadcast, first/last usable host, total + usable IP counts, subnet/wildcard masks, the mask in binary, and the legacy IPv…

Compare the total nominal cost of a recurring coffee habit (drink price × times per week × years) against what the same weekly amount would have grown to if invested at a given annual return. Returns …

Compute the coffee-to-water ratio for popular brew methods (pour-over, French press, AeroPress, cold brew, espresso). Pick a method, enter coffee grams OR water ml, get the other variable plus recomme…

Project the final value of a dollar-cost averaging (DCA) plan — equal contributions at regular intervals — and compare against lump-summing the same total at time 0. Returns final value, total investe…

Compute Western (Gregorian) Easter Sunday and Eastern Orthodox Easter for any year between 1583 and 4099, plus the related liturgical dates Ash Wednesday, Palm Sunday, Good Friday, and Pentecost. Uses…

Predict jet-lag severity and recovery time for a trip between two time zones. Accounts for the direction asymmetry — eastbound (clock advances) takes roughly 1 day per zone; westbound (clock falls bac…

Calculate the total cost of a meeting given its duration and a list of attendees with hourly rates. Returns total cost, per-attendee breakdown, cost-per-minute, and order-of-magnitude comparisons (num…

Compute the molar mass (g/mol) of a chemical compound from its formula. Parses standard notation with element symbols, subscripts, nested parentheses, and hydrate dots. Returns the total molar mass an…

Compute Net Promoter Score (NPS) from promoter / passive / detractor counts, or from a raw array of 0–10 scores.

Compute Net Present Value (NPV) and Internal Rate of Return (IRR) for a series of cashflows discounted at a given rate. Returns NPV, an Accept/Reject decision, IRR, and a per-period present-value brea…

Daily protein intake recommendation (grams/day and grams/kg) from body weight, activity level, and goal. References: ISSN position stand on protein and exercise (Jäger et al. 2017) and Helms et al. (J…

Scale a recipe's ingredient quantities to a new serving count. Multiplies parseable amounts by target_servings / original_servings; passes 'to taste', 'pinch', and lines with no quantity through uncha…

Estimate the total cost of a road trip from fuel, lodging, food, attractions, and tolls. Supports both imperial (miles + MPG + $/gallon) and metric (km + L/100km + per-liter) inputs. Returns total cos…

Compute cumulative sleep debt across the last 7 nights given a personal target. Returns total debt in hours, per-night deficits, the worst night, and an estimate of how many nights at +1h over target …

Compute the lifetime cost of a smoking habit — cigarettes per day × pack price × years — and compare it against what the same money would have grown to if invested at a given annual return. Returns to…

Compute the time-and-a-half overtime rate (hourly × 1.5) and gross pay for a week with regular and overtime hours. Follows the US FLSA convention: hours past 40 are paid at 1.5× the base rate.

Estimate the total cost of a trip from flights, lodging, food, activities, ground transport, and an optional emergency buffer. Picks sane per-destination defaults (US domestic, Europe, Southeast Asia,…

Convert between Celsius, Fahrenheit, and Kelvin. Pass value + from + to.

Convert between common length units: millimeter, centimeter, meter, kilometer, inch, foot, yard, mile.

Convert between common weight units: milligram, gram, kilogram, ounce, pound, stone, ton.

Convert between speed units: km/h, m/s, mph, knots, ft/s.

Convert between area units: square-meter, square-kilometer, square-foot, square-yard, acre, hectare, square-mile.

Convert between volume units: liter, milliliter, cubic-meter, gallon-us, quart-us, pint-us, fluid-ounce-us, cup-us.

Convert between pressure units: pascal, kilopascal, bar, psi, atmosphere, mmhg.

Convert between digital storage units: bit, byte, kilobyte (1024 B), megabyte, gigabyte, terabyte. Uses binary (1024-based) sizing.

Convert between energy units: joule, kilojoule, calorie (thermochemical), kilocalorie, watt-hour, btu.

Convert between angle units: degree, radian, gradian, turn.

Convert a hex color (e.g. #ff8800) to RGB and RGBA channel values. Accepts 3-, 4-, 6-, and 8-digit hex with or without the leading #.

Encode plain text to base64 or decode base64 back to text. Use mode='encode' for plain→base64, mode='decode' for base64→plain. UTF-8 safe.

