Everyday Life & Household 11 calculators
- Party Ice Quantity CalculatorLatent heat of fusion of ice, 144 Btu/lbIce for a party is three separate quantities, and the usual "one pound per person" rule collapses all of them into a number…
- Party Tables & Chairs CalculatorSeating capacity is a perimeter problem. A round table seats however many 24-inch slices fit around its circumference, and a…
- Pet Ownership Annual Cost CalculatorHousehold budgeting — expected-value reserve methodThis calculator separates the three numbers that decide whether you can afford a pet: the first year , which carries adoption…
- Picture Frame & Mat Size CalculatorTrade framing dimensions (32 × 40 in board)Framing runs on four dimensions and each one is derived from the last: the mat opening, the mat outer size (which is also the…
- Picture Hanging Height Calculator57-inch gallery centre-line conventionThe mistake almost everyone makes is hanging art at the height they want the nail , when what they actually care about is the…
- Pizza Party Quantity CalculatorThis calculator turns a guest list into a pizza order. Enter how many adults and children you are feeding, how hungry they are…
- Pizza Size Value Comparison CalculatorPizza is sold by diameter and eaten by area, and those two quantities do not scale together. Area goes as the square of the…
- Pool Heating Cost CalculatorSensible heat equation with a surface heat-loss coefficientHeating a pool is two separate bills. The first is the one-off energy to lift the whole body of water to your target…
- Postage Stamps Needed CalculatorUSPS Domestic Mail Manual / Notice 123Enter what your envelope weighs and measures and this calculator decides whether the USPS prices it as a letter or as a large…
- Printer Ink & Toner Cost Per Page CalculatorISO/IEC 19752, 19798 and 24711 page yield methodsCost per page is cartridge price divided by rated page yield, and it is the only honest way to compare printers — a $60…
- Puppy Adult Weight CalculatorSize-class growth-fraction methodWeigh your puppy, note its age in weeks, pick the size class it belongs to, and this calculator divides the weight by the…
Arithmetic, Algebra & Number Theory 9 calculators
- Percent Error CalculatorJCGM 100:2008 (GUM)Enter what you measured and what the value should have been, and this calculator returns the absolute error, the relative error…
- Percentage CalculatorBase-100 proportion identityEvery percentage question is one of three questions, and this calculator answers all three at once. Enter a percent and a whole…
- Percentage Change CalculatorRelative change on the earlier value as basePercent change measures how far a value has moved relative to where it started. Enter the earlier figure and the later figure…
- Percentage Difference CalculatorPercentage difference compares two numbers when neither one is the baseline. It divides the gap between them by their mean…
- Percentage Increase & Decrease CalculatorMultiplicative percentage adjustmentApplying a percentage is a multiplication, not an addition. To raise a value by 20% you multiply by 1.20; to cut it by 20% you…
- Permutation Calculator (nPr)Permutations, arrangements of a multisetA permutation counts ordered arrangements. Gold, silver and bronze from eight runners is a permutation; a three-person…
- Prime Factorization CalculatorFundamental theorem of arithmeticEvery whole number above 1 is a product of prime numbers, and that product is unique apart from the order of the factors. This…
- Prime Number Checker CalculatorDeterministic trial divisionEnter a whole number and this calculator says whether it is prime, and if not, names the smallest prime that divides it —…
- Proportion Solver CalculatorCross-multiplication property of equal ratiosA proportion says two ratios are equal: a/b = c/d . Give this calculator any three of the four terms, say which one is missing…
Plumbing, Piping & Hydraulics 6 calculators
- Pipe Slope & Fall CalculatorIPC 2021 Table 704.1Give this calculator a run length and any one expression of grade — inches per foot, percent, a 1-in-X ratio, or the total fall…
- Pipe Volume CalculatorRight-circular-cylinder volume; 231 in³ per US gallonEnter the inside diameter and length of a pipe run and this calculator returns how much liquid it holds — in US gallons…
- Pipe Water Velocity CalculatorCopper Development Association velocity guidanceGive this calculator a flow rate and an inside diameter and it returns the mean water velocity in feet per second and metres…
- Pipe Weight Calculator (Empty & Water Filled)ASME B36.10M / B36.19M dimensionsPipe weight decides three things on a job: what the hangers and the structure have to carry, what the crane or the crew has to…
- Pool Chlorine Dosage CalculatorCDC Model Aquatic Health CodeChlorine dosing is a mass balance, not a guess. To raise free chlorine by one part per million in one gallon of water you need…
- PSI to Feet of Head ConverterHydrostatic pressure, p = ρghPressure and head are the same physical quantity wearing different clothes, and every pump curve, well calculation and…
