Solve any equation forward or backward—click any variable to make it the target with automatic SI unit conversions.
Solve for future value, initial principal, annual compound growth rate (CAGR), or investment horizon.
Calculate non-compounded interest accrued, principal required, annual interest rate, or loan duration.
Solve for monthly equated installment (EMI), maximum affordable loan principal, annual interest rate, or loan tenure.
Bidirectionally solve for monthly principal & interest payment, home purchase price, down payment, mortgage rate, or loan term.
Compute Net Present Value (NPV), required future cash inflow, maximum initial capital outlay, or hurdle discount rate.
Solve for percentage Return on Investment (ROI), final exit value, or allowable initial cost basis.
Solve for gross margin percentage, required selling revenue, or allowable Cost of Goods Sold (COGS).
Solve for break-even sales volume in units, maximum fixed overhead, minimum unit selling price, or maximum variable cost.
Solve for Price-to-Earnings (P/E) valuation multiple, implied fair share price, or required Earnings Per Share (EPS).
Solve for annual dividend yield percentage, annual cash dividend per share, or implied share price.
Instantly convert between capital doubling time in years and annual compound return rate.
Solve for Bond Yield to Maturity (YTM), annual coupon payment, bond market price, par value, or years to maturity.
Solve for corporate Free Cash Flow (FCF), Operating Cash Flow (OCF), Capital Expenditures (CapEx), or Net Working Capital change.
Solve for liquidity Current Ratio, required Current Assets, or maximum allowable Current Liabilities.
Solve for Debt-to-Equity financial leverage ratio, total debt capacity, or required shareholders' equity.
Solve for SaaS CAC payback period in months, allowable Customer Acquisition Cost, required ARPA, or gross margin.
Solve for SaaS Lifetime Value to CAC ratio (LTV:CAC), maximum allowable monthly churn, target ARPA, or CAC ceiling.
Solve for David Sacks / Craft Ventures SaaS Burn Multiple, Net Cash Burned, or required Net New ARR.
Compute exact Fisher real purchasing-power return, required nominal return, or break-even inflation rate.
Solve the continuous compounding equation A = P × e^(rt) for final balance, principal, continuous rate, or time.
Solve the Gordon Growth Model PV = D₁ / (r - g) for intrinsic value, next-period cash flow, cost of equity, or terminal growth rate.
Solve the Capital Asset Pricing Model ER = Rf + β(Rm - Rf) for expected cost of equity, risk-free rate, asset beta, or market return.
Bidirectionally solve V = I × R for electrical potential difference (voltage), circuit current, or ohmic resistance.
Solve P = V × I for electrical power in Watts, circuit voltage in Volts, or current draw in Amperes.
Solve E_k = ½mv² for translational kinetic energy, moving mass, or required velocity.
Solve U = m × g × h for gravitational potential energy, object mass, gravitational acceleration, or elevation height.
Solve F = m × a for net force in Newtons, inertial mass in kilograms, or linear acceleration in m/s².
Solve F = G × m₁ × m₂ / r² for gravitational attraction force, celestial masses, or orbital separation distance.
Solve PV = nRT for absolute gas pressure, container volume, molar quantity, or absolute temperature in Kelvin.
Solve the universal wave equation v = f × λ for phase propagation velocity, wave frequency, or wavelength.
Solve for observed Doppler-shifted frequency, emitted source frequency, source velocity, or observer velocity.
Solve n₁ sin(θ₁) = n₂ sin(θ₂) for angle of refraction, angle of incidence, or refractive indices of optical media.
Solve F_c = m × v² / r for radial centripetal force, rotating mass, tangential velocity, or turn radius.
Solve Hooke's Law F = k × x for linear elastic restoring force, spring rate constant, or linear deflection.
Solve p = m × v for translational momentum in kg·m/s, object mass, or velocity.
Solve W = F × d × cos(θ) for mechanical work in Joules, applied force, displacement distance, or force angle.
Solve ΔL = α × L₀ × ΔT for thermal length change, coefficient of thermal expansion, initial length, or temperature delta.
Solve Q = (k × A × ΔT) / L for conductive heat transfer rate in Watts, thermal conductivity, surface area, temperature difference, or wall thickness.
Solve Einstein's Lorentz time dilation Δt = Δt₀ / √(1 - β²) for dilated observer time, proper rest time, or fraction of light speed β = v/c.
Solve v_e = √(2GM / R) for planetary escape speed, celestial body mass, or starting orbital radius.
Solve P = ε × σ × A × T⁴ for radiative thermal power, surface emissivity, radiating area, or absolute temperature in Kelvin.
Solve F = k_e × q₁ × q₂ / r² for electrostatic force between point charges, charge magnitudes in microcoulombs, or separation distance.
