Misc Calculators

Compute tip and split a restaurant bill evenly among diners.

Annual fuel cost (gas car) vs annual electricity cost (EV) for the same mileage.

Cost per session: kWh delivered × $/kWh, accounting for charger efficiency.

System cost / annual savings = years to break even on a residential solar install.

30-year comparison: ownership equity + appreciation vs rent + alternative-investment growth.

Lifetime income premium vs total cost (tuition + 4 years of foregone earnings).

Target salary / billable hours = required hourly rate.

(Target salary + overhead + profit margin) / billable hours = full freelance hourly rate.

LTV / CAC ratio. Healthy SaaS: 3:1+; under 1:1 burns money.

Conv % = target revenue / (visitors × avg order value).

Sends × open rate × CTR × conv × AOV → revenue. Compare to send cost.

Revenue = (downloads / 1000) × CPM × ad slots.

Render time = (duration × frames/sec × complexity) / machine speed.

Compare AWS S3 / B2 / R2 / Glacier monthly + retrieval costs.

Recouped = monthly savings × months you keep it cancelled.

Convert numbers between hexadecimal, binary, octal, and decimal. Shows the bit pattern grouped by nibble + the two’s-complement representation for negative values.

Look up the ASCII/Unicode codepoint for any character — or go the other way and turn a list of codepoints back into text. Shows decimal, hex (U+XXXX), octal, binary, HTML entity, JS escape, and URL-encoded forms for every code point.

Count words, characters, paragraphs, and sentences in any pasted text, plus reading time at 250 / 200 / 150 WPM.

Generate placeholder text — paragraphs, sentences, or words — in deterministic seeded form. Starts with the classic "Lorem ipsum dolor sit amet" opening.

Estimate password entropy in bits and the time an offline brute-force attacker would need at common cracking rates. Pure client-side — your password is never sent anywhere.

Generate strong, deterministically-seeded passwords. Pick length, character classes, and bulk-count. All client-side — passwords never leave the browser.

Build the canonical text payload encoded in a QR code — plain text, URL, WiFi-network credentials, or vCard contact. Includes a ready-to-render image URL for visual scanning.

Validate a barcode number, compute the check digit, and produce a ready-to-render image URL. Supports EAN-13, EAN-8, UPC-A, Code 128, and ISBN.

Convert a color between hex, RGB, HSL, HWB, and CMYK. Reports relative luminance and WCAG 2.2 contrast ratio against white and black.

Resize an image to a target dimension while preserving aspect ratio. Reports the GCD-simplified ratio (16:9, 4:3 …) and total megapixels.

Encode a string for use inside a URL (or decode percent-escapes back to text). Shows component vs full-URI variants and base64url for token use.

Size a solar array from daily kWh use and peak sun hours, and size an off-grid battery bank by autonomy days and depth of discharge.

Calculate how much chlorine to add to raise free chlorine from current to target ppm, for liquid bleach, cal-hypo, dichlor, or trichlor products.

Calculate aquarium volume in gallons and litres from tank dimensions — rectangular, cube, cylinder, hexagonal, or bow-front shapes.

Find the final price after a percentage discount and sales tax, with a full breakdown of savings and tax added.

Work the exposure triangle: enter aperture, shutter speed, and ISO to get the EV, or solve for the aperture or shutter that hits a target EV.

Calculate near and far depth-of-field limits and the hyperfocal distance from focal length, aperture, focus distance, and sensor size.

Compute uncompressed PCM audio bitrate and file size per minute from sample rate, bit depth, and channel count.

Estimate video file size from bitrate and duration, or get a recommended bitrate from resolution and frame rate using a bits-per-pixel target.

Estimate image file size by format and quality (JPEG, PNG, WebP, AVIF) from width and height, using typical bits-per-pixel figures.

Convert between satoshis and bitcoin (1 BTC = 100,000,000 sats) and optionally value either in US dollars at a given BTC price.

Estimate an Ethereum transaction fee from the gas price in gwei, the gas units used, and the ETH price in dollars.

Estimate the energy a solar array produces from its wattage, peak sun hours, a system derate, and the number of days.

Estimate how long it takes to charge an electric vehicle from one state of charge to another, and what the electricity costs.

Find your Western (tropical) zodiac sign and your Chinese zodiac animal and element from your birth date.

Find which generation a birth year belongs to — Silent, Boomer, Gen X, Millennial, Gen Z, or Gen Alpha — with the reference year ranges.

Calculate traditional East Asian "lunar" age, where you are one year old at birth and gain a year each new year.

Reduce your birth date to a numerology life path number (1–9, plus master numbers 11, 22, 33) with a short meaning.

Compute a US business-travel per diem from the lodging and M&IE rates, applying the GSA 75% first-and-last-day meal rule.

Estimate a wedding’s total cost from guest count, per-guest catering, venue, and the major extra categories, with a per-guest breakdown.

Plan a trip budget from lodging, daily food, transport, and activities — with totals per person and per day for any number of travelers.

Check the contrast ratio between a text color and background and whether it passes WCAG AA and AAA for normal and large text.

Convert a color between HEX, RGB, and HSL formats, with the parsed channel values and CSS-ready strings.

Generate a responsive CSS clamp() value that scales smoothly between a minimum and maximum size across a viewport range.

Convert a Unix timestamp (seconds or milliseconds) to a human-readable UTC and local date and time, with relative time.

Generate a harmonious color palette — complementary, analogous, triadic, tetradic, or monochromatic — from a base color.