Other Calculators
Everyday helpers for dates, ages, grades, and school — tuned to US conventions.
Age Calculator
Find your exact age in years, months, and days, plus a countdown to your next birthday.
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Date Calculator
Free date calculator: add or subtract years, months, weeks, and days from any date, or count the days and business days between two dates.
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GPA Calculator
Calculate your grade point average on the standard US 4.
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Time Calculator
Add or subtract hh:mm:ss durations with totals in every unit.
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Hours Calculator
Hours and minutes between start and end times, minus breaks, with decimal hours.
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Grade Calculator
Compute your weighted course grade and the score needed on the final to hit your target.
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Height Calculator
Convert heights between centimeters and feet/inches, plus mid-parental child height estimates.
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Concrete Calculator
Slab and footing concrete volume in cubic yards with 80/60/40-lb bag counts.
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IP Subnet Calculator
Network address, broadcast, host range, wildcard mask, class, and usable hosts from any IPv4/CIDR.
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Bra Size Calculator
US bra size from band and bust measurements, with sister-size suggestions.
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Password Generator
Cryptographically random passwords with charset control, ambiguity exclusion, and entropy readout.
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Dice Roller
Roll up to twelve dice of any type with modifiers and per-die results.
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Fuel Cost Calculator
Trip fuel cost from distance, MPG, and gas price, split across passengers.
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Voltage Drop Calculator
Voltage drop by wire gauge, length, material, and phase with NEC percentage verdict.
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BTU Calculator
Air-conditioner BTU sizing from room area, insulation, sun exposure, occupancy, and ceiling height.
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Square Footage Calculator
Area in square feet for rectangles, circles, triangles, and trapezoids with material pricing.
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Time Zone Calculator
Convert times across US and world time zones using the IANA database with DST correctness.
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Love Calculator
Deterministic just-for-fun compatibility score from two names.
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GDP Calculator
National GDP via the expenditure identity with nominal vs real deflator adjustment.
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Gas Mileage Calculator
True MPG from odometer readings and gallons between fill-ups, with cost-per-mile.
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Horsepower Calculator
Convert torque and RPM into horsepower, with kW and PS equivalents.
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Engine Horsepower Calculator
Estimate crank/engine horsepower from drag-strip quarter-mile ET or trap speed and vehicle weight.
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Stair Calculator
Stair layout: riser count, actual rise, stringer length, angle, and IRC comfort-rule checks.
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Resistor Calculator
Decode 4-band resistor color codes to resistance and tolerance instantly.
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Ohms Law Calculator
Enter any two of voltage, current, resistance, and power — get the rest.
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Electricity Calculator
Appliance energy use and cost per day/month/year from wattage and usage hours.
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Shoe Size Conversion
Convert shoe sizes between US, UK, EU systems and foot length in cm, men's and women's.
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Tip Calculator
Restaurant tip calculator with bill splitting and common US tip percentages.
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Mileage Calculator
Distance-driven fuel use and per-person trip costs for carpooling.
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Density Calculator
Solve density, mass, or volume from the other two, with common unit presets.
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Mass Calculator
Convert weight/mass across metric and imperial units simultaneously.
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Weight Calculator
Surface gravity conversions: what you weigh on the Moon, Mars, Jupiter, and beyond.
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Speed Calculator
Solve speed, distance, or time, converting mph, km/h, m/s, and knots.
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Molarity Calculator
Solution molarity from mass, molecular weight, and volume — lab-prep ready.
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Molecular Weight Calculator
Molar mass from chemical formulas including parentheses and hydrates, with element breakdown.
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Roman Numeral Converter
Two-way converter between Arabic numbers and canonical Roman numerals (1–3999).
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Golf Handicap Calculator
World Handicap System index from recent rounds: differentials, best-8 averaging, and course handicap.
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Sleep Calculator
Wake refreshed: bedtime options counting 90-minute sleep cycles plus falling-asleep buffer.
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Tire Size Calculator
Compare two tire sizes: diameter, sidewall, revs/mile, and speedometer error percent.
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Roofing Calculator
Roof area from footprint and pitch: squares, shingle bundles, and material cost.
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Tile Calculator
Tile count for floors and walls including waste factor and box coverage.
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Mulch Calculator
Landscape mulch volume by bed area and depth, in cubic yards and 2-cu-ft bags.
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Gravel Calculator
Crushed stone volume and tonnage from area, depth, and material density.
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Wind Chill Calculator
Feels-like temperature using the official National Weather Service wind chill formula.
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Heat Index Calculator
How hot it really feels: heat index from temperature and humidity with NWS adjustments.
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Dew Point Calculator
Condensation temperature from air temperature and humidity via Magnus-Tetens.
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Bandwidth Calculator
Monthly hosting bandwidth from traffic patterns plus file download-time estimates.
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Base64 Encode / Decode
UTF-8-safe Base64 encoding and decoding directly in your browser.
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URL Encode / Decode
Percent-encode URLs and query parameters, or decode them back, fully client-side.
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Time Duration Calculator
Exact duration between start and end clock times, optionally excluding unpaid breaks.
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Day Counter
Count total days, weeks, and Monday–Friday business days between two dates.
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Day of the Week Calculator
Weekday for any historical or future date, plus ISO week number and day of year.
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Time Card Calculator
Weekly timesheet with in/out times and breaks; totals hours and overtime pay at 1.
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Conversion Calculator
Universal unit converter across ten measurement categories including temperature.
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About these calculators
The odds and ends that come up constantly: How old exactly am I? When is 90 days from today? What does a B+ average across these credits give me? Each tool is tuned to US conventions — federal weekday calendars, month-end date clamping, and the standard 4.0 grading scale.
Everything runs instantly in your browser with zero data collection.