Agriculture, Livestock & Landscaping 5 calculators
- Pasture Grazing Days CalculatorUSDA-NRCS Conservation Practice Standard 528, Prescribed GrazingMove the herd too late and you graze the regrowth; move it too early and you leave forage that goes stemmy before you return…
- Pearson Square Feed Ration CalculatorPearson square two-ingredient blendingThe Pearson square blends two feeds to hit an exact nutrient target — usually crude protein, but the same arithmetic…
- Plant Population per Acre Calculator1/1,000-acre stand-count method (Cooperative Extension)This calculator answers two different questions with the same arithmetic. Before planting, it converts a row width and an…
- Pond Volume & Acre-Feet CalculatorAcre-foot volumetric methodAlmost every decision about a pond is priced per acre or per acre-foot: fish stocking rates and liming are per surface acre…
- PTO Horsepower & Torque CalculatorASABE S203 / ISO 500 PTO speeds; P = T·n ÷ 5,252Power, torque and shaft speed are three views of one thing, and on a tractor PTO the link between them is fixed: horsepower…
Biology, Genetics & Clinical Lab 5 calculators
- Pack Years CalculatorUSPSTF 2021 lung cancer screening recommendationA pack-year is the standard way clinicians quantify cumulative tobacco exposure: one pack-year is twenty cigarettes a day for…
- PCR Master Mix CalculatorC₁V₁ = C₂V₂ dilution arithmeticGive this calculator your reaction volume, how many reactions you are setting up, and the stock and final concentration of each…
- PPV & NPV CalculatorBayes' theorem; STARD 2015 reporting guidelinePositive predictive value answers the only question a patient actually asks: my test came back positive — what is the chance I…
- Primer Melting Temperature (Tm) CalculatorSantaLucia unified nearest-neighbour thermodynamics (1998)Paste a primer sequence and this calculator returns its melting temperature four ways: the nearest-neighbour thermodynamic…
- Punnett Square Probability CalculatorMendel's laws of segregation and independent assortmentType each parent's genotype the way you would write it on paper — Aa , AaBb , AaBbCc — and this calculator builds the whole…
Corporate Finance & Valuation 5 calculators
- P/E Ratio CalculatorEPS per ASC 260 / IAS 33The price-to-earnings ratio is the price of one share divided by the earnings attributable to one share: how many dollars you…
- Payback Period CalculatorPayback period (undiscounted capital recovery)The payback period is how long an investment takes to repay its own cost out of the cash it generates. Enter the outlay and the…
- PEG Ratio CalculatorPrice/earnings-to-growth (Lynch convention)The PEG ratio divides a company's price-to-earnings multiple by the growth rate the market expects from its earnings, so that a…
- Price-to-Book (P/B) Ratio CalculatorBook value per share from GAAP shareholders' equityPrice-to-book compares what the market will pay for a share against what the accounts say the share owns. It is the standard…
- Profitability Index (PI) CalculatorDiscounted cash flow (benefit-cost ratio)The profitability index tells you how much present value a project creates per dollar committed to it. Enter the up-front…
Statistics & Probability 5 calculators
- P-Value Calculator from a Test StatisticExact distribution tail areasYou have a test statistic and you need its p-value. Choose the distribution — standard normal, Student t , chi-square or F —…
- Pearson Correlation Coefficient (r) CalculatorPearson product-moment correlationPearson's r measures how tightly two variables track a straight line together, on a scale from −1 to +1. Paste your paired…
- Percentile CalculatorSample quantile definitions (Hyndman & Fan, 1996)Enter a data set and a percentile and this calculator returns the value at that point in the sorted data, together with the…
- Probability Calculator (Single & Two Events)Kolmogorov probability axioms and the addition ruleGive this calculator the probabilities of two events and how they relate, and it returns every derived probability at once: the…
- Process Capability Cp & Cpk CalculatorAIAG SPC reference manualCapability indices compare the width of your specification against the width of your process. Enter the specification limits…
Cooking, Baking & Brewing 4 calculators
- Pizza Dough Ball CalculatorBaker's percentage (flour = 100%)Pizza is scaled backwards from the finished product: you know how many pizzas you need and how heavy each dough ball has to be…
- Pizza Dough Thickness Factor CalculatorLehmann dough thickness factor (oz per in²)Dough balls do not scale with diameter, they scale with area — and area grows with the square of the diameter. A 16-inch…
- Prime Rib Cooking Time CalculatorUSDA FSIS safe minimum internal temperaturesThis calculator tells you three things a roasting chart cannot: how long a standing rib roast of your exact weight needs in…
- Priming Sugar CalculatorFermentation stoichiometry with temperature-corrected residual CO₂This calculator gives the weight of priming sugar that will carbonate your batch to a chosen CO 2 level in the bottle. It does…
