Free Online Tools

Calculate relative humidity, dew point, wet-bulb temperature, vapor pressure, absolute humidity, and mixing ratio from dry-bulb readings. Free, browser-based.

Calculate air density from temperature, pressure, and humidity, or from altitude. Shows kg/m³, virtual temperature, speed of sound, and comparison to sea-level standard. Free, browser-based.

Calculate rock bulk density from mass and volume, rectangular blocks, or drill cores. Porosity from grain density. Compare to typical granite, basalt, limestone, and more. Free, browser-based.

Estimate your annual carbon footprint from car travel, flights, home electricity, and natural gas. Compare to global averages with regional grid factors. Free, browser-based.

Calculate rainfall volume from catchment area and depth, estimate storm runoff with a runoff coefficient, or compute rainfall intensity (mm/hr). Metric and imperial units. Free, instant, browser-based.

Calculate volumetric flow rate Q = A × v for pipes and open channels, estimate flow with Manning's equation, or convert between L/s, GPM, CFS, and m³/s. Metric and imperial units. Free, instant, browser-based.

Calculate river discharge Q from channel width, depth, and mean velocity (velocity–area method), trapezoidal cross-sections with bank slope, or Manning's equation. Results in m³/s, L/s, and CFS with river size classification. Free, browser-based.

Analyze temperature and precipitation climate data. Paste daily or monthly values to get mean, min, max, std dev, heating/cooling degree days, wet days, dry spells, and Northern Hemisphere seasonal summaries (DJF, MAM, JJA, SON). Free, browser-based.

Calculate cement, sand, aggregate, and water quantities for concrete mixes. Design by volume, cement bags, or grade presets (M10–M25). Enter mix ratio 1:S:A and water–cement ratio. Metric (m³, kg) and imperial (yd³, lb) units. Free, browser-based.

Calculate steel weight for round bar, rebar, square bar, flat bar, plate, and pipe. Enter dimensions and quantity — get total kg or lb, weight per meter, and volume. Carbon steel density 7850 kg/m³. Metric and imperial units. Free, browser-based.

Calculate pipe flow rate, velocity, friction head loss, and pressure drop. Modes: Q = Av, velocity from flow, Darcy–Weisbach, and Hazen–Williams for water pipes. Reynolds number and flow regime. PVC, steel, and cast iron C presets. Metric and imperial units. Free, browser-based.

Calculate pump hydraulic power, shaft power, and motor sizing from flow rate and head. Modes: hydraulic power (ρgQH), brake power with pump efficiency, motor input with motor efficiency, and power from pressure rise. Results in kW, hp, and W. Water and custom specific gravity. Metric and imperial units. Free, browser-based.