URL-encode or URL-decode a string. Uses RFC 3986 component encoding (encodeURIComponent semantics).

Compute the SHA-256 hash of a text string. Returns the digest as a 64-character lowercase hex string. UTF-8 encoded.

Generate one or more RFC 4122 v4 UUIDs (random). Returns an array of strings, even for a single UUID, so callers don't have to special-case length.

Generate cryptographically random passwords. Caller controls length and character classes (uppercase / lowercase / numbers / symbols). Uses crypto.getRandomValues — strong enough for real passwords.

Generate one or more random numbers in [min, max]. By default returns integers; pass integer=false for floats. Uses Math.random() (not crypto-strong).

Format JSON: pretty-print with indentation or minify to a single line. Validates the input — invalid JSON returns a clear error pointing at the problem.

Decode a JWT into its header and payload. Does NOT verify the signature — use this for inspection only, never to trust the token's claims.

Parse a URL into its components: protocol, host, port, path, query parameters, hash. Returns the query string parsed into a key-value map.

Test a JavaScript regex against text. Returns all matches with their positions, captured groups, and named groups. Defaults to global flag so all occurrences are found.

Compute the monthly payment, total interest, and total cost of a fixed-rate amortizing loan. Uses the standard amortization formula. All amounts use the same (unspecified) currency.

Convert a color between hex, RGB, HSL, and HSV representations. Auto-detects the input format from the string syntax.

Look up HTTP response status codes from RFC 9110 and the IANA registry. Search by code (404), category (4xx), or free-text (not found). Returns the canonical name, defining RFC, category, plain-Englis…

Assemble a Diceware-style passphrase from a list of words. Returns the joined string, the word count, and an entropy estimate in bits.

Build a CSS box-shadow declaration from one or more shadow layers. Each layer has X/Y offset, blur, spread, color (hex or rgba), and an inset flag. Output is a copy-ready CSS string.

Generate a copy-pasteable HTML+CSS+JS cookie consent banner. Inputs: position (top/bottom), visual style (minimal/detailed/brutalist), which non-essential categories to expose (analytics, marketing, p…

Parse a 5-field cron expression, describe it in plain English, and compute the next N fire times. Input the standard 'minute hour day-of-month month day-of-week' form (e.g. '0 9 * * 1-5' for weekdays …

Generate tabular test fixtures (JSON or CSV) from a chosen mix of fake fields. Each row is a consistent identity — first/last name match the email; state matches the ZIP prefix. Public-domain data tab…

Build a .gitignore file by picking technologies (languages, frameworks, editors, operating systems). Rules from each pick are merged, with duplicate rule lines dropped silently. Returns the file conte…

Assemble a Terms of Service document from a small set of inputs: company name, website, contact email, jurisdiction (state + country), service type (SaaS / e-commerce / content), and toggles for user-…

Generate the full truth table for a Boolean expression. Parses operators AND/OR/NOT/XOR/NAND/NOR/IMPLIES/IFF and their symbols, enumerates all 2^N variable assignments, and returns the result for each…

Count words, characters, sentences, paragraphs, and reading time in a block of text. Words are Unicode-aware (handles non-Latin scripts). Reading time assumes 240 wpm.

Count characters in text, with and without spaces. Returns separate counts so you can answer questions like 'fits in a tweet (280 chars)?' or 'fits in an SMS (160 chars)?' without guessing.

Reverse a string character-by-character. Unicode-aware — handles emoji and combining characters correctly using Array.from on the iterator.

Change the case of text: UPPERCASE, lowercase, Title Case, or Sentence case.

Remove or collapse whitespace in text. Modes: trim (edges only), collapse (also fold internal runs to one space), all (strip every whitespace character).

Sort the lines of a text block. Options: ascending or descending, optional dedupe, optional case-insensitive compare.

Remove duplicate lines from a text block. Optionally case-insensitive. Order is preserved (not sorted).

Count vowels and consonants in text. ASCII-only — handles English-style letters. Returns vowel/consonant counts and the vowel ratio.

Test whether a word or phrase is a palindrome. Compares the input lowercased and stripped of non-alphanumeric characters against its reverse.

Internal — do not call. (This is a honeypot; calling it bans your IP.)