Every tool you need, in one place

💰

PennyPath

Personal-finance calculators — compound interest, loans, mortgage payoff, debt payoff, FIRE and more.

Finance

🌅

Golden Hour Calculator

Sunrise, sunset, golden & blue hour and moon phase for any place and date.

Everyday

🛂

Schengen 90/180 Calculator

Track your Schengen days and see how long you can still stay.

Time

☕

Caffeine Calculator

Caffeine in your body over time — and when to stop coffee for better sleep.

Health

❄️

BTU Calculator

The right air-conditioner or heater size for any room.

Home

🌱

Planting Calendar

Frost dates and a vegetable planting calendar by USDA hardiness zone.

Home

🎉

Catering Calculator

How much food, drinks, ice and cake to serve for your party guests.

Everyday

📏

Size Converter

Shoe, clothing and ring sizes across US, EU, UK and more.

Converter

📅

Business Days Calculator

Working days between dates, excluding weekends and public holidays.

Time

🎓

Final Grade Calculator

The grade you need on the final, plus weighted-grade and GPA.

Math

🚗

Road Trip Cost Calculator

Estimate trip fuel cost and compare gas vs EV.

Everyday

🔢

Percentage Calculator

Percent of a number, percent change, and increase or decrease.

Math

🎂

Age Calculator

Your exact age in years, months and days — plus days to your next birthday.

Time

🧾

Tip Calculator

Tip and split a bill, with per-person totals and country tipping norms.

Finance

🎨

Paint Calculator

How much paint a room needs, by dimensions, coats and coverage.

Home

📝

Word Counter

Words, characters, sentences and reading time — private, in your browser.

Dev

📆

Date Duration Calculator

Days, weeks and months between any two dates.

Time

⏳

Countdown Timer

Live countdown to any date — with a link you can share.

Time

🏷️

Discount Calculator

Sale price, savings and stacked discounts.

Finance

🥄

Cooking Converter

Cups, grams, ml and tablespoons for any ingredient.

Converter

💧

Water Intake Calculator

How much water to drink a day for your weight and activity.

Health

🔠

Text Case Converter

Upper, lower, title, sentence, camelCase, snake_case and more.

Dev

🎲

Random Picker

Random numbers, dice, coin flips and random name draws.

Everyday

🧱

Material Calculator

Mulch, soil, gravel and concrete by volume.

Home

☕

Coffee Ratio Calculator

Coffee-to-water ratio in grams for any brew.

Everyday

😴

Sleep Calculator

Best bedtimes and wake times by 90-minute cycles.

Health

🏛️

Roman Numeral Converter

Convert numbers to Roman numerals and back.

Converter

🖥️

PPI / Screen Calculator

Pixels per inch, dot pitch and aspect ratio for any screen.

Dev

🍳

Recipe Scaler

Scale recipe servings and ingredient amounts up or down.

Everyday

🏋️

One-Rep Max Calculator

Estimate your 1RM and load the barbell, plate by plate.

Health

🌍

Time Zone Converter

See the time across cities and plan meetings across zones.

Time

🌡️

Oven Temp Converter

°F, °C, Gas Mark, fan oven and air fryer.

Converter

📊

Statistics Calculator

Mean, median, mode and standard deviation.

Math

🛒

Unit Price Calculator

Compare cost per unit to find the best value.

Finance

⚡

Electricity Cost Calculator

What an appliance costs to run per day, month and year.

Home

✈️

Jet Lag Calculator

Recovery time and adjustment tips by time zones crossed.

Time

💲

Sales Tax Calculator

Sales tax by US state, with totals and reverse price.

Finance

👶

Due Date Calculator

Estimate your pregnancy due date and milestones.

Health

📚

Citation Generator

APA, MLA and Chicago citations from your source.

Everyday

⏱️

Pomodoro Timer

25-minute focus sessions with breaks.

Time

📖

Reading Speed Test

Measure your reading speed in words per minute.

Everyday

🧳

Packing List Generator

A categorized travel checklist for any trip.

Everyday

🐾

Pet Age Calculator

Dog and cat years in human years.

