INFORMATIONAL USE ONLY: ALWAYS TEST YOUR POOL WATER AND FOLLOW MANUFACTURER GUIDELINES.
Outdoor Calculation Engines

Pool & Yard Math

Precision calculators for pool chemistry, lawn fertilizer, seed coverage, and outdoor maintenance. Get the right amounts every time.

5+
Calculators
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Pool Chemistry
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Lawn & Garden
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Pool Chlorine Calculator

Calculate chlorine & shock treatment amounts

Chlorine Needed

To raise chlorine from to ppm

Shock Treatment
lbs

Cal-hypo shock (weekly maintenance)

Quick Reference

  • Free Chlorine1-3 ppm
  • pH Level7.2-7.6
  • Total Alkalinity80-120 ppm
  • CYA (Stabilizer)30-50 ppm
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Lawn Fertilizer Calculator

Calculate how much fertilizer your lawn needs

Example: 20-0-10

Nitrogen Needed
lbs

At 1 lb N per 1,000 sq ft

Fertilizer Needed
lbs

Based on % nitrogen

Bags to Buy
bags

lb bags

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Grass Seed Calculator

Calculate seed coverage for new lawns or overseeding

Seed Needed
lbs

At lbs per 1,000 sq ft for

Pro Tip

Buy 10% extra to account for edges and waste

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Mulch Calculator

Calculate mulch needed for flower beds and landscaping

Cubic Feet
cu ft
Cubic Yards
cu yd

For bulk delivery

2 Cu Ft Bags
bags

Standard bag size

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Pool pH Balancer

Calculate acid or soda ash to balance pH

To pH from to

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Safety Note

Add chemicals slowly and retest after 4 hours

Ideal Pool Chemistry Levels

Parameter Ideal Range Notes
Free Chlorine 1-3 ppm Keep above 1 ppm for sanitation
pH 7.2-7.6 Affects chlorine efficacy
Total Alkalinity 80-120 ppm Stabilizes pH levels
Cyanuric Acid (CYA) 30-50 ppm Protects chlorine from UV
Calcium Hardness 200-400 ppm Prevents plaster damage
Verification
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Based on APSP/ICC Standards
Pool & Spa Industry Guidelines
Last Updated: December 28, 2024
Sources & Guidelines
  • Association of Pool & Spa Professionals
  • University Extension Lawn Care Guides
  • EPA Water Treatment Standards