Fast, Free Trade & Industrial Calculators
Every result updates as you type — roll and reel, tank and cylinder, chemistry, and trade math, all free and instant.
Popular calculators
Roll Length Calculator
Convert outer diameter, core diameter, and thickness into unwound length and turn count.
OD, ID, thickness → length, turns
Tank Volume Calculator
Calculate liquid volume in cylindrical, rectangular, or capped tanks from dimensions and fill height.
Tank shape, dimensions → volume, fill %
Solution Dilution Calculator
Calculate the dilution needed to hit a target concentration using C₁V₁ = C₂V₂.
Stock conc, target conc → diluent volume
Electricity Cost Calculator
Estimate the running cost of an appliance from wattage, hours of use, and your electricity rate.
Watts, hours/day, rate → daily/monthly cost
Roll & reel calculators
Wound-roll geometry for paper, film, foil, textile, and wire — find remaining length or predict a finished roll's outer diameter.
Roll Length Calculator
Unwound length, turn count, and surface area from outer diameter, core diameter, and thickness.
OD, ID, thickness → length, turns, area
Roll Diameter Calculator
The outer diameter a roll will reach after winding a known length onto a core.
Core, thickness, length → outer diameter
Tank & cylinder calculators
On-site tank volume from a dimension or dip reading — including horizontal tanks with rounded heads, where fill % isn't a straight line.
Tank Volume Calculator
Liquid volume of cylindrical, rectangular, or capped tanks from dimensions and fill height.
Shape, dimensions, fill height → volume, fill %
Cylinder Volume Calculator
Solve for a cylinder's volume, radius, or height from any two known dimensions.
Any 2 of radius/height/volume → the third
Chemistry & dilution calculators
Solution dilution, serial dilution series, and density-to-concentration lookups for NaOH, HCl, sulfuric acid, and bleach.
Solution Dilution Calculator
The dilution needed to hit a target concentration using C₁V₁ = C₂V₂.
Stock conc & volume → diluent volume
NaOH Concentration Calculator
Sodium hydroxide solution strength (%w/w) from specific gravity, or the reverse.
Specific gravity or %NaOH → the other
Bleach Dilution Calculator
How much bleach and water to mix for a target available-chlorine (ppm) solution.
Bleach %, target ppm → bleach & water amounts
Geometry & trade math calculators
A trade math toolbox as much as a geometry one — electricity cost, weighted averages, speed/distance/time, equations, and ratios.
Electricity Cost Calculator
The running cost of an appliance from wattage, hours of use, and your electricity rate.
Watts, hours/day, rate → cost
Ratio & Proportion Calculator
Solve a ratio, or scale a recipe or mixture to a new batch size.
Known ratio + new value → missing value
Weighted Average Calculator
A weighted average from a list of values and their weights.
Values + weights → weighted average
Finance calculators
Loan and mortgage math for financing equipment or a home — coming soon.
Why trust these numbers
Instant, no waiting
Every calculator runs entirely in your browser. Results update the moment you finish typing — no submit button, no page reload.
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Formulas you can verify
Every formula is derived from first principles and cross-checked against standard references — see the Sources note on each page.