🧮Calculators
Calculators cover finance, health, math, physics, engineering and everyday life: interest and loans, net salary, BMI, rule of three, conversions and more. Results are informational and educational — for important decisions, confirm with a professional and official sources.
2826 tools
Brazilian Incentivized Debenture Yield Calculator
Estimates the net equivalent yield of a Brazilian IR exempt incentivized debenture vs a taxed CDB paying a percent of CDI under the regressive table.
CEFR Language Learning Time Calculator
Estimates hours of study to reach a CEFR level (A1 to C2) in a language based on FSI difficulty category for Portuguese native speakers.
Vocabulary Size for Fluency Calculator
Estimates passive vocabulary size needed to reach a target text coverage in a language using an approximate Zipf law model.
Foreign Language Page Reading Time Calculator
Estimates how long a reader takes to read a page in a foreign language based on current CEFR level and number of words on the page.
Zipf Law Word Frequency Calculator
Computes the relative estimated frequency of a word in a corpus by Zipfs law (1/rank) from the word rank in the chosen language.
Romance Language Lexical Similarity Calculator
Estimates approximate lexical similarity between two Romance languages from known tables for Portuguese, Spanish, Italian, French and Romanian.
Document Translation Time Estimator
Estimates total time a professional translator takes to translate a document given total words and average pace in words per hour.
Translation Review Time Estimator
Estimates total time a reviewer takes to review a translation from word count and average review pace in words per hour.
Tuning Cents Deviation Calculator
Computes pitch deviation in cents between two musical frequencies using 1200 * log2(measured / reference).
Guitar String Vibration Frequency Calculator
Computes the fundamental frequency of a guitar string from vibrating length, tension and linear mass density via f = (1/2L) sqrt(T/mu).
Guitar String Tension by Mass Calculator
Computes required tension in newtons on a guitar string for a given fundamental frequency from string length and linear mass density.
Violin String Tension Calculator
Computes tension in newtons needed on a violin string to produce a fundamental frequency from vibrating length and linear mass density.
Flute Pipe Length for Frequency Calculator
Computes approximate length of an open flute pipe to emit a fundamental note using L = c / 2f with sound speed 343 m/s in air.
Closed Pipe Organ Length Calculator
Computes approximate length of a closed pipe organ tube to emit a fundamental frequency using L = c / 4f in atmospheric air.
Drum Membrane Diameter Calculator
Computes approximate radius of an ideal circular drum membrane for a fundamental frequency using first mode (alpha_01 = 2.404) and transverse wave speed.
Piano Sustained Note Decay Calculator
Computes exponential amplitude decay of a piano note with the sustain pedal released using typical half-life of the note and elapsed time.
Orchestra Tuning Time Calculator
Estimates total tuning time of a full orchestra before a concert from number of musicians per section and average time per musician.
Pizzicato String Audible Decay Calculator
Estimates audible vibration time of a plucked open string in guitar or violin from oscillator quality factor Q and fundamental frequency.
Audio Beat Frequency Calculator
Computes the beat frequency perceived when playing two close notes simultaneously from both frequencies in Hertz, useful for tuning by ear.
Overtone Harmonic Series Calculator
Computes the first N overtones of a fundamental frequency listing each integer multiple frequency and interval in cents from the fundamental.
Sealed Subwoofer Box Volume Calculator
Computes optimal sealed subwoofer box volume via Vb = Vas / (Qtc^2/Qts^2 - 1) from speaker Thiele Small parameters.
Bitcoin Satoshi BTC Converter
Converts between satoshi and BTC knowing that 1 BTC equals 100 million satoshis for wallet and crypto calculations.
Ethereum Gwei ETH Wei Converter
Converts between wei, gwei and ETH knowing 1 ETH equals 1e9 gwei and 1e18 wei for smart contract and gas fee calculations.
Ethereum Gas Cost Calculator
Computes total Ethereum transaction cost in ETH and USD from gas used, gas price in gwei and ETH USD quote.
Mining Hash Rate Converter
Converts hash rate between H s, KH s, MH s, GH s, TH s, PH s and EH s for ASIC and GPU mining comparison.
Mining Watt Revenue Calculator
Estimates daily bitcoin mining revenue from TH s, watts consumed, kWh cost and expected gross revenue per TH s per day.
Staking Yield APY Monthly Calculator
Computes equivalent monthly and daily yield from staking APY and the principal amount applied in tokens.
DeFi Liquidity Pool TVL Calculator
Computes total TVL and per LP token value of a DeFi liquidity pool from both asset amounts, prices and LP supply.