Solve E = h × f for photon energy in electron-volts (eV), electromagnetic wave frequency in THz, or Planck constant scaling.
Solve N(t) = N₀ × (0.5)^(t / t_½) for remaining quantity, initial sample quantity, elapsed time, or isotope half-life.
Solve Re = (ρ × v × D) / μ for dimensionless Reynolds number, fluid density, pipe velocity, hydraulic diameter, or dynamic viscosity.
Solve the incompressible continuity equation Q = A × v for volumetric flow rate, cross-sectional pipe area, or fluid velocity.
Solve h_f = f × (L / D) × (v² / 2g) for frictional head loss in meters, Darcy friction factor, pipe length, internal diameter, or flow velocity.
Solve ΔP = 0.5 × ρ × (v₂² - v₁²) for Venturi static pressure drop, fluid density, upstream velocity, or throat velocity.
Solve δ = (F × L³) / (3 × E × I) for maximum tip deflection, point load F, beam span L, Young's modulus E, or area moment of inertia I.
Solve σ = (F × L) / (4 × S) for peak midspan flexural bending stress, center point load, span length, or elastic section modulus.
Solve C = ε_r × ε₀ × A / d for capacitance in picofarads (pF), dielectric constant, plate overlap area, or dielectric separation.
Solve f_c = 1 / (2πRC) for -3 dB filter cutoff frequency, series resistance R, or filter capacitance C.
Solve X_L = 2πfL for AC inductive reactance in Ohms, operating frequency in Hertz, or inductance in millihenries.
Solve f₀ = 1 / (2π√(LC)) for natural LC resonant frequency, tank inductance L, or tuning capacitance C.
Solve V_s / V_p = N_s / N_p for secondary output voltage, primary input voltage, primary winding turns, or secondary winding turns.
Solve P = √3 × V_L × I_L × PF for three-phase real power in Watts/kW, line-to-line voltage, line current, or power factor.
Solve V_out = V_in × R₂ / (R₁ + R₂) for output tap voltage, supply voltage, top series resistor R₁, or bottom shunt resistor R₂.
Solve R = (V_s - V_f) / I_f for current-limiting resistor value, supply voltage, LED forward voltage drop, or forward current.
Solve η_max = (1 - T_C / T_H) × 100 for theoretical maximum thermal efficiency, hot reservoir temperature, or cold sink temperature in Kelvin.
Solve COP = Q_thermal / W_elec for refrigeration or heat-pump Coefficient of Performance, thermal cooling/heating capacity, or compressor electrical power.
Solve P_shaft = (ρ × g × Q × H) / η for pump shaft power, volumetric flow rate, total dynamic head, fluid density, or pump efficiency.
Solve T_out = T_in × (N_out / N_in) × η for output shaft torque, input motor torque, driven gear teeth, driver pinion teeth, or transmission efficiency.
Solve T = K × F × d for fastener installation torque, axial clamp preload force, nut factor K, or nominal bolt diameter.
Solve ΔL = (F × L₀) / (A × E) for axial elastic elongation, tensile/compressive load, original bar length, cross-sectional area, or Young's modulus.
Solve a² + b² = c² for the hypotenuse c or either orthogonal leg a or b of a right triangle.
Solve Δ = b² - 4ac for the quadratic discriminant Δ or any coefficient a, b, or c in ax² + bx + c = 0.
Solve A = (θ / 360) × π × r² for circular or sector area, radius r, or central angle θ (set θ = 360° for a full circle).
Solve V = (4/3) × π × (R³ - r³) for solid or hollow sphere volume, outer radius R, or inner cavity radius r (set r = 0 for a solid sphere).
Solve V = π × r² × h for right circular cylinder volume, cylinder radius r, or axial height/length h.
Solve V = (1/3) × π × r² × h for right circular cone volume, base radius r, or vertical apex height h.
Solve a_n = a₁ + (n - 1)d for the n-th term, first term a₁, term index n, or common difference d.
Solve a_n = a₁ × r^(n - 1) for the n-th geometric term, initial term a₁, common ratio r, or term index n.
Bidirectionally solve y = b^x ⇔ x = log_b(y) for the exponential result y, logarithm exponent x, or base b.
Solve c² = a² + b² - 2ab cos(C) for any triangle side c, a, b or the included angle C in degrees.
Solve a / sin(A) = b / sin(B) for side a, side b, opposite angle A, or opposite angle B.
Solve Heron's formula A = √(s(s-a)(s-b)(s-c)) for triangle area A or any side length a, b, or c.
Solve θ = ((n - 2) × 180) / n for the single interior vertex angle θ or the number of polygon sides n.
Solve d = √(Δx² + Δy²) for straight-line Euclidean distance d, horizontal coordinate delta Δx, or vertical coordinate delta Δy.
