Free Online Calculators
Finance, math, health, construction, and everyday tools in one searchable catalog.
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Alcohol Dilution Calculator — Water or Alcohol to Add
Square Feet Calculator — Rooms & Floor Plans
Water Volume Calculator — Area, Depth & Gallons
Grade Calculator — Weighted Grades, Final Exam & GPA
Age Calculator
Aquarium Volume Calculator — Water Level, Substrate & Sump
Arrow Kinetic Energy Calculator — Momentum & Measurement Journal
Battery Runtime Calculator — Backup Load Planner
Box Cushion Calculator & Mixed Fabric Plan
Candle Wax Calculator
Circle Skirt Calculator — Pattern & Fabric
Continuous Bias Binding Calculator
Calculator descriptions
Alcohol Dilution Calculator — Water or Alcohol to Add
Calculate water or stronger alcohol to add, prepare an exact final volume, lower or raise ABV, blend two strengths, and convert U.S. proof.
Square Feet Calculator — Rooms & Floor Plans
Calculate square feet for one room or a full floor plan in exact feet and inches. Add rooms by floor, subtract excluded areas, and estimate materials and cost.
Water Volume Calculator — Area, Depth & Gallons
Calculate US gallons from square feet and water depth, then plan pools, ponds, tanks, materials and volume conversions with editable examples.
Grade Calculator — Weighted Grades, Final Exam & GPA
Calculate weighted course grades, final exam targets, semester and cumulative GPA, or the GPA needed to reach a goal.
Age Calculator
Calculate exact calendar age in years, months and days, total elapsed days, hours and minutes, age on any date, and the next birthday.
Aquarium Volume Calculator — Water Level, Substrate & Sump
Measure tank water in six shapes, account for substrate and decor, add operating sump water, and compare your estimate with a measured fill.
Arrow Kinetic Energy Calculator — Momentum & Measurement Journal
Calculate arrow kinetic energy and momentum from finished arrow mass and speed. Keep repeated measurements and compare separate setups in a transparent journal.
Battery Runtime Calculator — Backup Load Planner
Plan how long a battery can power your outage loads. Switch appliances on or off, enter measured watts and duty cycles, and check the battery, goal and inverter together.
Box Cushion Calculator & Mixed Fabric Plan
Plan finished box cushion covers of different sizes on one fabric. Get cut pieces, zipper halves, a layout and an existing-cut check.
Candle Wax Calculator
Plan mixed candle sizes, weigh wax and fragrance, and work out complete batches from your ingredient stock.
Circle Skirt Calculator — Pattern & Fabric
Draft quarter to double-circle skirts with seam allowances, a waistband and fabric layout. Print an actual-size panel on A4 or Letter paper.
Continuous Bias Binding Calculator
Plan continuous bias tape from a fabric square. See full-width bands, discarded fabric and the square needed for your required length.
