Calculate your garden sprinkler's exact coverage area, overlap zones, precipitation rate in mm/hour, how long to run your sprinkler to achieve your target watering depth, and the water cost per session — all calibrated for UK conditions.
Select your sprinkler type, enter your dimensions and settings — get coverage area, mm/hour precipitation rate, run time, overlap zones and weekly water cost.
Sprinkler type · spray pattern · lawn area → coverage, mm/hr, run time, heads needed, water cost
Calculate the optimal spacing and overlap for multiple sprinkler heads covering your lawn area uniformly. Head-to-head spacing (each head reaches the next) is the gold standard for uniform coverage.
Plan your complete weekly irrigation schedule based on UK seasonal evapotranspiration rates, your soil type and precipitation rate. Outputs a 7-day watering schedule.
Calculate the exact water meter cost of running your sprinkler system — per session, per month, and per season. Based on real UK water company tariffs.
Quick-reference guide to all common UK garden sprinkler types — typical coverage areas, flow rates, precipitation rates and best applications.
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| Sprinkler Type | Throw Radius | Typical Coverage | Flow Rate | Precip. Rate | Pattern | Best Use | UK Cost |
|---|---|---|---|---|---|---|---|
| Oscillating Most Popular | Up to 12m throw | 20–320m² | 400–900 L/hr | 8–14mm/hr | Rectangular fan | Rectangular lawns up to 320m² | £10–£50 |
| Impulse / Impact Wide Range | 3–20m radius | 28–1,250m² | 200–2,000 L/hr | 5–10mm/hr | Full/part circle | Large lawns, irregular shapes, strong throw | £15–£80 |
| Rotary (spinning arms) Value | 3–10m radius | 28–300m² | 150–700 L/hr | 6–10mm/hr | Full circle | Small-medium circular/square lawns | £8–£30 |
| Pop-Up Rotor Best Quality | 2–12m radius | 12–450m² | 60–600 L/hr | 10–22mm/hr | Full/part circle | Permanent systems — multi-zone | £5–£20/head |
| Pop-Up Spray Head Fixed | 1–5m radius | 3–80m² | 40–200 L/hr | 20–45mm/hr | Fixed arc patterns | Borders, narrow strips, small lawns | £3–£12/head |
| Travelling Sprinkler Novelty | 5–8m each side | Up to 2,000m² total path | 600–1,200 L/hr | 8–12mm/hr | Follows hose path | Very large lawns where hose can be laid | £40–£120 |
| Microspray / Mist Specialist | 0.5–2m radius | 0.8–12m² | 10–80 L/hr | 25–60mm/hr | Full circle fine mist | Seedbeds, new turf, greenhouse irrigation | £2–£10/head |
How much water your UK lawn actually needs at different times of year — and how to calculate run time from your sprinkler's mm/hr precipitation rate.
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| Month | ET Rate/Day | mm/Week (lawn) | At 6mm/hr | At 8mm/hr | At 10mm/hr | At 15mm/hr | Soil Type Note |
|---|---|---|---|---|---|---|---|
| March | 1.5mm/day | 10.5mm | 105 min | 79 min | 63 min | 42 min | Water rarely — rain usually adequate |
| April | 2.5mm/day | 17.5mm | 175 min | 131 min | 105 min | 70 min | Start irrigation on sandy soils |
| May | 3.5mm/day | 24.5mm | 245 min | 184 min | 147 min | 98 min | Irrigation often needed in dry spells |
| June Peak | 4.5mm/day | 31.5mm | 315 min | 236 min | 189 min | 126 min | Irrigate 2–3× per week on loam |
| July Peak | 5.0mm/day | 35mm | 350 min | 263 min | 210 min | 140 min | Daily irrigation on sandy soil |
| August | 4.0mm/day | 28mm | 280 min | 210 min | 168 min | 112 min | Hosepipe ban risk — use efficiently |
| September | 2.0mm/day | 14mm | 140 min | 105 min | 84 min | 56 min | Reduce irrigation — rain usually returns |
| October | 1.0mm/day | 7mm | 70 min | 53 min | 42 min | 28 min | Stop irrigation except new turf |
Minutes shown are total weekly run time to be divided across your chosen number of sessions. Subtract any rainfall received. ET rates from BIGGA UK irrigation guidance and typical UK weather data.