Solve the Golden Section S = a + b = φ × a for total span S, major segment a, or minor segment b.
Solve PE = ((E - T) / T) × 100 for signed percent error, experimental measured value E, or theoretical true value T.
Solve Euclidean division N = d × q + r for remainder r (N mod d), dividend N, divisor d, or integer quotient q.
Solve HM = 3 / (1/a + 1/b + 1/c) for the harmonic mean of three rates/multiples, or solve backwards for the required third value c.
Solve z = (x - μ) / σ for standard normal Z-score, raw observation x, population mean μ, or standard deviation σ.
Solve SE = s / √n for standard error of the sample mean, sample standard deviation s, or required sample size n.
Solve MOE = z × (σ / √n) for confidence interval half-width, critical Z-score, population standard deviation, or sample size n.
Solve Cochran's sample size formula n = z² × p(1 - p) / E² for required respondents n, margin of error E (%), critical z*, or baseline proportion p.
Solve CV (%) = (σ / μ) × 100 for relative standard deviation (CV), standard deviation σ, or sample mean μ.
Solve b₁ = r × (s_y / s_x) for ordinary least-squares regression slope b₁, Pearson correlation r, response standard deviation s_y, or predictor standard deviation s_x.
Solve OR = (p₁ / (1 - p₁)) / (p₂ / (1 - p₂)) for epidemiological Odds Ratio, treatment event probability p₁, or control event probability p₂.
Solve P(A|B) = (P(B|A) × P(A)) / P(B) for posterior probability, prior probability P(A), likelihood sensitivity P(B|A), or marginal evidence P(B).
Solve μ = λ × t for expected Poisson arrival count μ, arrival rate λ per unit time, or observation window t.
Solve μ = n × p for expected binomial successes μ, number of independent Bernoulli trials n, or single-trial success probability p.
Solve E[X] = k / p for the expected number of trials to achieve k successes (set k = 1 for the Geometric distribution), target successes k, or trial probability p.
Solve S = (R_p - R_f) / σ_p for annualized Sharpe Ratio, portfolio return R_p, risk-free rate R_f, or annualized portfolio volatility σ_p.
Solve t = (x̄ - μ₀) / (s / √n) for Student's t-statistic, sample mean x̄, null hypothesis mean μ₀, sample standard deviation s, or sample size n.
Solve d = (M₁ - M₂) / SD_pooled for Cohen's d standardized effect size, treatment mean M₁, control mean M₂, or pooled standard deviation.
Solve BMI = m / h² for Body Mass Index, body mass in kg/lb, or stature height in meters/cm/ft.
Solve the Mifflin-St Jeor equation BMR = 10m + 6.25h_cm - 5a + s for resting daily kilocalories, body mass, height, age, or sex offset.
Solve THR = ((HR_max - HR_rest) × I%) + HR_rest for target training heart rate, maximum heart rate, resting heart rate, or training zone intensity.
Solve d = v × t for race distance, average speed (m/s, km/h, mph), or finish time (seconds, minutes, hours).
Solve C = (D / MPG) × P_fuel for total trip fuel cost, trip distance, vehicle fuel economy, or fuel price per gallon/liter.
Solve C = (P_W / 1000) × h × d × rate for electricity bill cost, appliance power in Watts/kW, daily run hours, billing days, or kWh tariff rate.
Solve T = (C_Ah × V × η) / P_load for backup battery runtime in hours, battery capacity in Amp-hours (Ah), nominal bank voltage, usable depth-of-discharge efficiency, or load wattage.
Solve W₁ / H₁ = W₂ / H₂ for scaled target width W₂, target height H₂, or source aspect ratio dimensions W₁ and H₁.
Solve PPI = √(W_px² + H_px²) / D_in for Pixels Per Inch (PPI), diagonal screen size in inches, horizontal pixel resolution, or vertical pixel resolution.
Solve G = (A × coats) / S_cov for total paint volume required, paintable wall area, number of coats, or manufacturer spread rate.
Solve V = L × W × T for concrete slab pour volume (m³, yd³, ft³), slab length L, slab width W, or slab thickness T.
Solve R = √(run² + rise²) for common rafter length R, horizontal roof run, or vertical ridge rise.
Solve PP = (B × (1 + tip / 100)) / N for per-person total share, pre-tip check subtotal B, gratuity percentage, or party size N.
Solve Q_new = Q_orig × (S_new / S_orig) for scaled ingredient weight/volume, original recipe amount, target servings yield, or original recipe yield.
Solve the APEX photographic exposure equation EV_ISO = log₂((N² / t) × (ISO / 100)) for Exposure Value, f-stop N, shutter time t, or sensor ISO.
Solve T = (S_GB × 8000) / B_Mbps for file transfer duration, file size in Gigabytes (GB), or network throughput in Megabits per second (Mbps).