All Games
191Math
21Arithmetic5
SpeedMath
ExactRace through arithmetic. Addition, subtraction, multiplication, and more.
Percentage Pro
ClosenessCalculate percentages, discounts, and markups in your head.
Fraction Blitz
ClosenessMaster fractions: convert, add, subtract, multiply, and divide.
Order of Operations
ExactMaster PEMDAS with expressions that punish left-to-right guessing.
Mental Multiply
ExactMulti-digit mental multiplication under time pressure.
Estimation5
The Total Is
ClosenessWatch prices flash by. Estimate the total.
Square Root Estimation
ClosenessEstimate square roots to the nearest hundredth.
Logarithm Estimation
ClosenessEstimate logarithm values in different bases.
Power Estimation
ClosenessEstimate powers and exponentials from memory.
Ratio Estimation
ClosenessEstimate ratios and proportions from given quantities.
Number Theory5
Square & Root
ExactPowers, squares, cubes, and square roots. Mental math fundamentals.
Prime Hunter
ExactFind primes, count primes, and master number theory.
Sequence Solver
ExactFind the pattern and predict the next number in the sequence.
Scientific Notation
ExactConvert between scientific notation and standard form.
GCD & LCM
ExactCalculate greatest common divisors and least common multiples.
Statistics6
Mean Machine
ClosenessCalculate the average (mean) of a dataset. Mental arithmetic meets statistics.
Median Finder
ClosenessFind the middle value in a dataset. Sort, locate, calculate.
Standard Deviation
ClosenessCalculate the population standard deviation of a dataset.
Probability Pop
ClosenessCalculate probabilities for dice, coins, cards, and more.
Combinatorics
ExactFactorials, permutations, and combinations.
Z-Score
ClosenessCalculate and interpret z-scores in normal distributions.
Finance
15Investing9
Compound Interest
ClosenessFuture value, present value, and the Rule of 72. Know what your money is actually doing.
P/E Ratio
ClosenessPrice-to-earnings ratio calculations. Value investing fundamentals.
Dividend Yield
ClosenessCalculate dividend yields and income from stocks. Income investing fundamentals.
CAGR
ClosenessCompound Annual Growth Rate. Normalize investment returns across different time periods.
Dollar Cost Average
ClosenessCalculate average cost basis from multiple purchases at different prices.
Options Intrinsic Value
ExactCalculate intrinsic value of call and put options.
Options Breakeven
ExactCalculate breakeven prices for option trades.
Bond Yield
ClosenessCalculate current yield and approximate yield to maturity for bonds.
Portfolio Return
ClosenessCalculate weighted portfolio returns and risk metrics.
Loans & Mortgages6
Monthly Payment
ClosenessCalculate mortgage and loan monthly payments using the standard amortization formula.
Total Interest Paid
ClosenessCalculate the lifetime interest cost on a loan.
Payoff Accelerator
ClosenessCalculate time and interest saved by making extra payments on loans.
Refinance Math
ClosenessCalculate break-even month and savings when refinancing a loan.
Amortization Split
ClosenessBreak down loan payments into interest and principal components.
APR vs Rate
ClosenessCalculate effective annual rate from nominal rate and compounding frequency.
Everyday
15Bills & Tips5
Tip Calculator
ClosenessCalculate tips, split bills, and figure out your share. No phone allowed.
Split the Bill
ClosenessCalculate your fair share when dining with others. Tax, tip, and shared items.
Auto Loan Payment
ClosenessCalculate monthly car loan payments with interest.
Utility Bill
ClosenessCalculate electric, gas, and water bills from usage rates and tiered pricing.
Subscription Cost
ClosenessCompare monthly vs annual plans, bundle costs, and family plan savings.
Taxes & Income5
Tax Bracket
ClosenessCalculate federal income tax using 2024 US tax brackets.
Paycheck Math
ClosenessCalculate take-home pay from gross salary after taxes and deductions.
Auto Sales Tax
ClosenessCalculate sales tax on vehicle purchases.
Hourly to Annual
ClosenessConvert hourly wages to annual salary with overtime, benefits, and deductions.
Sales Tax Compare
ClosenessCompare total costs across different tax rates and categories.
Shopping & Deals5
Discount Stack
ClosenessMultiple discounts, coupons, and BOGO deals. How much do you actually pay?
Lease vs Buy
ClosenessCompare total costs of leasing versus buying a vehicle.
Unit Price
ClosenessCompare unit prices across package sizes to find the best deal.
Coupon Stack
ClosenessStack percentage and dollar-off coupons. Order matters!
Cashback Rewards
ClosenessCalculate credit card cashback on categorized spending.