Everyday

💎

Birthstone Finder

Your birthstone, birth flower and zodiac sign.

Everyday

🗓️

Your Life in Weeks

See your life as a grid of weeks — lived and ahead.

Time

⚖️

BMI & Calorie Calculator

BMI, BMR and daily calories (TDEE).

Health

🌈

Color Converter

HEX, RGB, HSL and a WCAG contrast checker.

Dev

🔁

Unit Converter

Length, weight, temperature, volume and more.

Converter

🏃

Running Pace Calculator

Pace, time, distance and race finish times.

Health

🧩

JSON Formatter

Beautify, validate and minify JSON in your browser.

Dev

📡

Morse Code Translator

Translate text to Morse code and back.

Dev

🔑

Password Generator

Strong random passwords, generated privately.

Dev

🔤

Base64 Encode / Decode

Encode and decode Base64 text in your browser.

Dev

🕒

Time Card Calculator

Add up work hours and pay from clock-in/out.

Time

🔡

Number to Words

Spell out numbers and check amounts.

Converter

📄

Lorem Ipsum Generator

Placeholder text by paragraphs, sentences or words.

Dev

⌨️

Typing Speed Test

Measure your typing speed and accuracy.

Everyday

⛽

Gas Mileage Calculator

MPG, cost per mile and L/100km.

Everyday

🍽️

Macro Calculator

Daily protein, carbs and fat from your calories.

Health

🔗

URL Slug Generator

Turn any title into a clean URL slug.

Dev

🎚️

CSS Gradient Generator

Design a gradient and copy the CSS.

Dev

🆔

UUID Generator

Random v4 UUIDs, one or in bulk.

Dev

🔍

Text Diff Checker

Compare two texts and see what changed.

Dev

💦

Dew Point Calculator

Dew point and comfort from temp & humidity.

Home

🌫️

CSS Box Shadow Generator

Design a shadow and copy the CSS.

Dev

🔥

Calories Burned Calculator

Calories burned by activity and time.

Health

⏰

Unix Timestamp Converter

Epoch time to date and back, plus the live timestamp.

Time

⏲️

Online Timer & Stopwatch

Countdown timer and stopwatch with alarm.

Time

🔣

HTML Entity Encoder

Escape and unescape HTML special characters.

Dev

💻

Number Base Converter

Binary, decimal, hexadecimal and octal.

Converter

🔊

Text to Speech

Read any text aloud with browser voices.

Dev

🔎

Regex Tester

Test and debug regular expressions live.

Dev

⚙️

Cron Expression Generator

Build and explain cron schedules.

Dev

📐

Aspect Ratio Calculator

Resize dimensions and simplify ratios.

Dev

🧮

Bill Splitter

Split a bill evenly or by share, with tip.

Finance

✍️

Markdown Preview

Live Markdown to HTML.

Dev

🌐

Subnet Calculator

IPv4 CIDR, mask and host range.

Dev

🔧

PX to REM Converter

px, rem, em and pt for CSS.

Dev

#️⃣

Hash Generator

SHA-256, SHA-1 and SHA-512 hashes.

Dev

🔐

JWT Decoder

Decode a JSON Web Token's header and payload.

Dev

🔃

Sort Text Lines

Sort, dedupe, reverse and clean lists.

Dev

💍

Anniversary Calculator

Time together, milestones and traditional gifts.

Time

🔄

JSON ⇄ CSV Converter

Convert JSON arrays to CSV and back.

Dev

🧭

URL Encoder / Decoder

Percent-encode text and parse URLs.

Dev

🧾

VAT Calculator

Add or remove VAT/GST at any rate.

Finance

📈

Margin & Markup Calculator

Profit margin, markup and pricing.

Finance

➗

Fraction Calculator

Add, subtract, multiply and divide fractions.

Math

✖️

Quadratic Equation Solver

Solve ax²+bx+c=0 with steps.

Math

📐

Area Calculator

Area of rectangles, circles, triangles and more.

Math

🗂️

Word Frequency Counter

Most-used words and keyword density.

Dev

🖼️

Image to Base64

Encode an image to a data URI.