Legal, Claims & Settlements 4 calculators
- Pain and Suffering Multiplier CalculatorMultiplier and per-diem valuation conventionsPersonal injury damages split into two halves. Economic damages — medical bills, lost wages, out-of-pocket costs — are…
- Personal Injury Settlement CalculatorRestatement (Second) of Torts §924This calculator builds a personal injury claim the way a demand letter does: documented economic losses first, then a…
- Prevailing Wage & Fringe Benefit CalculatorDavis-Bacon Act, 40 U.S.C. §3141 et seq.; 29 CFR Part 5A prevailing wage determination sets two numbers for each classification: a basic hourly rate and a fringe benefit rate. A…
- Probate Fees & Executor Compensation CalculatorCalifornia Probate Code sections 10800 and 10810 statutory scheduleIn a statutory-fee state, probate compensation is a formula rather than a bill: a tiered percentage of the gross probate…
Chemistry & Chemical Engineering 3 calculators
- Percent Composition CalculatorIUPAC standard atomic weights (abridged, 2021)This calculator breaks a chemical formula into the mass percent contributed by each element, so you can check a CHN elemental…
- Percent Yield CalculatorPercent yield = actual / theoretical × 100Percent yield compares what you actually isolated with the maximum the stoichiometry allowed. Enter the mass you weighed and…
- pH & pOH CalculatorIUPAC pH definition, Kw = 1.0e-14 at 25 degCEnter any one of pH, pOH, [H + ], [OH − ], or the concentration of a strong acid or strong base, and this calculator…
Construction, Carpentry & Concrete 3 calculators
- Paint Coverage CalculatorSpread-rate methodGive this calculator a room's dimensions, the number of coats and the spread rate printed on the can, and it returns the…
- Paver & Paver Base CalculatorICPI Tech Spec 2; ASTM C33 bedding sandThis calculator turns a patio or driveway footprint into a complete material list: how many pavers to order once cuts are…
- Plywood & OSB Sheet CalculatorIRC Table R602.3(1) fastening scheduleSheet goods are sold whole and used in pieces, so a sheet count is never just area divided by 32. This calculator adds your…
Electrical Trade & Electronics 3 calculators
- Parallel Resistance CalculatorKirchhoff's current lawEnter up to six resistor values and this calculator returns the equivalent resistance of the parallel combination, the current…
- PCB Trace Width CalculatorIPC-2221B, Generic Standard on Printed Board DesignA PCB trace is a resistor you did not intend to design, and its width is set by how much temperature rise you are willing to…
- Power Factor Correction Capacitor CalculatorNEC 2023 Article 460; IEEE 18 shunt capacitor standardEnter the real power of a load, its present power factor and the power factor you want, and this calculator returns the…
Industrial, Logistics & Plant Operations 3 calculators
- Pallet Pattern Calculator (Cases per Pallet & Cube Utilization)GMA 48 × 40 in pallet footprint; ISO 3676 unit load sizesGive this calculator your case dimensions, your pallet footprint and the maximum height a loaded pallet may reach, and it…
- Paper Basis Weight to GSM CalculatorUS basis weight system (basis sheet sizes)US paper weights are a trap: 20 lb bond and 50 lb text are the same sheet, and 80 lb cover is more than twice as heavy as 80 lb…
- Press Sheet Imposition CalculatorSheetfed offset and digital cut-sheet imposition practiceThis calculator answers the first question on every print estimate: how many finished pieces come off one press sheet, and…
Insurance & Risk Management 3 calculators
- Personal Property Coverage CalculatorSpecial limits of liability on the homeowners formTwo things go wrong with contents coverage, and they are unrelated. The first is the overall limit — usually set as a…
- Professional Liability (E&O) Limit CalculatorClaims-made professional liability policy formA professional liability limit is bought against the worst engagement on your books, not against your revenue. This calculator…
- Pure Premium & Rate CalculatorASOP No. 53, Estimating Future Costs for Prospective Property/Casualty Risk TransferAn insurance rate is built, not chosen. It starts with the pure premium — expected claim frequency multiplied by expected…
Real Estate & Property Investment 3 calculators
- PMI CalculatorHomeowners Protection Act of 1998 (12 U.S.C. §4901 et seq.)Private mortgage insurance protects the lender, not you, and you pay for it whenever a conventional loan starts above 80% of…
- Price Per Square Foot CalculatorANSI Z765-2021 (single-family square footage measurement)Price per square foot is a sale price divided by the property's gross living area. It is the fastest way to compare houses of…
- Prorated Rent CalculatorLease proration conventions (30-day, actual-days, annualized)When a tenant moves in or out part-way through a month, the rent for that month has to be split. This calculator does it three…
Tax, Payroll & Insurance 3 calculators