Vehicles
15Fuel Economy5
Cost Per Mile
ClosenessCalculate how much each mile costs in fuel. Know your true driving expenses.
Road Trip Cost
ClosenessCalculate fuel costs for road trips. Plan your budget before you drive.
MPG from Trip Data
ClosenessCalculate your real fuel efficiency from actual trip data.
Fuel Tank Range
ClosenessCalculate how far you can drive on a tank of gas.
Fill-Up Cost
ClosenessCalculate the cost to fill your tank at the gas pump.
Electric Vehicles5
EV vs Gas Savings
ClosenessCompare annual fuel costs between electric and gas vehicles.
EV Range
ClosenessCalculate electric vehicle driving range from battery and efficiency.
EV Charging Cost
ClosenessCalculate the cost to charge an electric vehicle at home or on the road.
Charging Time
ClosenessCalculate how long it takes to charge an electric vehicle.
EV Battery Degradation
ClosenessCalculate battery capacity loss over time and charge cycles.
Ownership Costs5
Depreciation
ClosenessCalculate how much a vehicle loses in value over time.
Total Cost of Ownership
ClosenessCalculate the true 5-year cost of owning a vehicle.
Cost Per Year
ClosenessCalculate the annualized cost of owning a vehicle.
Insurance Cost
ClosenessCalculate annual vehicle insurance premiums with various factors.
Lease Payment
ClosenessCalculate monthly vehicle lease payments with various terms.
Measurement
35Length5
Length
ClosenessConvert between cm, m, km, inches, feet, yards, and miles.
Length Chain Conversion
ClosenessConvert lengths through multiple units in sequence.
Length Word Problems
ClosenessSolve real-world length conversion word problems.
Length Comparison
ClosenessCompare two lengths in different units and find the difference.
Length Estimation
ClosenessEstimate length measurements using real-world references.
Mass5
Mass
ClosenessConvert between grams, kilograms, ounces, and pounds.
Mass Chain Conversion
ClosenessConvert masses through multiple units in sequence.
Mass Word Problems
ClosenessSolve real-world mass conversion word problems.
Mass Comparison
ClosenessCompare two masses in different units and find the difference.
Mass Estimation
ClosenessEstimate mass measurements using real-world references.
Volume5
Volume
ClosenessConvert between mL, liters, fluid ounces, cups, pints, quarts, and gallons.
Volume Chain Conversion
ClosenessConvert volumes through multiple units in sequence.
Volume Word Problems
ClosenessSolve real-world volume conversion word problems.
Volume Comparison
ClosenessCompare two volumes expressed in different units.
Volume Estimation
ClosenessEstimate volumes using real-world references.
Speed5
Speed
ClosenessConvert between m/s, km/h, mph, and ft/s.
Speed Chain Conversion
ClosenessConvert speeds through multiple units in sequence.
Speed Word Problems
ClosenessSolve real-world speed conversion word problems.
Speed Comparison
ClosenessCompare two speeds expressed in different units.
Speed Estimation
ClosenessEstimate speeds using real-world references.
Time5
Time
ClosenessConvert between seconds, minutes, hours, days, and weeks.
Time Chain Conversion
ClosenessConvert time through multiple units in sequence.
Time Word Problems
ClosenessSolve real-world time conversion word problems.
Time Comparison
ClosenessCompare two time durations expressed in different units.
Time Estimation
ClosenessEstimate time durations using real-world references.
Temperature5
Temperature
ClosenessConvert between Celsius and Fahrenheit.
Temperature Chain Conversion
ClosenessConvert temperature through multiple scales in sequence.
Temperature Word Problems
ClosenessSolve real-world temperature conversion word problems.
Temperature Comparison
ClosenessCompare two temperatures expressed in different scales.
Temperature Estimation
ClosenessEstimate temperatures using real-world references.
All Units5
All Units
ClosenessConvert between all unit types: length, mass, volume, speed, time, and temperature.
Mixed Chain Conversion
ClosenessMulti-step conversions across all unit types.
Mixed Word Problems
ClosenessWord problems from all unit categories.
Mixed Compare
ClosenessCompare quantities from any unit category.
Mixed Estimation
ClosenessEstimation challenges from any unit category.
Sports
60Baseball6
Baseball Batting
ClosenessCalculate batting average, OBP, slugging, OPS, and more from realistic stat lines.
Baseball Pitching
ClosenessCalculate ERA, WHIP, K/9, and more from realistic pitching lines.
Baseball Fielding
ClosenessCalculate fielding percentage, range factor, and more from realistic fielding stats.
