Free Online Calculators
Finance, math, health, construction, and everyday tools in one searchable catalog.
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Drywall Mud Calculator — Compound & Tape Purchase Plan
Duct Size Calculator — Compare Available Sizes
Eigenvalue & Eigenvector Calculator
Fabric Yardage & Cut Layout Calculator
Fence Calculator — Panels, Posts, Gates & Cost
Fence Picket Calculator — Boards, Gaps & Layout
Firewood Cord Calculator — Stack & Delivery Check
Free Date Calculator — Days Between Dates & Age Calculator
French Drain Calculator — Gravel, Pipe & Fabric
GCF and LCM Calculator
Generator Sizing Calculator — Running & Starting Watts
Granny Square Blanket Calculator
Calculator descriptions
Drywall Mud Calculator — Compound & Tape Purchase Plan
Estimate joint compound and paper tape from installed drywall area, then round to whole containers and subtract full packages already on hand.
Duct Size Calculator — Compare Available Sizes
Compare your round and rectangular duct sizes against airflow, velocity, straight friction and available space. Work in US or SI units and save your comparison.
Eigenvalue & Eigenvector Calculator
Find eigenvalues, full real or complex eigenvector bases and multiplicities. Explore the transformation and check diagonalization over real and complex numbers.
Fabric Yardage & Cut Layout Calculator
Lay out rectangular fabric pieces with grain controls. Calculate yardage to buy, check an existing cut and print your cutting worksheet.
Fence Calculator — Panels, Posts, Gates & Cost
Plan fence panels, shared posts and gate openings for connected or separate runs. Compare material, delivery and installation quotes.
Fence Picket Calculator — Boards, Gaps & Layout
Plan individual fence pickets across unequal bays. See even gaps, inspect board positions, add whole spare boards and print your layout.
Firewood Cord Calculator — Stack & Delivery Check
Measure one or more compact firewood stacks, compare them with a full cord and check the quantity on a receipt.
Free Date Calculator — Days Between Dates & Age Calculator
Calculate days between dates, add or subtract days, or find an exact age with weekend controls, clear steps, and instant visual results.
French Drain Calculator — Gravel, Pipe & Fabric
Plan a French drain with changing ground levels. Estimate gravel, pipe pieces, fabric rolls and your material costs with a live trench profile.
GCF and LCM Calculator
Find the greatest common factor and least common multiple of several whole numbers. Explore equal chunks and repeating cycles with exact counts and steps.
Generator Sizing Calculator — Running & Starting Watts
Size a generator from your appliance nameplate watts. Compare steady load, controlled motor starts and overlapping starts against both generator ratings.
Granny Square Blanket Calculator
Plan a blanket from measured motifs, edit its assembly map and calculate colour-specific yarn and whole balls after partial stock.
