Free Online Calculators
Finance, math, health, construction, and everyday tools in one searchable catalog.
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Water intake calculator — daily hydration range
Estimate a practical daily drinking range from weight, exercise and heat, with glasses, hourly pace and transparent adjustments.
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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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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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Ovulation Calculator — Fertile Window & Cycle Calendar
Estimate ovulation, fertile-window and next-period dates from an average cycle or a variable cycle-length range, with a visual calendar and three-cycle forecast.
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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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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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Mortgage Calculator — Payment, Affordability & Extra Savings
Estimate monthly mortgage costs, cash to close, amortization, and extra-payment savings, or plan an affordable home price from income, debts, and target DTI.
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Adult BMI Calculator — BMI, Healthy Weight & Chart
Calculate adult BMI in metric or US units. See the CDC category, healthy weight range for your height, distance to the range, formula, and a visual BMI chart.
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Car Loan Calculator — Payment, Budget, Payoff & Offers
Calculate a car payment from the complete deal, reverse a monthly budget, test extra-payment payoff, compare two offers, or estimate a lease.
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Loan Calculator - Payments, Payoff & Amortization
Calculate a fixed loan payment, model extra-payment payoff, estimate an affordable loan amount, compare offers, and inspect annual or monthly amortization.
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VAT Calculator — Add, Remove & Find VAT
Add VAT to a net price, remove VAT from a gross total, or find the effective VAT rate with currencies, rounding, formulas, and a clear tax breakdown.
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Area Calculator — Square Feet, Shapes, Rooms & Land
Calculate square footage for shapes, rooms, walls, roofs, and irregular land; include cutouts, waste, packages, cost, formulas, and diagrams.
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Wallpaper Calculator — Rolls, Pattern Repeat & Cost
Estimate wallpaper rolls for rooms or separate walls. Account for strip rounding, trim, straight or half-drop repeat, reserve, reusable offcuts, leftover length, and cost.
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Brick & Block Calculator — Wall, Mortar, Pallets & Cost
Estimate brick or concrete block walls with doors and windows. Calculate courses, units, waste, pallets, mortar bags, edge cuts, and material cost.
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Tile Calculator — Square Feet, Boxes & Layout
Enter the surface and tile size to see how many tiles and boxes you need. Optionally refine waste, layout, grout, and material cost.
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Paint Calculator — Gallons, Liters, Cans & Cost
Estimate paint for rooms, walls, and ceilings. Subtract doors and windows, set coats and coverage, and see gallons or liters, cans, leftover paint, and cost.
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Alcohol Dilution Calculator — Blend ABV & Convert Proof
Dilute alcohol with water, blend two strengths, plan a target batch, or convert ABV and U.S. proof with formulas, tables, and a visual mixture breakdown.
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Quadratic Equation Calculator — Roots, Steps & Graph
Solve quadratic equations in standard or vertex form, or build one from roots. See real or complex roots, discriminant, vertex, steps, forms, points, and a graph.
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