Baseball Baserunning
ClosenessCalculate stolen base rates, runs created, and baserunning metrics.
Baseball Sabermetrics
ClosenessCalculate WHIP, ERA, K/9, BB/9, and advanced pitching metrics from season stats.
All Baseball
ClosenessMixed baseball stats from batting, pitching, fielding, baserunning, and sabermetrics.
Basketball6
Basketball Stats
ClosenessCalculate FG%, TS%, eFG%, fantasy points, and more from realistic box scores.
Basketball Shooting
ClosenessCalculate 2P%, 3P%, FT%, points per shot, eFG%, and TS% from shooting splits.
Basketball Advanced
ClosenessCalculate usage rate, game score, and per-36 stats from advanced box scores.
Basketball Rebounding
ClosenessCalculate ORB%, DRB%, rebound rate, and per-game rebounding stats.
Basketball Playmaking
ClosenessCalculate assist/turnover ratio, assist rate, and playmaking metrics.
All Basketball
ClosenessMixed basketball stats from shooting, advanced, rebounding, playmaking, and more.
American Football6
Football Passing
ClosenessCalculate completion percentage, passer rating, and more from realistic QB stat lines.
Football Rushing
ClosenessCalculate yards per carry, fantasy points, and more from realistic RB stat lines.
Football Receiving
ClosenessCalculate catch rate, yards per reception, PPR fantasy points, and more from realistic WR/TE stat lines.
Football Defense
ClosenessCalculate tackle rate, sack rate, INT rate, and QB pressure percentage from defensive stat lines.
Football Special Teams
ClosenessCalculate field goal percentage, punt average, return average, and touchback rate from special teams stats.
All Football
ClosenessMixed American football calculations across passing, rushing, receiving, defense, and special teams.
Cricket6
Cricket Batting
ClosenessCalculate batting average, strike rate, and more from realistic cricket batting stats.
Cricket Bowling
ClosenessCalculate economy rate, bowling average, and more from realistic bowling figures.
Cricket Fielding
ClosenessCalculate catch success rate, run-out efficiency, and stumping rate from fielding stats.
Cricket Economy
ClosenessCalculate economy rate, dot ball percentage, and maiden over rate from bowling economy stats.
Cricket All-Rounder
ClosenessCalculate all-rounder index, batting-bowling ratio, and combined batting+bowling value.
All Cricket
ClosenessMixed cricket calculations across batting, bowling, fielding, economy, and all-rounder stats.
Tennis6
Tennis Match Stats
ClosenessCalculate first serve percentage, break points, and more from realistic match statistics.
Tennis Serving
ClosenessCalculate ace percentage, double fault rate, serve win percentages, and hold rates.
Tennis Returning
ClosenessCalculate return games won, break point conversion, and return point statistics.
Tennis Rally
ClosenessCalculate winners/UE ratio, net approach success, and aggression metrics.
Tennis Match Efficiency
ClosenessCalculate sets won, tiebreak win rate, deciding set records, and match efficiency stats.
All Tennis
ClosenessMixed tennis statistics from serving, returning, rally, match efficiency, and general match stats.
Soccer6
Soccer Stats
ClosenessCalculate goals per game, shot accuracy, xG difference, and more from realistic season stats.
Soccer Goalkeeping
ClosenessCalculate save percentage, goals against average, clean sheet rate, and more.
Soccer Defensive
ClosenessCalculate tackle success, interceptions per 90, aerial duels, and defensive action rates.
Soccer Possession
ClosenessCalculate pass completion, progressive passes per 90, key passes, and carrying stats.
Soccer Attacking
ClosenessCalculate shot conversion, xG overperformance, chances created per 90, and goal involvement.
All Soccer
ClosenessMixed soccer statistics from attacking, defending, goalkeeping, possession, and general stats.
Golf6
Golf Stats
ClosenessCalculate scoring average, GIR percentage, scrambling, and more from realistic tournament stats.
Golf Scoring
ClosenessCalculate scoring average, par averages, birdie percentage, and bogey avoidance from tournament data.
Golf Driving
ClosenessCalculate driving accuracy, average distance, fairway hit rate, and distance differential.
Golf Putting
ClosenessCalculate putts per GIR, 1-putt percentage, 3-putt percentage, and total putts per round.
Golf Approach
ClosenessCalculate GIR percentage, proximity to hole, sand save percentage, and up-and-down rate.
All Golf
ClosenessMixed golf calculations from stats, scoring, driving, putting, and approach games.
Hockey6
Hockey Stats
ClosenessCalculate goals per game, shooting percentage, save percentage, GAA, Corsi, and PDO from realistic stat lines.
