Other Calculators
Everyday calculators: dates and time, GPA, home improvement (concrete, tile, roofing), developer utilities (UUID, timestamp, JSON, base64), vehicle (MPG, HP), and modern life tools (EV charging, solar ROI, sleep cycles).
Date and time tools include age, day counter, day-of-week, time duration, and time-card calculators.
Home-improvement quantity calculators cover concrete, gravel, mulch, tile, roofing, and square footage — essential before a trip to the hardware store.
Developer tools include UUID, Unix timestamp, Base64, URL encoding, JSON prettifier, and an LLM token-cost calculator for Claude, GPT, and Gemini APIs.
All other calculators
Age Calculator
Age in years, months and days.
Date Calculator
Add or subtract days from a date.
Time Calculator
Add and subtract times.
Hours Calculator
Hours between two times.
GPA Calculator
Grade point average across courses.
Grade Calculator
Final grade from weighted components.
Height Calculator
Convert between height units.
Concrete Calculator
Volume of concrete for slabs and footings.
IP Subnet Calculator
IPv4 subnet math and ranges.
Bra Size Calculator
Bra size from band and bust.
Password Generator
Strong random passwords.
Dice Roller
Roll any number of dice.
Conversion Calculator
Length, mass, volume, temperature and more.
Unit Converter
Convert between length, mass, volume, temperature and speed units.
Fuel Cost Calculator
Cost of a trip by fuel efficiency.
Voltage Drop Calculator
Voltage drop across wire length.
BTU Calculator
HVAC sizing for a room.
Square Footage Calculator
Square footage of rooms.
Time Card Calculator
Weekly timesheet.
Time Zone Calculator
Convert times across zones.
Love Calculator
For fun: compatibility score.
GDP Calculator
GDP from C + I + G + NX.
Gas Mileage Calculator
MPG from distance and fuel.
Horsepower Calculator
HP from torque and RPM.
Engine Horsepower Calculator
HP from 1/4-mile or 0–60.
Stair Calculator
Stair rise, run and stringer.
Resistor Calculator
Color code to resistance.
Ohms Law Calculator
V = I × R.
Electricity Calculator
Electricity cost of appliances.
Shoe Size Conversion
US / EU / UK / JP sizes.
Tip Calculator
Tip amount and split.
Mileage Calculator
Trip mileage cost.
Density Calculator
ρ = m / V.
Mass Calculator
Mass from density and volume.
Weight Calculator
Weight on other planets.
Speed Calculator
Speed, distance, time.
Molarity Calculator
Solution molarity.
Molecular Weight Calculator
Molar mass from a simple formula.
Roman Numeral Converter
Convert to / from Roman numerals.
Golf Handicap Calculator
Handicap index from recent rounds.
Sleep Calculator
Ideal wake / bedtimes for full cycles.
Tire Size Calculator
Compare tire specs.
Roofing Calculator
Roofing squares and materials.
Tile Calculator
Tiles needed for an area.
Mulch Calculator
Cubic yards of mulch.
Gravel Calculator
Gravel quantity and weight.
Wind Chill Calculator
Apparent temperature with wind.
Heat Index Calculator
Apparent temperature with humidity.
Dew Point Calculator
Dew point from temp and RH.
Bandwidth Calculator
Time to transfer a file.
Base64 Encode / Decode
Encode or decode Base64.
URL Encode / Decode
Encode or decode URL strings.
Time Duration Calculator
Duration between two date-times.
Day Counter
Days between two dates.
Day of the Week Calculator
Day of week for any date.
LLM Token Cost Calculator
API cost for Claude, GPT, and other LLMs.
Unix Timestamp Converter
Epoch ↔ human-readable date.
Color Contrast (WCAG) Calculator
Contrast ratio and WCAG AA/AAA pass.
Word & Character Counter
Words, characters, reading time.
UUID Generator
Generate version-4 UUIDs.
JSON Prettifier & Minifier
Format JSON or minify to one line.
Recipe Scaler
Scale ingredients up or down by servings.
Cooking Unit Converter
Convert cups, tbsp, ml, and grams for common baking ingredients.
JWT Decoder
Inspect a JSON Web Token's header and payload, with time-claim decoding.
EV Charging Cost Calculator
Home or public EV charging cost and time.
Solar Panel ROI Calculator
Payback period of a residential solar system.
Cost of Living Comparison
Income equivalent between cities.