Dev

🎡

Spin the Wheel

Random picker wheel for names and choices.

Everyday

🎵

Online Metronome

Steady BPM click for practice.

Everyday

🔺

Right Triangle Calculator

Pythagorean theorem, sides and angles.

Math

🔢

Ratio Calculator

Solve, simplify and scale ratios.

Math

📱

What Is My Browser?

Your browser, screen size and device info.

Dev

🎓

GPA Calculator

Weighted GPA from courses and credits.

Math

🔥

TDEE Calculator

Daily calorie needs and BMR.

Health

🪨

Gravel Calculator

How much gravel or material you need.

Home

🏠

Mortgage Calculator

Monthly payment, interest and total cost.

Finance

⚖️

BMI Calculator

Body Mass Index and weight category.

Health

🧱

Concrete Calculator

Concrete volume and bags needed.

Home

🔐

Chmod Calculator

File permissions: octal, symbolic, command.

Dev

🔌

Resistor Color Code

Decode 4- and 5-band resistor bands.

Math

🧪

Dilution Calculator

Solve C1V1 = C2V2 for dilutions.

Math

📈

Compound Interest

Project savings growth over time.

Finance

🚗

Car Loan Calculator

Monthly auto loan payment and interest.

Finance

⚡

Ohm's Law Calculator

Voltage, current, resistance and power.

Math

🔑

Password Strength Checker

Entropy and crack time, in your browser.

Dev

⏱️

Hours Calculator

Time between two times, minus breaks.

Time

⚗️

Molar Mass Calculator

Molecular weight of any formula.

Math

🔢

Number Base Converter

Convert between base 2–36, bin/oct/hex.

Converter

➗

LCM & GCD Calculator

Least common multiple and divisor.

Math

💹

ROI Calculator

Return on investment and annualized ROI.

Finance

📏

Body Fat Calculator

Body fat % via the Navy method.

Health

🌡️

Temperature Converter

Celsius, Fahrenheit and Kelvin.

Converter

🥵

Heat Index Calculator

"Feels like" temp from heat & humidity.

Home

🥶

Wind Chill Calculator

"Feels like" cold from wind & temp.

Home

🧱

Tile Calculator

How many tiles and boxes you need.

Home

⚖️

Ideal Weight Calculator

Ideal body weight and healthy range.

Health

💵

Hourly to Salary

Hourly, weekly, monthly and annual pay.

Finance

🔬

Scientific Notation

Convert to and from scientific notation.

Math

📄

Words to Pages

How many pages a word count fills.

Everyday

🎲

Random Number Generator

Random numbers in any range.

Everyday

👟

Steps to Miles

Convert steps to miles and kilometers.

Health

📐

Slope Calculator

Slope, angle and line equation.

Math

♌

Zodiac Sign Calculator

Your star sign and Chinese zodiac.

Everyday

🏷️

Discount Calculator

Sale price, savings and percent off.

Finance

🚀

Speed, Distance & Time

Solve for speed, distance or time.

Math

🧊

Density Calculator

Solve density, mass or volume.

Math

√

Square Root Calculator

Find and simplify square roots.

Math

🔢

Exponent Calculator

Raise any base to any power.

Math

🪵

Board Foot Calculator

Board feet of lumber and cost.

Home

🏠

Roof Pitch Calculator

Pitch, angle and rafter length.

Home

🔟

Prime Number Checker

Is it prime? Plus factorization.

Math

⭕

Circle Calculator

Radius, diameter, circumference, area.

Math

🔀

Permutations & Combinations

nCr and nPr for n and r.

Math

📉

Logarithm Calculator

Log of any base, plus ln and log2.

Math

🪜

Stair Calculator

Risers, tread depth and step count.

Home

🚧

Fence Calculator

Posts, panels, rails and pickets.

Home

❗

Factorial Calculator

Exact n! for any integer.

Math

🌀

Fibonacci Calculator

Sequence and the Nth term.

Math

⚗️

Molarity Calculator

Moles, liters and concentration.

Math

🌾

Acreage Calculator

Land area in acres and more.

