Solve any equation forward or backward—click any variable to make it the target with automatic SI unit conversions.
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).