DeFi Impermanent Loss Calculator
Computes impermanent loss of a 50 50 DeFi pool between two assets from the ratio of final price divided by initial price.
NFT Royalty Arbitrum Calculator
Computes net NFT sale revenue on Arbitrum after creator royalty, marketplace fee and approximate gas cost.
Bitcoin Block Time Calculator
Computes approximate time to mine N bitcoin blocks adopting the 10 minute average target per block kept by difficulty adjustment.
Ethereum Block Time Calculator
Computes approximate time to mine N Ethereum blocks post merge adopting the 12 second average per slot of Beacon Chain.
Bitcoin Halving Date Calculator
Computes approximate next bitcoin halving date from current block and halving target block using 10 minute block time.
Spectrum Attribute Clash Calculator
Computes how many 8x8 attribute clash regions exist on a 256x192 pixel ZX Spectrum screen used by the famous color hardware issue.
Amiga OCS Palette Calculator
Computes simultaneous colors and required bitplanes for Amiga Original Chip Set video modes per chosen horizontal width.
Apple II Hi Res Resolution Calculator
Computes pixels and bytes occupied by Apple II hi res 280x192 screen with 6 active bits per byte and color bytes per line.
MSX1 VDP VRAM Calculator
Computes VRAM usage on MSX1 TMS9918 VDP in graphic 1, graphic 2 and text modes including pattern table and sprite attribute table.
TRS-80 Model I Charset Calculator
Computes the 5x7 bytes of each TRS-80 Model I character given its ASCII code presenting the 7 bytes forming the character rows.
Book Pages By Words Calculator
Estimates book pages from total words and book type (pocket, trade, hardcover, textbook) which defines words per page.
Book Writing Time Calculator
Computes days and months to write a book with a target word count from the daily pace given in words per day.
Flesch Portuguese Readability Calculator
Computes Flesch reading ease index for Portuguese from total words, syllables and sentences already counted by the writer.
Gunning Fog Index Calculator
Computes Gunning Fog reading complexity index from words, sentences and complex words with three or more syllables in the text.
SMOG Readability Calculator
Computes SMOG (Simple Measure of Gobbledygook) readability index from total polysyllabic words in a 30 sentence text sample.
Automated Readability Index Calculator
Computes Automated Readability Index (ARI) from characters, words and sentences returning approximate reader grade level.
Dale Chall Readability Calculator
Computes Dale Chall readability index from percentage of difficult words (outside the 3000 common word list) and average sentence length.
Novel Reading Time Calculator
Estimates total reading time of an N page novel based on standard words per page and typical adult Portuguese reading speed.
Portuguese Common Word Frequency Calculator
Shows estimated relative frequency of very common Portuguese words from corpus lists and indicates where it falls in the top thousand.
Paragraphs Per Page Calculator
Estimates paragraphs per book page based on work type (novel, nonfiction, textbook) and average paragraph length in lines.
Novel Character Count Calculator
Suggests typical number of named, secondary and extra characters in a novel based on given literary genre (fantasy, romance, noir, etc).
Book Chapter Count Calculator
Computes suggested chapter count for a book based on total words and average words per chapter of given genre.
Egypt Pyramid Build Time Calculator
Estimates Egyptian pyramid construction time from volume in cubic meters and daily average rate of stones laid by workers.
Khufu Pyramid Stones Calculator
Computes approximate stone block count of Great Pyramid of Khufu from 2.5 million m3 volume and average block size.
Statue Of Liberty Height Calculator
Converts and compares total Statue of Liberty height in meters, centimeters, feet, inches and multiples of average human height.
Historic Train Speed Calculator
Compares typical speeds of famous historic trains (1830 Rocket, 1870 Pony, 1981 TGV, 1964 Shinkansen) in km h and mph for trivia.
Horse Carriage Speed Calculator
Computes typical speed of different horse drawn carriages in 19th century in km h from number of horses and carriage type.
Pony Express Delivery Time Calculator
Computes approximate Pony Express historic delivery time between St Joseph Missouri and Sacramento California from miles.
Library Of Alexandria Books Calculator
Estimates papyrus scrolls and modern equivalent books at the Library of Alexandria from up to 700000 scrolls historic estimate.
Great Wall Build Years Calculator
Computes total Great Wall of China construction time from length in km and average meters of wall raised per year by workers.
Great Wall Workers Calculator
Estimates how many workers were needed to build the Great Wall of China from total structure volume and average rate per worker year.
Colosseum Rome Build Time Calculator
Computes total Colosseum of Rome construction time from cubic meter volume and daily average stone placed by workers.