Top-rated UK garden sprinklers by type — with actual tested coverage areas, flow rates and honest assessments for UK lawn conditions.
Maximise sprinkler efficiency and lawn health with these UK-specific irrigation tips.
The single most important sprinkler scheduling rule for UK lawns. Watering between 5am and 9am minimises evaporation loss (temperatures low, wind calm, humidity high), ensures grass blades dry fully during daylight reducing disease risk, and allows water to penetrate the soil before midday heat increases evaporation from the surface. UK lawns watered in the evening remain wet overnight — increasing the risk of fusarium patch and other fungal diseases, particularly in humid UK autumn weather. On smart controllers, always set the start time to 6:00am.
The most accurate way to measure your sprinkler's actual precipitation rate on your specific lawn is the catch cup (tuna can) test. Place 5–6 identical containers (jam jars, tuna tins or purpose-made catch cups) randomly across your lawn's sprinkler zone. Run the sprinkler for exactly 15 minutes, then measure the depth of water collected in each container with a ruler. Multiply the average by 4 to get mm per hour. If the measurements vary significantly between cups (more than 2mm), your distribution uniformity is poor and the sprinkler heads need repositioning or replacing. This 15-minute test is more accurate than any calculator and accounts for your actual water pressure, nozzle wear and head positioning.
The majority of UK garden soils are clay-based or compacted — particularly in new-build gardens where topsoil has been disturbed. Clay soils can only absorb water at approximately 6–8mm/hr before surface run-off occurs. If your sprinkler applies water at 10–15mm/hr on clay soil, water simply runs off the surface without penetrating to the root zone. The solution is cycle-and-soak irrigation: instead of one 25-minute session, run two 12-minute sessions with a 30-minute rest between them. This allows each application to infiltrate fully before the next begins, dramatically improving root-zone water penetration on UK clay and compacted soils.
Wind is the biggest efficiency enemy of UK sprinkler irrigation. A 15mph wind (common in the UK) can reduce the effective precipitation rate of an oscillating sprinkler by 30–40% through drift, while simultaneously depositing water far outside the intended coverage zone. In windy conditions, the water cost per mm applied more than doubles. The UK Met Office wind forecast is your irrigation scheduling guide — check it before each session. A useful rule: if you can feel the wind on your face, postpone irrigation. On very windy days, even the most efficient impact or rotor sprinklers are largely ineffective — manual watering with a watering can at soil level is more efficient in these conditions.
This is the most common mistake in UK multi-zone irrigation systems. If one zone uses rotary pop-up heads (5–8mm/hr) and another uses fixed spray heads (25–40mm/hr), running both for the same time dramatically overwatered the spray zone. When designing or upgrading a UK sprinkler system, always select heads with matched precipitation rates across zones. The Rain Bird and Hunter matched precipitation nozzle ranges are designed specifically for this — their different arc nozzles (90°, 180°, 360°) all deliver the same mm/hr regardless of arc angle, ensuring perfectly uniform watering across a mixed layout.
A basic wired rain sensor costs £10–£20 and will save significantly more than that over a single UK irrigation season by automatically shutting off your sprinkler system when rainfall occurs. The UK's highly unpredictable weather means that without a rain sensor, automatic irrigation systems frequently run during or immediately after rainfall — wasting thousands of litres per season. Smart irrigation controllers (Rachio, B-hyve, Gardena Smart) go further by integrating with local weather forecasts to predict when rain will occur and adjust schedules proactively — skipping sessions before forecast rainfall rather than just during it. For UK conditions where a 10mm rainstorm can arrive with 2 hours' notice, smart weather-based control is significantly more effective than a basic rain sensor alone.
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