🧮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
Paint Calculator
Calculate how many liters of paint you need for an area (walls, ceiling). Considers coats, coverage per liter and discounts for doors/windows. Everything in your browser.
Tile Calculator
Calculate how many m² of flooring or tile boxes to buy. Includes safety margin (10%, 15%, 20%) for cuts and breakage. Everything in your browser.
Cement and Sand Calculator
Calculate cement bags, sand and gravel for concrete, screed and mortar by ratio (1:3, 1:4, 1:6, etc.). Everything in your browser.
BTU (AC) Calculator
Calculate the ideal BTU/h power for a room — based on area, people, electronics and sun exposure. Everything in your browser.
Battery Life Calculator
Estimate how long a battery (mAh or Wh) lasts given the circuit consumption (mA or W). Includes discharge derating. Everything in your browser.
Solar Panel Calculator
Estimate how many solar panels (Wp) you need to offset monthly electricity consumption (kWh) of a home. Everything in your browser.
Kinetic Energy Calculator
Compute kinetic energy KE = ½ m v² from mass (kg) and velocity (m/s). Result in joules.
Potential Energy Calculator
Compute gravitational potential energy PE = m g h with mass (kg), g and height (m).
Linear Momentum Calculator
Compute linear momentum p = m·v from mass (kg) and velocity (m/s).
Work (Physics) Calculator
Compute work W = F·d·cos(θ). Force in N, displacement in m, angle in degrees.
Average Velocity Calculator
Compute average velocity v = Δs/Δt from distance and time, in km/h or m/s.
Acceleration Calculator
Calculate the average acceleration of an object with the formula a = (v − v₀)/t. Enter the initial and final velocities in m/s and the time in seconds.
Density Calculator
Compute density ρ = m/V with mass in g and volume in mL. Result in g/mL.
Pressure Calculator
Compute pressure P = F/A with force in N and area in m². Result in Pa, kPa, bar.
Decibel Calculator
Compute decibel ratio: 20·log10(P/Pref) for power or 10·log10(I/Iref) for intensity.
Wave Calculator
Compute v = λ·f from any two of: velocity, wavelength, frequency.
Doppler Effect Calculator
Compute observed frequency in Doppler effect for moving source/observer (sound, c=343 m/s).
Mole Calculator
Compute moles n = m/M (mass / molar mass). Useful for chemistry homework.
Dilution Calculator
Solve the dilution equation C₁V₁ = C₂V₂. Provide any three values to compute the fourth.
pH/pOH Calculator
Convert between [H⁺], [OH⁻], pH and pOH using pH = -log[H⁺] and pH + pOH = 14.
Vector Magnitude Calculator
Compute 3D vector magnitude |v| = √(x² + y² + z²). For 2D leave z=0.
Matrix Determinant 2×2 / 3×3
Compute determinant of 2×2 and 3×3 matrices using Sarrus rule.
Matrix Multiplication
Multiply two matrices A and B (compatible dimensions) and show C = A·B.
3D Distance Calculator
Compute Euclidean distance between two 3D points.
1RM Calculator
Estimate one-rep max from weight × reps using Epley: 1RM = w · (1 + 0.0333·r).
Steps to Distance Calculator
Convert step count to kilometers using stride length (cm). Default 75 cm.
Blood Glucose Converter
Convert blood glucose between mg/dL and mmol/L using factor 18.0182.
Bitrate Calculator
Compute bitrate = filesize × 8 / duration. Result in kbps and Mbps.
Download Time Calculator
Estimate download time from file size and connection speed.
Video Storage Calculator
Estimate video storage from bitrate and duration.
Uptime / SLA Calculator
Convert uptime SLA percent (99.9% etc.) into allowed downtime per day/week/month/year.
GPA Calculator
Compute weighted GPA from grades and credits, one per line.
Required Final Grade Calculator
Compute the minimum final exam grade needed to reach a target average.
Escape Velocity Calculator
Compute escape velocity (v = √(2GM/r)) for any body. Presets for Earth, Moon, Mars, Jupiter, Sun — or custom.
Thin Lens Calculator
Apply the thin lens equation: 1/f = 1/p + 1/q. Solve for image distance given p and f, or focal length given p and q. Shows magnification.
Coulomb’s Law Calculator
Compute the electric force between two point charges: F = k·|q1·q2|/r². Supports C, mC, µC, nC.
Magnetic Flux Calculator
Compute magnetic flux Φ = B·A·cos(θ) through a uniform field over an area. Result in Webers (Wb).
Series & Parallel Resistance Calculator
Compute equivalent resistance of up to 10 resistors in series (sum) or parallel (1/Σ(1/R)). Accepts Ω, kΩ, MΩ.
Series & Parallel Capacitor Calculator
Compute equivalent capacitance in series (1/Σ(1/C)) or parallel (sum). Inverse of resistor rule.
Series & Parallel Inductor Calculator
Compute equivalent inductance: series sums (L=L1+L2+...) and parallel is 1/Σ(1/L). Same rule as resistors. In Henry (H).
Regular Polygon Calculator
Compute area, perimeter, apothem and interior angle of regular polygons (3-100 sides) given side or circumradius.
Mixed (Hamburg) Interest Calculator
Compute interest using the Hamburg method — used in checking accounts: applies interest on balance per movement, summing debits/credits per day.
CDI Yield Calculator
Compute net yield of CDI-linked investment. Accepts % of CDI (e.g., 110%), term, IR (regressive table) and IOF.
Brazilian Savings Yield Calculator
Compute Brazilian "poupança" yield (current rule: 70% Selic if ≤8.5%, or 0.5%/month + TR). Monthly and final values over N months.
Selic Yield Calculator
Compute Tesouro Selic (LFT) yield — annual Selic rate, term in days, with regressive IR. Shows gross, tax and net.
Debt Snowball Calculator
Simulate paying off a debt with the "snowball" method — minimum payment + extra monthly. Shows months to free and total interest.
Trade-off Calculator
Score multiple options against weighted criteria. Each option gets 0-10 ratings, weighted. Output: final ranking.
Goal Progress Calculator
Compute % done of a goal, projection to period end, and pace needed to finish on time. For sales, reading, training goals.
Fuel Savings Calculator
Compute trip cost and savings vs another vehicle (more/less efficient). Shows savings in $ and liters.
Projectile Max Height Calculator
Compute max height, range and flight time of an obliquely launched projectile (v0 and angle θ). No air drag (g=9.81 m/s²).
Annual ⇄ Monthly Rate Converter
Convert between equivalent annual, monthly and daily rates (compound): (1+i)ⁿ. E.g., yearly to monthly equivalent.
Cutoff by Percentile Calculator
Given a set of scores and a cutoff percentile (e.g., top 10%), compute the minimum score to make the cut. Useful for college admissions, HR.
Wire Resistance Calculator
Compute conductor resistance R = ρL/A.
LED Resistor Calculator
Compute LED current-limiting resistor R = (V_supply − V_LED)/I_LED with dissipated power.
Capacitors in Series
Compute equivalent capacitance of series capacitors. Values in μF, one per line.
Capacitors in Parallel
Sum capacitances of parallel capacitors. Values in μF, one per line.
Inductors in Series
Sum inductances in series or parallel. Values in mH.
Power Factor Calculator
Compute power factor cos(φ) = P/S and angle from active (W) and apparent (VA) power.
Photon Energy Calculator
Compute photon energy E = h·c/λ from wavelength in nanometers.
Wind Chill Calculator
Compute Wind Chill (NWS formula, T ≤ 10°C and wind ≥ 5 km/h).