Calculate. Understand. Decide.

01Tip calculatorTip, total, and split the bill.→ 02Discount calculatorSale price and stacked discounts.→ 03VAT calculatorAdd or remove tax from a price.→

01Margin calculatorGross margin, markup, target selling price.→ 02Break-even calculatorUnits and revenue to cover fixed cost.→ 03ROI calculatorReturn on investment and annualized rate.→ 043D Printer Buy vs Outsource CalculatorCompare the real cost of owning a 3D printer with outsourcing production.→

01Compound interest calculatorSavings and investment growth with contributions.→

0112 Hour Shift CalculatorCalculate shift pay, overtime and weekly or annual earnings.→

0110/1 ARM CalculatorEstimate payments before and after a 10/1 adjustable-rate reset.→ 02How Much House Can I Afford?Estimate an affordable home price from income, debt and housing costs.→

01529 CalculatorEstimate future college costs, savings growth and funding coverage.→ 0250/30/20 Rule CalculatorPlan needs, wants and savings from your after-tax income.→ 03Savings goal calculatorContribution needed for a target.→ 0470/20/10 Rule Money CalculatorFree 70/20/10 rule money calculator to split after-tax income into essentials, savings or debt, and lifestyle spending with live charts, formulas, examples and practical guidance.→ 05Accounting Profit CalculatorFree accounting profit calculator to calculate revenue, explicit costs, accounting profit and profit margin with live charts, formulas, worked examples and educational explanations.→ 06AfterFree after-tax cost of debt calculator. Calculate the effective borrowing cost after the interest tax shield, annual interest, tax savings and sensitivity to tax rates.→ 07FinanceCompound growth, loans, inflation, and savings targets with year-by-year tables.→

01Loan calculatorMonthly payment and amortization.→

01401(k) CalculatorRetirement savings, employer match and long-term growth.→ 02403(b) CalculatorEstimate retirement savings, employer contributions and growth.→

01Inflation calculatorPurchasing power over time.→

013X Rent CalculatorCalculate required gross income, maximum rent and rent-to-income ratio using a 3X rent guideline.→

01BMI calculatorBody mass index and healthy weight range.→ 02Ideal weight calculatorDevine, Robinson, Miller, Hamwi.→ 03Body fat calculatorUS Navy circumference method.→

01Calorie calculatorBMR and TDEE from Mifflin-St Jeor.→

01Heart rate zone calculatorTraining zones from age and resting pulse.→ 02HealthBMI, calories, ideal weight, body fat, and training zones. Not medical advice.→

01Percentage calculatorPercent of, change, and difference.→

01Quadratic equation calculatorax² + bx + c = 0, discriminant, vertex.→

01Ratio calculatorEquivalent ratios, simplify, split.→ 02Average calculatorMean, median, mode, range.→ 03GCF & LCM calculatorGreatest common factor and least common multiple.→ 04Scientific notation calculatora × 10^n and engineering notation.→ 05Rounding calculatorDecimals, sig figs, half-up and half-even.→ 06Significant figures calculatorCount and round to n sig figs.→ 07Modulo calculatora mod n remainder and quotient.→ 08Standard deviation calculatorSample s, population σ, variance, mean.→ 09Z-score calculatorz = (x − μ) / σ and tail areas.→ 10Combination & permutation calculatornCr, nPr, with and without repetition.→

01Circle calculatorRadius, circumference, area, arc, sector.→ 02Ellipse calculatorArea, Ramanujan circumference, eccentricity.→ 03Regular polygon calculatorn-gon area, perimeter, apothem, interior angle.→ 04Trapezoid calculatorArea, midsegment, isosceles leg.→ 05Parallelogram calculatorArea from sides and angle, or base and height.→ 06Rhombus calculatorArea from diagonals or side and angle.→ 07Rectangle calculatorArea, perimeter, diagonal.→ 08Square calculatorSide, area, diagonal, inradius, circumradius.→ 09Kite calculatorDiagonals, sides, area.→ 10Annulus calculatorRing between two circles.→ 11Sector calculatorPizza slice — area, arc, chord, segment.→ 12Segment calculatorCap between chord and arc.→ 13Hexagon calculatorRegular hexagon from any one measure.→ 14Pentagon calculatorRegular pentagon and golden diagonal.→ 15Octagon calculatorRegular octagon and three diagonals.→ 16Dodecagon calculator12-gon — five diagonal lengths.→

