Result
494 GPH
Look for sump pump capacity around 494 GPH at your required lift.
- Raw water load
- 411 gal/hr
- Lift factor
- 1.2 x
Estimate only. Check sizing, site conditions, product requirements, local rules, and qualified trade guidance before changing equipment or building materials. Read the full disclaimer.
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Quick answer
Quick answer
With the sample inputs, this calculator returns 494 GPH. Raw water load: 411 gal/hr. Use 494 GPH as a project starting point, then round to the way the material is sold and add an appropriate waste or repair buffer.
Publisher
Published by EverydayCalc Editorial
Our calculator pages are built to show the formula, explain the inputs, provide examples, and highlight assumptions so readers can understand how each result is estimated.
Results are estimates based on the inputs provided and the assumptions shown on this page. For financial, tax, legal, medical, or other high-stakes decisions, verify results with a qualified professional or official source.
How to use this calculator
One inch of rain over one square foot is about 0.623 gallons. The calculator applies runoff and lift factors to estimate pump capacity.
When to round up
Round up for long discharge lines, high vertical lift, heavy clay soil, or backup pump planning.
When to use this calculator
- Estimating materials before shopping
- Checking project coverage and waste
- Building a simple supply list
Tips for better estimates
- Measure twice and write down the units.
- Check product coverage and package sizes before shopping.
- Add waste for texture, touch-ups, pattern matching, and measurement error.
How this calculator is reviewed
This page is checked for inputs, formulas, examples, assumptions, topic fit, and related links. For this calculator, the review also covers measurements, coverage rates, waste allowance, package sizes, prep needs, and rounding rules.
The sample result is covered by automated tests, and the page links to supporting guides so readers can check the assumptions before acting. If a formula, label, or assumption looks off, send the page URL and your inputs through the contact page.
Formula and methodology
The calculator converts measurements and coverage assumptions into material quantity or project cost.
Result details: This page uses the inputs above to show raw water load and lift factor in the result area.
Assumptions to check
The key inputs are Drainage area, Rainfall rate, Runoff factor, Lift/friction factor. Check measurements, product coverage, material allowance, surface prep, product size, tools, and project-specific requirements.
Worked example
Example inputs: Drainage area: 1200 sq ft; Rainfall rate: 1 in/hr; Runoff factor: 0.55; Lift/friction factor: 1.2. With those values, the calculator returns 494 GPH. Look for sump pump capacity around 494 GPH at your required lift.
Project size to estimated materials
| Small room or repair | Measure carefully and buy one practical unit above the estimate |
|---|---|
| Medium project | Check product coverage and round up to full units |
| Large or irregular area | Add a project-specific buffer before buying |
| Patterned or irregular work | Use a larger waste factor before buying |
Example scenarios
- Use 494 GPH as the first material estimate, then compare it with product coverage and real project conditions.
- Add a project-specific buffer for measurement error, damaged material, odd layouts, or products that only sell in full units.
- Before buying, check whether prep supplies, fasteners, trim pieces, connectors, or tools are also needed.
Quick reference chart
| Sample result | 494 GPH |
|---|---|
| Raw water load | 411 gal/hr |
| Lift factor | 1.2 x |
| Best next step | Compare the result with the measurements, product coverage, full-unit sizes, site conditions, and project instructions before buying supplies. |
FAQs
Sump Pump Size Calculator questions
Can I use this as a final shopping list?
Use it as a planning estimate, then compare the result with your measurements, product coverage, site conditions, full-unit sizes, and project instructions.
Should I add a safety margin?
Usually yes. Add a buffer for measurement error, damaged material, layout changes, products sold in full units, and the extra material that fits this specific project.
What should I check before buying?
Check measurements, product coverage, package size, prep needs, compatible tools, fasteners, trim pieces, or other supplies the project requires.
Can this replace professional construction advice?
No. For structural, electrical, plumbing, roofing, or safety-critical work, confirm with a qualified professional.
Is the sump pump size calculator exact?
No. It is a project planning estimate. Compare it with your measurements, product coverage, site conditions, full-unit sizes, and project instructions.
What inputs matter most?
Drainage area, rainfall intensity, runoff factor, and lift factor matter most.
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Common planning mistakes
Skipping the right project buffer, measuring once, ignoring product limits, and forgetting the extra supplies or prep work that apply to this material.
Cite or embed this calculator
If this calculator helps a blog post, classroom resource, forum answer, seasonal guide, or local planning page, link to the canonical calculator URL so readers can run their own numbers and check the assumptions.
EverydayCalc.org, "Sump Pump Size Calculator", last updated July 9, 2026, https://everydaycalc.org/calculators/sump-pump-size-calculator/Was this calculator helpful?
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