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Most-used calculators
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- 30-60-90 Triangle CalculatorA 30-60-90 triangle has its sides locked in the exact ratio 1 : √3 : 2, so one measurement gives you all of them with no…
- 3D Print Job Cost & Pricing CalculatorFull-absorption job costingFilament is the smallest cost in a 3D print job and the one everyone quotes on. This calculator adds the four costs that…
- 3D Printing Filament Length, Weight & Cost CalculatorCylindrical volume and material densityFilament is sold by weight, sliced by volume and measured on the spool by length, and converting between the three takes only…
- 401(k) Early Withdrawal Penalty CalculatorIRC §72(t)Cashing out a retirement account before age 59½ costs you three separate amounts: ordinary federal income tax on the whole…
- 401(k) Growth CalculatorIRC §402(g) & §415(c) contribution limitsThis calculator projects what your 401(k) will be worth on the day you retire. It compounds your existing balance monthly, adds…
- 529 College Savings CalculatorInternal Revenue Code §529 qualified tuition programsSaving for college is two projections that have to meet. This calculator grows your 529 balance and contributions forward to…
- 555 Timer CalculatorTI xx555 datasheet timing equationsEnter R1, R2 and the timing capacitor and this calculator returns the astable output frequency, period, high and low times and…
- 70% Rule Calculator70% rule (flipper's screening heuristic)The 70% rule sets a maximum purchase price on a flip in one line: take 70% of the after-repair value and subtract the repair…
- A/B Test Sample Size CalculatorTwo-proportion normal approximation (Fleiss)Enter your current conversion rate, the smallest lift worth acting on, and your daily traffic. You get the visitors each…
- A/B Test Statistical Significance CalculatorTwo-proportion z-test (pooled variance)Enter the visitors and conversions for your control and your variant, and this calculator runs the two-proportion z-test that…
- ACA Premium Tax Credit CalculatorIRC §36BThe ACA premium tax credit is not a percentage discount on your plan. It is the gap between the benchmark silver premium in…
- Accounting Equation CalculatorFASB Concepts Statement 8, Ch. 4Enter any two of the three balance-sheet totals and this calculator returns the third, then proves the answer against the…
- Accounts Receivable Turnover CalculatorUS GAAP statements (ASC 310) · 365-day yearReceivables turnover tells you how many times a year you sell on credit, collect the cash, and lend it out again. Enter net…
- Acid-Base Titration CalculatorStoichiometric equivalence, MₐVₐnₐ = M_bV_bn_bA titration converts a burette reading into a concentration. At the equivalence point the moles of titratable protons supplied…
- Acres to Hectares CalculatorInternational Yard and Pound Agreement (1959)Convert a parcel between acres, hectares, square feet, square meters and square miles using the exact factors that follow from…
- ACT Composite Score CalculatorACT scoring: composite as the rounded mean of section scaled scoresEnter your scaled ACT section scores and this calculator returns the composite exactly the way ACT computes it: the arithmetic…
- Actuarial Credibility Weighting CalculatorLimited fluctuation (classical) credibilityAn account with three claims does not tell you much; the same account with three thousand tells you a great deal. Credibility…
- Add & Subtract Time CalculatorSexagesimal (base-60) duration arithmeticAdd or subtract up to three durations written as hours, minutes and seconds, and get the answer in h:m:s, in decimal hours, in…
- Adding & Subtracting Fractions CalculatorEnter two fractions or mixed numbers and this calculator adds or subtracts them exactly — no rounding, no decimal drift. It…
- Age in Days, Hours & Minutes CalculatorFliegel–Van Flandern Julian Day NumberEnter a date of birth and this calculator returns the exact elapsed time to any reference date: total days, weeks, hours…
- Air Changes Per Hour (ACH) CalculatorASHRAE 62.1 / 62.2 ventilationAir changes per hour is airflow expressed as multiples of the room's own volume: 6 ACH means the fan moves six times the room's…
- Air Compressor CFM Requirement CalculatorSCFM referenced to 14.696 psia, 68 °FThis calculator sizes an air compressor the way a plant engineer does: it time-averages each tool's rated consumption by its…
- Air Conditioner BTU & Tonnage CalculatorAHAM / ENERGY STAR room AC sizing methodEnter the room's floor area and this calculator returns the cooling capacity it needs in BTU per hour and in tons, using the…
- Air Conditioner Running Cost CalculatorAHRI 210/240 and DOE 10 CFR 430 Appendix M1 ratingsThis calculator separates the two questions people ask about cooling cost and answers both. What does it cost while it is…
- Air Quality Index (AQI) CalculatorUS EPA Air Quality Index (40 CFR Part 58, Appendix G)The Air Quality Index converts a measured pollutant concentration into a number on a common 0–500 health scale, so that ozone…
- Airbnb / Short-Term Rental Revenue CalculatorHospitality revenue convention (ADR, occupancy, RevPAR)This calculator turns two numbers a host can actually observe — average daily rate and occupancy — into the figures that decide…
- Aircraft Weight & Balance CalculatorFAA-H-8083-1BEnter the weight and arm of every station on your aircraft and this calculator returns the loaded weight, the total moment and…
- Alimony & Spousal Support Calculator750 ILCS 5/504(b-1); Tex. Fam. Code §8.055There is no national alimony formula. What exists is a small number of published guideline formulas that courts and…
- Alligation Alternate CalculatorAlligation alternate; USP <795> compounding practiceAlligation answers one question: you have a stronger preparation and a weaker one, you need a specific strength in between, so…
- Altman Z-Score CalculatorAltman (1968, 1983, 1995) Z-Score modelsThe Altman Z-Score turns five balance-sheet and income-statement ratios into one number that says how closely a company…