01Triangle calculatorSSS, SAS, right triangle — sides, angles, area.→ 02Pythagorean theorem calculatora² + b² = c² from any two sides.→ 03Law of cosines calculatorc² = a²+b²−2ab cos C.→ 04Law of sines calculatora/sin A = 2R.→ 05Heron formula calculatorArea from three sides.→

01Sphere calculatorRadius, surface, volume — and π form.→ 02Cylinder calculatorVolume, lateral and total surface.→ 03Cone calculatorVolume, slant, lateral and total surface.→ 04Pyramid calculatorSquare or rectangular — volume and surface.→ 05Rectangular prism calculatorBox volume, surface, space diagonal.→ 06Cube calculatorVolume, surface, both diagonals.→ 07Frustum calculatorTruncated cone — volume and surfaces.→ 08Torus calculatorDonut volume and surface.→ 09Tetrahedron calculatorRegular tetrahedron — volume a³/(6√2).→ 10Octahedron calculatorEight triangles — dual of the cube.→ 11Dodecahedron calculatorTwelve pentagons — dual of the icosahedron.→ 12Icosahedron calculatorTwenty triangles — D20.→

01Exponent & root calculatorPowers, square root, cube root, nth root.→ 02Logarithm calculatorlog base b, log10, ln, antilog.→

01Fraction calculatorAdd, subtract, multiply, divide fractions.→

01Absence Percentage CalculatorCalculate employee absence percentage and absenteeism rate from employees, workdays, and days absent. Explore formulas, examples, live charts, tables, and practical interpretation.→ 02Accrual Ratio CalculatorFree accrual ratio calculator for balance sheet and cash flow accrual ratios, with live charts, formulas, worked examples and an educational guide to earnings quality.→ 03ADR CalculatorFree ADR calculator for hotels and vacation rentals. Calculate Average Daily Rate from room revenue and rooms sold, with occupancy, RevPAR, live charts, formulas, examples and educational guidance.→ 04GeometryPlane figures and solids. One known length fills the rest; diagrams stay on the page.→ 05MathPercentages, algebra, and statistics — each tool shows the formula next to the result.→

01About ST CalculatorHow ST Calculator works: local browser calculations, transparent formulas, and no data collection. Built for clear financial decisions.→ 02Accumulated Depreciation CalculatorFree accumulated depreciation calculator with straight-line, declining-balance, sum-of-years→ 03Actual Cash Value CalculatorFree actual cash value calculator. Estimate ACV from today’s replacement cost, useful life, age, depreciation and deductible with live charts, schedule, formulas and educational guidance.→ 04Additional Funds Needed (AFN) CalculatorFree Additional Funds Needed (AFN) calculator to estimate the external financing required to support sales growth, with live charts, formulas, examples, tables and educational explanations.→ 05Adjusted Gross Income (AGI) CalculatorFree Adjusted Gross Income (AGI) calculator. Estimate AGI from income and eligible adjustments with live charts, formulas, examples, tables and educational explanations.→ 06AFFO CalculatorFree AFFO calculator for REIT analysis. Calculate FFO, adjusted funds from operations (AFFO), AFFO per share, live charts, formulas, worked examples and practical interpretation.→ 07BusinessMargin, break-even, and return on investment.→ 08ContactContact ST Calculator. Send us a message, question, suggestion, or business inquiry.→ 09Cookie PolicyCookie Policy for ST Calculator.→ 10FeedbackOnline calculator with clear inputs, formulas and results.→ 11Privacy PolicyPrivacy Policy for ST Calculator.→ 12Terms of UseTerms of Use for ST Calculator, covering calculator use, accuracy, limitations, intellectual property, links, and user responsibilities.→