Hockey Scoring
ClosenessCalculate points per game, even-strength production, power play percentage, and shooting percentage.
Hockey Goaltending
ClosenessCalculate GAA, save percentage, shutout rate, and quality start percentage from goalie stats.
Hockey Possession
ClosenessCalculate Corsi%, Fenwick%, zone start%, and PDO from advanced hockey stats.
Hockey Special Teams
ClosenessCalculate power play%, penalty kill%, shorthanded goals/60, and 5v5 goal differential.
All Hockey
ClosenessMixed hockey calculations from stats, scoring, goaltending, possession, and special teams.
Motorsports6
Motorsports Stats
ClosenessCalculate win rate, average finish, pole-to-win conversion, and more from realistic motorsport stat lines.
Motorsports Qualifying
ClosenessCalculate qualifying deltas, lockout rates, and position averages from realistic qualifying data.
Motorsports Race Pace
ClosenessCalculate average lap times, pit stop deltas, tire degradation rates, and more from realistic race data.
Motorsports Championship
ClosenessCalculate points projections, constructor totals, and championship gaps from realistic standing data.
Motorsports Pit Strategy
ClosenessCalculate optimal pit windows, undercut/overcut deltas, and strategy comparisons from realistic race data.
All Motorsports
ClosenessMixed motorsport calculations from all sub-categories: stats, qualifying, race pace, championship, and pit strategy.
Combat Sports6
Combat Sports Stats
ClosenessCalculate win rate, KO rate, striking accuracy, takedown accuracy, and more from realistic MMA stat lines.
Combat Striking
ClosenessCalculate striking accuracy, absorbed strikes per minute, and strike differential from realistic MMA data.
Combat Grappling
ClosenessCalculate takedown accuracy, submission rate, and control time percentage from realistic MMA grappling data.
Combat Judging
ClosenessCalculate 10-point must scoring, split decisions, and judge totals from realistic MMA judging data.
Combat Record
ClosenessCalculate win percentage, finish rate, average fight time, and KO rate from realistic fighter records.
All Combat Sports
ClosenessMixed combat sports calculations from all sub-categories: stats, striking, grappling, judging, and record.
Chemistry
12Periodic Table6
Atomic Number
ExactGiven an element name or symbol, type its atomic number
Atomic Mass
ClosenessGiven an element, type its atomic mass
Electron Config Count
ExactCount electrons in a specific shell or subshell
Valence Electrons
ExactHow many valence electrons does this element have?
Oxidation State
ExactWhat is the most common oxidation state of this element?
All Periodic Table
ClosenessMixed periodic table questions
Chemical Calculations6
Molar Mass
ClosenessCalculate the molar mass of a compound
pH Calculator
ClosenessCalculate pH from hydrogen ion concentration
Molarity
ClosenessCalculate solution concentration from mass, molar mass, and volume
Stoichiometry
ClosenessCalculate molar ratios from balanced equations
Gas Laws
ClosenessBoyle's, Charles's, Combined, and Ideal gas law
All Chemistry Calc
ClosenessMixed chemistry calculations
Physics
18Mechanics6
Kinematics
ClosenessSolve motion equations: velocity, displacement, and acceleration
Force Calculator
ClosenessCalculate forces using Newton's laws
Energy
ClosenessCalculate kinetic energy, potential energy, and work
Gravity
ClosenessCalculate gravitational forces and field strength
Momentum
ClosenessMomentum, impulse, and collision calculations
All Mechanics
ClosenessMixed mechanics calculations: kinematics, forces, energy, gravity, and momentum
Waves & Circuits6
Wave Speed
ClosenessCalculate wave speed, frequency, and wavelength
Circuit Solver
ClosenessSolve electrical circuits using Ohm's law and resistance networks
Sound Intensity
ClosenessCalculate sound intensity levels in decibels
Optical Lens
ClosenessThin lens equation and magnification calculations
Resonance Frequency
ClosenessLC circuits, pipe harmonics, and standing waves
All Waves & Circuits
ClosenessMixed wave, circuit, sound, lens, and resonance calculations
Physical Constants6
Constants Quiz
ClosenessRecall fundamental physics constants
Speed of Light Problems
ClosenessApplications of the speed of light (c = 3×10⁸ m/s)
Gas Constant Problems
ClosenessIdeal gas law PV = nRT applications
Gravity Constant Problems
ClosenessGravitational force and orbital mechanics using G
Planck Constant Problems
ClosenessE=hf, photoelectric effect, and de Broglie wavelength
All Constants
ClosenessMixed physics constants: recall, speed of light, gas law, gravity, and Planck