- Amazon ACoS & TACoS CalculatorAmazon Ads reporting definitionsEnter your ad spend and your ad-attributed sales and this calculator returns your ACoS — advertising cost of sale — together…
- Amazon FBA Profit CalculatorSelling on Amazon fee schedule (US)This calculator turns an Amazon listing into the only three numbers that matter before you place a purchase order: net profit…
- Amdahl's Law Speedup CalculatorAmdahl (1967) and Gustafson (1988)Enter the fraction of your program that can run in parallel and the number of processors you plan to throw at it, and this…
- Anchor Rode & Scope CalculatorScope measured from bow roller to seabedScope is the ratio of rode deployed to the vertical distance from your bow roller down to the seabed — and that vertical…
- Anion Gap CalculatorSerum anion gap with Figge albumin correctionEnter a basic metabolic panel and this calculator returns the serum anion gap, the albumin-corrected gap, the delta gap, the…
- AP Exam Score CalculatorCollege Board AP composite scoring modelThis calculator rebuilds an AP exam score the way the College Board does it: it converts your multiple-choice and free-response…
- API Gravity Calculator (Specific Gravity, lb/gal & bbl per Ton)API MPMS Chapter 11.1 volume correction; API gravity defined at 60/60 °FAPI gravity is an inverted density scale built so that heavier oil gets a lower number and 10 °API is exactly the density of…
- Appliance Electricity Cost CalculatorkWh = W × h ÷ 1000Enter an appliance's power in watts (or its amps and volts), how long you run it, and what you pay per kilowatt-hour. You get…
- Arc Length CalculatorArc length is the distance measured along a curve rather than across it, and it is one multiplication away once the angle is in…
- Area Between Curves CalculatorA = ∫ |f(x) − g(x)| dx, split at each intersectionEnter two functions and this calculator finds every point where they cross inside your search window, integrates the gap…
- Arrhenius Equation CalculatorArrhenius equation, k = A·exp(−Ea/RT), R = 8.314463 J/(mol·K)The Arrhenius equation says a rate constant rises exponentially with temperature: k = A·e^(−Ea/RT). Enter the pre-exponential…
- Aspect Ratio CalculatorITU-R BT.709 / BT.2020 image formatsLock an aspect ratio, give one dimension, and this calculator returns the other one exactly. It also reduces any resolution to…
- Attendance Percentage CalculatorInstitutional minimum-attendance rule (course or programme policy)Enter the classes you have attended and the classes held so far and this calculator returns your attendance percentage, how…
- Attic Insulation Upgrade Payback CalculatorASHRAE degree-day method; IECC ceiling R-valuesHeat leaves a ceiling in direct proportion to area and temperature difference, and in inverse proportion to R-value. That last…
- Audio File Size CalculatorLinear PCM in WAV/RIFF; RF64 per EBU Tech 3306 above 4 GiBUncompressed audio has no surprises in it: the file size is exactly the sample rate times the bytes per sample times the…
- Auto Liability Coverage Limit CalculatorCCPA Title III garnishment cap (15 U.S.C. §1673)Liability limits are not sized against the car you drive. They are sized against what a plaintiff could collect from you if a…
- Auto Loan Payment CalculatorAmortised loan formula; Regulation Z finance-charge disclosureThe payment a dealer quotes is built from more than the sticker price. Sales tax, documentation and registration fees, and any…
- Available Static Pressure & Friction Rate CalculatorACCA Manual D friction rate procedureA blower produces a fixed amount of static pressure at its design airflow, and the filter, coil, humidifier, grilles and…
- Average Order Value (AOV) CalculatorMarketing Metrics (Farris et al.) definitionsAverage order value is revenue divided by orders — but the useful part is what you do with it. Enter your period revenue, order…
- Aviation Fuel Burn & Reserve Calculator14 CFR 91.151 / 91.167 fuel reservesThis calculator builds a complete fuel plan for one leg. Enter your cruise fuel flow, the distance and expected ground speed…
- Axle Gear Ratio & Final Drive CalculatorRing-and-pinion ratio identityEnter the tooth counts stamped on your ring gear and pinion and this calculator returns the axle ratio, the overall drive ratio…
- Babysitter Pay CalculatorFLSA §13(a)(15)Enter the time your sitter arrived and the time they left and this calculator turns the evening into a number you can hand over…
- Backup & Disaster Recovery Cost CalculatorAWS disaster recovery strategies; NIST SP 800-34 Rev. 1 (RPO/RTO)Recovery objectives are bought, not chosen. Every hour you shave off your recovery time objective costs more standing capacity…
- Baker's Percentage CalculatorBaker's percentage (flour = 100%)Baker's percentage expresses every ingredient in a bread formula as a percentage of the total flour weight, with flour itself…
- Baking Pan Size Conversion CalculatorPan area scalingSwapping a 9×13 for two 8-inch rounds is not a guess — it is a ratio of two areas. This calculator works out the baking surface…
- Bank Reconciliation CalculatorASC 305 cash · UCC Article 4 statement reviewEnter your bank statement balance and your general ledger cash balance and this calculator works both columns of the…
- Base Conversion CalculatorPositional notation, radix 2 to 36Type a value, say what base it is written in, and choose the base you want it in. This converter handles every radix from 2 to…
- Basic Earnings Per Share CalculatorASC 260 / IAS 33Basic earnings per share looks like a one-line division and almost never is, because the denominator has to be time-weighted…
- Battery Bank Sizing CalculatorIEEE 1013 sizing practiceEnter what you use in a day, how many days you want to ride through without charging, and how deeply you are willing to…
- Battery Runtime CalculatorPeukert's law (IEC 61056 hour-rate basis)Give this calculator a battery's amp-hour rating, its voltage, and the load in watts, and it returns the runtime in hours along…