Home

🧱

Drywall Calculator

Sheets and compound you need.

Home

➗

Modulo Calculator

Remainder, quotient and mod.

Math

📉

Percent Error Calculator

Error between measured and true.

Math

📊

Z-Score Calculator

Z-score and percentile.

Math

🧻

Wallpaper Calculator

How many rolls you need.

Home

🪴

Soil Calculator

Soil volume for beds and gardens.

Home

🛢️

Cylinder Volume Calculator

Volume, surface area and capacity.

Math

½

Decimal to Fraction

Convert decimals to simplified fractions.

Converter

🏘️

Rent vs Buy Calculator

Compare renting versus buying.

Finance

💲

Simple Interest Calculator

Interest and total from P, r, t.

Finance

🥩

Protein Intake Calculator

Daily protein needs by weight.

Health

📅

Week Number Calculator

What ISO week of the year it is.

Time

🐸

Leap Year Calculator

Is a year a leap year?

Time

💍

Ring Size Converter

US, UK, EU and mm ring sizes.

Converter

💾

Data Storage Converter

Bytes, KB, MB, GB, TB.

Converter

⚖️

Weight Converter

kg, lb, oz, grams and stone.

Converter

📏

Length Converter

cm, inches, meters, feet, miles.

Converter

📐

Angle Converter

Degrees, radians and gradians.

Converter

🎚️

Pressure Converter

psi, bar, kPa, atm and mmHg.

Converter

☢️

Half-Life Calculator

Decay, remaining amount and λ.

Math

⚗️

Percent Yield Calculator

Reaction yield from actual vs theoretical.

Math

❤️

Heart Rate Zone Calculator

Max heart rate and training zones.

Health

📐

Trigonometry Calculator

sin, cos, tan and inverses.

Math

⚖️

Break-Even Calculator

Break-even units and revenue.

Finance

🏎️

Speed Converter

mph, km/h, m/s, knots, Mach.

Converter

🌱

Grass Seed Calculator

Seed needed for a lawn.

Home

📏

Waist-to-Hip Ratio

WHR and health-risk category.

Health

⏰

Overtime Pay Calculator

Time-and-a-half and total gross.

Finance

⏳

Time Converter

Seconds, minutes, hours, days, years.

Converter

🪵

Decking Calculator

Deck boards, joists and screws.

Home

🎲

Dice Roller

Roll d4–d100 with notation.

Everyday

🥤

Volume Converter

Liters, gallons, cups, fl oz, mL.

Converter

💰

Net Worth Calculator

Assets minus liabilities.

Finance

🧶

Carpet Calculator

Carpet in sq ft and sq yards.

Home

🪙

Coin Flip

Heads or tails, online.

Everyday

🧪

Ideal Gas Law Calculator

Solve PV = nRT.

Math

🟩

Area Converter

sq ft, sq m, acres, hectares.

Converter

🧮

Weighted Average Calculator

Average of values with weights.

Math

🎯

Savings Goal Calculator

How much to save each month.

Finance

🍂

Mulch Calculator

Mulch in cubic yards and bags.

Home

🔗

UTM Link Builder

Campaign tracking URLs.

Dev

⚡

Energy Converter

Joules, calories, kWh, BTU.

Converter

💪

Lean Body Mass Calculator

LBM by Boer, James, Hume.

Health

📈

CAGR Calculator

Compound annual growth rate.

Finance

🏷️

Meta Tag Generator

HTML, Open Graph, Twitter tags.

Dev

📆

Date Add / Subtract

Add or subtract time from a date.

Time

💳

Debt Payoff Calculator

Payoff time or monthly payment.

Finance

🎯

Probability Calculator

Single and combined event odds.

Math

🧒

Child Height Predictor

Predicted adult height.

Health

⛽

Fuel Economy Converter

MPG, L/100km, km/L.

Converter

🧱

Brick Calculator

Bricks needed for a wall.

Home

📈

Linear Interpolation

Interpolate between two points.

Math

🌐

HTTP Status Codes

What every code means.

Dev

📏

Inch Fraction Converter

Decimal inches, fractions, mm.

