Free Online Calculators
Finance, math, health, construction, and everyday tools in one searchable catalog.
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Retirement Calculator — Savings & Monthly Income
Estimate savings at retirement from your age, current balance, and monthly contribution. Then refine income, spending, returns, and inflation.
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Roof Shingle Calculator — Roof Planes, Bundles & Cost
Plan shingle bundles for multiple roof planes, with pitch, product coverage, starter strips, ridge caps and your material quotes.
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Running Pace Calculator — Time, Distance & Splits
Calculate running pace, finish time, or distance with only the two values you know, then optionally build exact even or negative splits.
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Salary Calculator — Hourly to Annual Pay
Convert hourly, daily, weekly, monthly, or annual gross pay instantly. Optionally adjust schedule, unpaid time, overtime, bonus, and raise.
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Sleep Calculator — Bedtime, Wake Time & Duration
Plan bedtime from a required wake time, find a wake time from bedtime, or measure an overnight sleep window. Compare the result with CDC age guidance and optionally explore variable cycle scenarios.
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Sod Calculator — Rolls, Pallets & Installation Cost
Plan lawn areas, whole pallets or loose rolls, and compare your quoted costs with refundable pallet deposits shown separately.
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Soil Calculator — Topsoil, Raised Beds, Bags & Cost
Plan new soil for beds and measured areas. Subtract existing fill and compare whole bags with bulk orders and delivery quotes.
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Solar & Battery Calculator: Output, Backup and Payback
Estimate rooftop solar panels, output, self-use, exports, battery size, backup hours, shifted energy, payback and 20-year cash flow.
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Stair Stringer Calculator — Rise, Run & Layout
Plan a straight staircase, fit the available space and compare riser counts. See a proportional drawing and print your dimensions in inches or millimetres.
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Steel Tube Roof Truss Calculator — Loads & Deflection
Build a gable, mono-pitch or arched rectangular-tube truss and calculate roof loads, reactions, member forces, deflection, tube mass and a cut schedule.
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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.
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Tip Calculator — Tax, Split Bill & Custom Shares
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.
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