- Progressive Tax Bracket CalculatorIRC §1 graduated rate schedule (Rev. Proc. 2025-32)Enter your taxable income and this calculator walks it up the federal graduated rate schedule one bracket at a time, showing…
- Property Tax Mill Rate CalculatorAd valorem property tax; mill = $1 per $1,000 of taxable valueA property tax bill is three numbers you rarely see together: the assessor's opinion of value, the fraction of that value your…
- PTO Accrual CalculatorPaid time off is earned in small pieces, and the piece size depends on how your employer measures it. This calculator converts…
AI, LLM & Machine Learning Engineering 2 calculators
- Perplexity Calculator (From Cross-Entropy Loss)Shannon entropy (base-e nats, base-2 bits)This calculator converts between the three ways the same quantity gets reported: cross-entropy loss, perplexity, and bits per…
- Prompt Caching Savings CalculatorPrefix-cache token pricing modelCaching a long, unchanging prompt prefix is not free: the first request pays a premium to write the cache, and every hit after…
Accounting & Financial Statement Analysis 2 calculators
- Piotroski F-Score CalculatorPiotroski (2000) F-Score, 9 signalsThe Piotroski F-Score compresses a company's financial statements into nine yes-or-no tests and adds up the passes. Eight or…
- Predetermined Overhead Rate & Applied Overhead CalculatorJob-order costing (ASC 330, IAS 2)Manufacturing overhead cannot be traced to a job the way steel or labour hours can, so you charge it with a rate fixed before…
Business, Marketing & E-commerce 2 calculators
- Payment Processing Fee Calculator (Stripe / PayPal)Percentage-plus-fixed card pricingCard processors charge a percentage of the transaction plus a flat amount per transaction, so the fee you actually pay depends…
- Price Elasticity of Demand CalculatorArc (midpoint) elasticity of demandEnter the price and unit volume before and after a price change and this calculator returns the price elasticity of demand by…
Computing, IT, Networking & Security 2 calculators
- Password Crack Time CalculatorOWASP Password Storage Cheat SheetAn offline brute-force attack is arithmetic, not magic. The attacker searches a keyspace of C L candidates at a rate set by the…
- Password Entropy CalculatorNIST SP 800-63BEntropy measures how many equally likely passwords an attacker has to search, expressed as a power of two. A password drawn…
Health, Fitness & Nutrition 2 calculators
- Pregnancy Due Date CalculatorNaegele's rule; ACOG Committee Opinion 700 dating conventionsThis calculator gives you an estimated due date and tells you exactly how many weeks and days pregnant you are today. Date from…
- Protein Intake CalculatorIOM Dietary Reference Intakes and the ISSN position stand on protein and exerciseProtein requirements scale with body size and with what you are asking your body to do, so the answer is a range rather than a…
Investing & Retirement 2 calculators
- Portfolio Rebalancing CalculatorEnter what each sleeve of your portfolio is worth and what you want it to be worth, and this calculator returns the exact…
- Present Value CalculatorThis calculator discounts money you will receive later back to what it is worth today. Give it a future lump sum, a stream of…
Machining, Welding & Metal Fabrication 2 calculators
- Press Brake Tonnage CalculatorAir-bend three-point force formulaA press brake bends sheet by pressing it into a V-shaped die, and the force that takes depends far more on the die opening than…
- Pulley Speed & Ratio CalculatorBelt-drive kinematics (Machinery's Handbook)Enter any three of the four quantities in a belt drive — driver sheave diameter, driver RPM, driven sheave diameter, driven RPM…
Personal Finance, Loans & Credit 2 calculators
- Pay Raise Percentage CalculatorFisher relation for real growthA raise has two sizes: the one on the letter and the one you keep after prices move. This calculator gives you both. Enter your…
- Personal Loan Payment CalculatorRegulation Z finance charge and APRA personal loan quote has two rates hiding in it. The note rate sets your payment; the origination fee, deducted from the money…
Professional Licensing & Applied Exam Math 2 calculators
- Pediatric Maintenance Fluid Calculator (4-2-1 Rule)Holliday-Segar method; AAP 2018 maintenance IV fluid guidelineEnter a child's weight and this calculator returns the maintenance intravenous fluid rate in mL per hour by the 4-2-1 rule and…
- Prescription Days Supply CalculatorThird-party billing days-supply conventionDays supply is the number of days a dispensed quantity will last at the prescribed directions, and it is the field most often…
Sports, Games, Gambling Odds & Hobbies 2 calculators
- Parlay Payout CalculatorMultiplicative decimal-odds combinationEnter each leg's price and your stake, and this calculator multiplies the decimal odds to give the combined parlay price, the…
- Poker Pot Odds CalculatorNo-limit hold'em pot-odds and indifference arithmeticEnter the pot before the bet, the bet you are facing and the amount you must put in, and this calculator returns the pot odds…