Converter

🌱

Sod Calculator

Sod pieces and pallets for a lawn.

Home

🎅

Secret Santa Generator

Draw gift-exchange pairs.

Everyday

🏊

Pool Volume Calculator

Gallons or liters your pool holds.

Home

📡

Wavelength Calculator

Wavelength, frequency, wave speed.

Math

📈

Pay Raise Calculator

New pay and raise percentage.

Finance

🕓

Military Time Converter

12-hour ↔ 24-hour, with chart.

Time

💪

FFMI Calculator

Fat-Free Mass Index.

Health

🧲

Force Calculator

Solve F = m × a.

Math

🏦

Down Payment Calculator

Down payment, percent and loan.

Finance

⚡

Power Converter

Watts, kW, horsepower, BTU/h.

Converter

🪚

Wall Framing Calculator

Studs and plates for a wall.

Home

👥

Random Team Generator

Split names into fair teams.

Everyday

🚀

Kinetic Energy Calculator

Solve KE = ½mv².

Math

📈

Future Value Calculator

Project investment growth.

Finance

🪵

Firewood Cord Calculator

Cords and face cords in a stack.

Home

🔧

Torque Converter

Nm, ft-lb, in-lb, kgf-m.

Converter

🗓️

Day of the Week Calculator

Weekday for any date.

Time

🔢

Rounding Calculator

Round by decimals, nearest, or mode.

Math

🧍

Body Surface Area

BSA by Mosteller, DuBois & more.

Health

🏗️

Rebar Calculator

Rebar grid and length for a slab.

Home

📶

Data Transfer Converter

Mbps, MB/s, Gbps and more.

Dev

🔡

ASCII Table

Codes, hex, binary, characters.

Dev

🔢

Arithmetic Sequence

Nth term and sum of a sequence.

Math

🏦

APY Calculator

Rate + compounding to APY.

Finance

🏠

Roof Area Calculator

Roof area, squares and bundles.

Home

📻

Frequency Converter

Hz, kHz, MHz, GHz, RPM.

Converter

📑

MIME Types

Content-Type for any extension.

Dev

🔢

Geometric Sequence

Nth term, sum and infinite sum.

Math

🛟

Emergency Fund Calculator

How much to set aside.

Finance

🚜

Excavation Calculator

Dirt volume, swell and loads.

Home

🧲

Force Converter

Newtons, lbf, kgf, dyne.

Converter

📋

Markdown Table Generator

Build and copy Markdown tables.

Dev

📐

Pythagorean Theorem

Solve a² + b² = c².

Math

🚗

Car Lease Calculator

Monthly lease payment estimate.

Finance

🧯

Insulation Calculator

Batts or blown-in by area & R-value.

Home

🚰

Flow Rate Converter

GPM, L/min, m³/h, CFM.

Converter

📨

HTTP Headers Reference

Common request & response headers.

Dev

📐

Distance Formula Calculator

Distance between two points.

Math

⏳

Rule of 72 Calculator

Years to double your money.

Finance

🧱

Paver Calculator

Pavers needed for a patio.

Home

⏱️

Time Calculator

Add & subtract time durations.

Time

⌨️

HTML Symbols & Entities

Entity codes to copy.

Dev

🖼️

Image Compressor

Compress, resize & convert — no upload.

Everyday

🔢

MD5 Hash Generator

MD5 of any text or file.

Dev

✅

File Checksum

Verify SHA-256, MD5, CRC32 — no upload.

Dev

🔐

Text Encryption (AES-256)

Password-encrypt text, client-side.

Dev

🔏

HMAC Generator

Compute & verify HMAC signatures.

Dev

🗝️

Cipher Decoder

Caesar, ROT13, Vigenère & Atbash.

Everyday

＠

Username Generator

Cool, aesthetic & gamer handles.

Everyday

🏷️

Business Name Generator

Brandable company name ideas.

Everyday

✉️

Email Signature Generator

HTML signature for Gmail & Outlook.

Everyday

🗄️

Test Data Generator

Fake mock data as CSV or JSON.

Dev

🔁

Recurring Date Generator

List repeating dates & schedules.

Time