Free Online Calculators
Finance, math, health, construction, and everyday tools in one searchable catalog.
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Quilt Backing Calculator — Yardage & Panel Layout
Quilt Binding Calculator — Strips & Fabric Yardage
RC Time Constant Calculator — Charge, Discharge & Tolerances
Screen Size Calculator
Serial Dilution Calculator — Transfer & Retained Volumes
Soap & Lye Calculator — Build and Resize Your Recipe
Spring Rate Calculator — Geometry & Measured Loads
Time Calculator — Hours, Duration & Timesheet
Tip Calculator
Titration Calculator — Concentration, Volume & Repeated Trials
Yarn Calculator
pH Calculator
Calculator descriptions
Quilt Backing Calculator — Yardage & Panel Layout
Compare horizontal and vertical backing layouts, seam placement and fabric yardage. Get a proportional diagram, cutting list and printable plan.
Quilt Binding Calculator — Strips & Fabric Yardage
Plan straight-grain binding strips, account for joins and end allowance, and buy the right fabric increment. Includes a visual cutting plan and printable list.
RC Time Constant Calculator — Charge, Discharge & Tolerances
Explore capacitor charge and discharge, time to a voltage threshold, and timing ranges from resistor and capacitor tolerances.
Screen Size Calculator
Find screen width and height from its diagonal, compare two screens at the same scale and see how much space a movie or image actually uses.
Serial Dilution Calculator — Transfer & Retained Volumes
Plan a dilution series with enough liquid left in every tube. Compare prepared and retained volumes, edit concentrations and save your transfer plan.
Soap & Lye Calculator — Build and Resize Your Recipe
Build a soap recipe with multiple oils, adjust SAP and lye purity, resize your batch and save a complete recipe file.
Spring Rate Calculator — Geometry & Measured Loads
Estimate a compression spring rate from round-wire geometry, or measure rate between two force and loaded-length readings. Compare the model and its provenance.
Time Calculator — Hours, Duration & Timesheet
Add or subtract time, find hours between clocks, total timesheet shifts and pay, or convert duration units with clear visual results.
Tip Calculator
Calculate restaurant tips before or after tax, split the bill equally or by custom shares, round the total, and see exactly what each person pays.
Titration Calculator — Concentration, Volume & Repeated Trials
Solve titration concentration or volume from a balanced reaction. Analyse repeated direct titrations with blank correction, dilution and a transparent report.
Yarn Calculator
Estimate blanket yarn from a weighed swatch, preview repeating stripes, subtract partial balls and print a colour-by-colour shopping list.
pH Calculator
Calculate ideal equilibrium pH for strong or weak acids and bases or conjugate buffers. Explore dilution with a curve that includes the contribution of water.
