The small-tools film: calculators, notes and the daily carry.
A calculation you can defend
Pump power at 250 m³/h and 38 m: hydraulic 25.89 kW, shaft 36.98 kW at 70% efficiency — with the formula printed under the result. Copy the result, or let the Assistant use it inside a report.
Formula printed with every result
Assumptions and defaults visible, editable
Copy as text, or use directly in AI-written documents
The result card: the values and the formula that made them.
Results, not just numbers
Suggested motor ratings, warnings when a value crosses a limit, gauges against thresholds — the calculators answer the next question, not just the arithmetic.
Limit checks colour the verdict
Favourites and recent calculators one click away
Units, converted properly
48 quantities and 268 units in eight engineering domains, from temperature and heads of water to K-factors, Kv and Cv, chiller efficiency and DN to NPS. Type “3 bar to psi” and it answers, with the formula and the value in every unit of the quantity.
A temperature and a temperature difference kept apart: a 10 K rise is 18 °F, never 50 °F
Slope six ways (%, ‰, mm/m, in/ft, 1 in N, degrees) and chiller efficiency as COP, EER or kW/TR
Typed as you think it: 68 °F in °C, DN 150 to NPS, 1:100 to %
The converter answering “3 bar to psi”, cropped: the formula, the note and the first rows of the value in every unit.
Every capability, declared
The complete list.
All forty, by discipline — with their main inputs.
Hydraulics · 8
Pump powerFlow (m³/h), Head (m), Efficiency (0-1), Density (kg/m³)
Pipe head loss (Hazen-Williams)Flow (m³/h), Diameter (mm), Length (m), C factor
Pipe size by velocityFlow (m³/h), Velocity limit (m/s)
Pump affinity lawsFlow at N₁ (m³/h), Head at N₁ (m), Power at N₁ (kW), Speed ratio N₂/N₁
Surge pressure (Joukowsky)ΔV (m/s), Wave speed (m/s), Density (kg/m³)
Booster pump headFloors served, Floor height (m), Residual head (m), Friction allowance (%)
Manning open-channel flowManning n, Hydraulic radius (m), Slope (m/m), Flow area (m²) — optional
Pipe thermal expansion & loopRun length (m), ΔT (°C), Material (steel/copper/ppr/cpvc), Pipe OD (mm)
HVAC · 15
Cooling load (area method)Area (m²), Density (W/m²)
Chilled water flowLoad (kW), ΔT (°C)
Condenser water flowCooling load (kW), Chiller COP, ΔT (°C)
Duct size (quick)Airflow (L/s), Velocity (m/s)
Duct dimensions (full ductulator)Airflow (L/s), Size by (friction / velocity), Friction rate (Pa/m), Velocity (m/s) — velocity method…
Psychrometrics — air state pointDry bulb (°C), RH (%) — or leave for WB/dew, Wet bulb (°C) — optional, Dew point (°C) — optional…
Air mixing (two streams)Stream 1 flow (L/s), Stream 1 DB (°C), Stream 1 RH (%), Stream 2 flow (L/s)…
Coil duty (total / sensible / latent)Airflow (L/s), Entering DB (°C), Entering RH (%), Leaving DB (°C)…
Insulation vs condensationPipe OD (mm), Fluid temp (°C), Ambient (°C), Ambient RH (%)…
Stair pressurization air (EN 12101-6)Closed doors on shaft, Leak area per closed door (m²), Other leakage (m²), Design pressure (Pa)…
LMTD / heat-exchanger dutyHot in (°C), Hot out (°C), Cold in (°C), Cold out (°C)…
Supply airflowSensible load (kW), ΔT (°C)
Outdoor air (ASHRAE 62.1)People, Area (m²), Rp (L/s·person), Ra (L/s·m²)…
Fan powerAirflow (L/s), Static pressure (Pa), Efficiency (0-1)
Expansion tank (closed loop)System volume (L), Fill temp (°C), Max temp (°C), Precharge (bar g)…
Electrical · 8
Building electrical loadArea (m²), Density (VA/m²), Diversity (0-1), Power factor
Lighting fixture countArea (m²), Target lux, Lumens per fixture, Utilisation factor…
Motor full-load currentMotor power (kW), Voltage (V), Power factor, Efficiency (0-1)…
Cable voltage dropCurrent (A), Route length (m), mV/A/m (from cable table), Line voltage (V)
Cable size (ampacity + VD)Design current (A), Route length (m), Line voltage (V), Max voltage drop (%)…
Transformer sizingDemand (kVA), Future allowance (%), Max loading (%)
Genset sizingDemand (kVA), Future allowance (%), Step-load margin (%)
UPS battery sizingLoad (kW), Runtime (min), Inverter efficiency, DC bus (V)…
Plumbing · 2
Water demand (Hunter curve)Total fixture units (WSFU), System (flush_tank / flush_valve)
Domestic hot water storageOccupants, Hot water (L/person·day), Peak-period fraction, Recovery time (h)…
Fire · 1
Sprinkler demand & storageDesign area (m²), Density (mm/min), Hose allowance (L/min), Duration (min)
Drainage · 1
Storm drainage (rational method)Runoff coefficient C, Rain intensity (mm/h), Catchment area (m²), Pipe slope (m/m)…
Process · 1
Detention / retention timeVolume (m³), Flow (m³/h)
Structural · 1
Tank flotation checkBase area (m²), Submerged height (m), Structure weight (kN), Anchorage (kN)
Vertical transport · 1
Lift traffic checkBuilding population, Car capacity (persons), Round-trip time (s), Number of cars…
Project controls · 1
Earned value (EVM)Planned value (PV), Earned value (EV), Actual cost (AC), Budget at completion (BAC)
Utilities · 1
Unit converter48 quantities, 268 units · typed as “3 bar to psi”
Against the field — calculations
40 verified calculators inside the project workspace
A folder of personal spreadsheets nobody dares audit
Formula and assumptions printed with the result
A cell with =0.746*B4/0.7 and a prayer
The Assistant uses the same calculators in written deliverables
Numbers retyped from Excel into Word, drifting
"The field" is the usual toolchain — the per-user construction cloud and the separate applications around it. Good tools; the difference here is one integrated record, on your own server.
Install it and begin — free for 14 days.
Nothing to request and nobody to wait for: download it, install it, and the 14-day evaluation starts by itself the first time it opens.