Free Solar Water Pump Sizing Calculator | Calculate TDH, Flow Rate & PV Array Size | Cylome
Free online solar pump sizing calculator — calculate Total Dynamic Head (TDH), daily water demand, and PV array watts for off-grid irrigation, livestock watering, and borehole systems. Supports 50+ countries: Kenya, Tanzania, Nigeria, South Africa, Ethiopia, India, Pakistan, Brazil, Mexico, USA, Australia and more. Enter borehole depth, pipe length, farm area, or livestock count. Get instant pump recommendations backed by real manufacturer H-Q performance curves — no signup required.
📖 How to Use This Calculator
Choose your mode below, then follow the steps in order.
Choose your application
Select Irrigation for crop watering or Livestock Watering for animal hydration systems.
Enter your farm details
For irrigation: enter total farm area (acres) and crop type. For livestock: select animal type and number of animals. Daily water demand is auto-estimated.
Set your location
Select your country/region — Peak Sun Hours (PSH) and daily evaporation rate (ET₀) are auto-filled based on your location.
Describe your water source
Enter water depth, how far it drops while pumping (drawdown), height to your field (discharge height), and total pipe length from source to field.
Choose power source
Solar ☀️ for off-grid, Grid ⚡ for mains, Generator ⛽ for diesel, Battery 🔋 for battery/inverter systems.
Get results instantly
Results update automatically as you fill in values. You'll see daily water need, flow rate, total head, recommended pump, and solar panel count.
Total area to be irrigated, in acres (1 acre = 4,047 m²).
Crop water need varies widely — vegetables need most, sorghum/maize need less.
Estimated daily water need: 20.9 m³/day (for 1 acres of veg)
Select the closest region — solar hours and evaporation rate are auto-filled.
Average daily solar irradiance hours. Higher PSH = more solar energy available.
How much water crops lose per day via evaporation and transpiration.
How the Solar Pump Calculator Works
Our solar pump sizing tool follows a four-step engineering workflow: estimate daily water demand → compute TDH using the Hazen-Williams friction formula → match your operating point against stored pump H-Q curves → size the PV array by dividing shaft power by Peak Sun Hours with derating.
Irrigation Sizing
Calculate daily water demand for drip or sprinkler irrigation based on crop type, area, and climate zone.
Livestock Watering
Determine pump flow and head requirements for cattle, goat, sheep, and poultry watering systems.
Direct Pump Selection
Enter flow rate (Q) and Total Dynamic Head (TDH) directly to find matching pumps from our database.
Real Pump Curves
Results are powered by manufacturer H-Q and η-Q performance curves — not rough estimates.
Key Engineering Formulas
Pump Shaft Power
Ppump = ρ × g × Q × H / η
Q = flow rate (m³/h), H = Total Dynamic Head (m), η = pump efficiency (decimal)
Friction Loss — Hazen-Williams
hf = 10.67 × L × Q1.852 / (C1.852 × D4.87)
L = pipe length (m), C = roughness coefficient, D = internal diameter (m)
Solar Array Sizing
Psolar = Ppump / (PSH × ηmotor × ηctrl × fderate)
PSH = Peak Sun Hours, fderate covers temperature, dust, and wiring losses
Frequently Asked Questions
- How do I size a solar water pump for my borehole or well?
- To size a solar pump for a borehole, you need three key values: total dynamic head (TDH = static lift + friction loss + discharge elevation), your daily water demand in cubic meters, and the peak sun hours at your location. Enter your borehole depth, pipe length, and diameter into our calculator — it uses the Hazen-Williams formula to compute friction losses, then matches your operating point against real pump H-Q curves to recommend the right pump and solar panel array. Works for any country including Kenya, Tanzania, Nigeria, India, Brazil, and the USA.
- How is Total Dynamic Head (TDH) calculated for a solar pump?
- TDH = static lift + friction loss + discharge elevation. Static lift = well depth (SWL) + drawdown. Friction loss is calculated using the Hazen-Williams equation: hf = 10.67 × L × Q^1.852 / (C^1.852 × D^4.87), where L is pipe length (m), Q is flow rate (m³/h), C is pipe roughness coefficient, and D is internal diameter (mm). Our free calculator handles all of this automatically — just enter your borehole depth and pipe details.
