Free Online Calculators
Finance, math, health, construction, and everyday tools in one searchable catalog.
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Paver Calculator — Patio Layout, Base & Packs
Plan a patio or path: compare straight paver layouts, count cuts and estimate base, bedding, packs and supplier costs.
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Picture Frame Calculator — Dimensions & Cut List
Plan a rabbeted picture frame from its package, outside or visible opening. Get finished rail dimensions, a feasible stock cutting plan and a printable shop sheet.
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Pipe Displacement Calculator
Compare closed-end, open-end and steel-body pipe displacement from actual OD, ID and length; solve target displacement length and cross-check internal capacity.
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Plant Spacing Calculator — Bed Layout & Plant Count
Plan actual planting places in a rectangular bed, compare row directions and turn the layout into a whole-pack plant order.
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Pool Salt Calculator
Work out how much pool salt to weigh, how many bags to buy and what remains. Preview salt levels and compare high-salt readings.
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Pregnancy Due Date Calculator — Weeks, IVF & Timeline
Estimate your due date and gestational age from last period, conception, IVF transfer, ultrasound age, or a known clinical due date, with a week-by-week visual timeline.
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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.
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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.
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Rafter Length Calculator — Pitch, Overhang & Ridge
Calculate common rafter line length with roof pitch, horizontal overhang and ridge-board deduction. View the section and print your measurements.
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Random Number Generator — One Number or a Unique Sample
Generate one number from a clearly labelled inclusive range, or create, sort, copy and download a larger random sample.
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Rectangular Tube Load Calculator — RHS & SHS Beam
Check RHS or SHS bending stress, deflection and estimated load capacity for steel, stainless steel or aluminum with simple, fixed or cantilever supports.
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Retaining Wall Calculator — Blocks, Gravel, Drainage & Cost
Estimate a segmental retaining wall from editable block geometry. Calculate courses, blocks, pallets, caps, base and drainage aggregate, pipe, fabric, excavation and cost.
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