Pool Pump Size Calculator

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Determine the right pool pump size for your swimming pool. Enter the pool volume and desired turnover rate to calculate the required flow rate in gallons per minute (GPM). A properly sized pump keeps your pool water clean and circulated efficiently without wasting energy.

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Enter Your Measurements

Results

Recommended Pump Size

0.8

HP

Required Flow Rate

31.3

GPM

Max Flow (pipe limited)

31.3

GPM

Pipe Max Flow

43

GPM

Min Filter Size

2

sq ft

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Formula

Required GPM = Pool Volume ÷ (Turnover Hours × 60) | Pipe max flow limits effective GPM

How to Use This Calculator

How to Use

  1. 1

    Enter the pool volume in gallons (use the pool volume calculator if needed).

  2. 2

    Enter the desired turnover time (8 hours is standard, 6 for spas or heavy use).

  3. 3

    Enter the plumbing pipe diameter (1.5 inches for most residential pools).

  4. 4

    Select your filter type for minimum filter size recommendation.

Frequently Asked Questions

Frequently Asked Questions

How many hours should a pool pump run?

Run your pool pump long enough to turn over the entire pool volume at least once per day, typically 8 to 12 hours. In hot weather or with heavy use, run it longer. Variable speed pumps can run longer at lower speeds for better filtration and energy savings.

Is a bigger pool pump better?

No. An oversized pump wastes energy, creates excessive noise, and can damage the filter. The pump should be matched to the pool volume, pipe size, and filter capacity. Variable speed pumps are the most efficient option.
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About This Calculator

This calculator uses the formula: Required GPM = Pool Volume ÷ (Turnover Hours × 60) | Pipe max flow limits effective GPM. All calculations follow industry-standard methods. Results are estimates — always verify with a licensed professional for structural or code-compliant work.

Built and maintained by the CalcSmart team. Last updated March 2026.

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