- How many solar panels do I need for a water pump?
- Solar panels are sized by dividing the pump shaft power by (Peak Sun Hours × controller efficiency × 0.82 PV derating). For example, a 500W pump shaft in a region with 5 PSH needs approximately 132 panels of 400W: 500 / (5 × 0.93 × 0.82) = 132W. Our calculator gives you the exact number of panels and total PV watts needed for your specific location and system — whether in Kenya, Spain, Australia, or Brazil.
- Can this calculator size a solar pump for livestock watering?
- Yes. Select 'Livestock Watering' mode and enter your animal types (cattle, goats, sheep, camels, dairy cows, poultry) and their counts. The calculator multiplies each animal type by its daily water requirement (e.g., cattle: 50 L/day, goats: 5 L/day, dairy cows: 80 L/day) with a temperature factor, then computes the required flow rate, TDH, and solar panel size for your herd or flock. Covers all climate zones from arid (Sudan, Mali) to tropical (Nigeria, Indonesia).
- What pipe diameter should I use for a solar water pump?
- Pipe diameter affects both cost and friction loss — larger pipes reduce friction but cost more. As a rule of thumb, velocity in the pipe should stay between 1.0–2.5 m/s to balance cost against friction. Our pipe diameter suggestion tool recommends optimal diameters for your target flow rate, balancing energy efficiency with material cost. For flows above 10 m³/h, use at least 50mm (2 inch) diameter.
- Is this solar pump calculator free to use?
- Yes, 100% free with no registration required. You get instant results including daily water demand, flow rate, Total Dynamic Head (TDH), solar panel size (kW and number of panels), and specific pump model recommendations — all powered by real manufacturer performance curves, not estimates. Works in all countries worldwide.
- Which countries and regions does this calculator support?
- Our solar pump calculator covers 50+ countries across all continents: Africa (Kenya, Tanzania, Nigeria, South Africa, Ethiopia, Uganda, Sudan, Mali, Ghana, Senegal, Morocco, Egypt), South Asia (India, Pakistan, Bangladesh, Nepal), Southeast Asia (Vietnam, Thailand, Indonesia, Philippines, Myanmar), East Asia (China, Japan, South Korea), Central Asia (Uzbekistan, Kazakhstan, Afghanistan), Middle East (Saudi Arabia, UAE, Iran, Iraq, Jordan), Europe (Spain, Italy, Greece, Portugal, Turkey, Romania), Americas (USA, Mexico, Brazil, Peru, Colombia, Chile, Argentina), and Oceania (Australia, Papua New Guinea). Each location has pre-filled Peak Sun Hours (PSH) from the Global Solar Atlas.
- How does the solar pump calculator work for drip irrigation?
- Select 'Farming / Irrigation' mode, enter your total cultivated area in acres or hectares and crop type (vegetables, maize, beans, rice, sorghum, fruit, cassava, fodder, groundnut, or coffee), and the calculator estimates daily water demand using crop-specific Kc (crop coefficient) values and regional ET₀ (reference evapotranspiration). It then calculates the required flow rate and TDH, and recommends solar pumps suitable for drip irrigation systems — from smallholder farms in Kenya to commercial operations in Brazil or Australia.
- What is Peak Sun Hours (PSH) and how does it affect solar pump sizing?
- Peak Sun Hours (PSH) is the equivalent number of hours per day at peak solar irradiance (1 kW/m²). It represents the average daily solar energy available for PV production. Regions with higher PSH (e.g., Mali: 6.5, Chile Atacama: 7.0, Saudi Arabia: 6.5) need fewer solar panels than cooler regions (e.g., Japan: 4.0, Germany: 3.0). Our calculator pre-fills PSH from the Global Solar Atlas for your specific country and region, so you get accurate solar array sizing whether you are in Sub-Saharan Africa, South Asia, or Europe.
- Can I size a solar pump for mining or construction dewatering?
- Yes. Use 'Direct Pump Selection' mode and enter your target flow rate (m³/h) and Total Dynamic Head (m) directly. The calculator will match your operating point against Cylome's pump H-Q performance curves and recommend suitable models. Solar dewatering pumps for mining are popular in Chile (Atacama mining), Australia (outback mining), and South Africa (mining regions) where grid power is unreliable and solar irradiance is high.