pH Calculator
Calculate pH values for acids, bases, buffers, and biological systems with professional accuracy
pH Calculation
Molarity of the solution
Solution temperature for correction
Add any relevant notes about this calculation
pH Information
pH is a scale used to specify the acidity or basicity of aqueous solutions. It ranges from 0 (most acidic) to 14 (most basic).
pH Scale:
Common Applications:
Key Relationships:
• pH + pOH = 14 (at 25°C)
• pH = -log₁₀[H⁺]
• [H⁺] × [OH⁻] = 1×10⁻¹⁴
• Henderson-Hasselbalch: pH = pKa + log([A⁻]/[HA])
pH Application Scenarios
Reference guide for pH ranges across different biological, pharmaceutical, and industrial applications
Human Blood pH
Arterial blood pH regulation
Normal Range: pH 7.35 - 7.45
Critical Range: pH 7 - 7.8
Health Implications: pH < 7.35 (acidosis) or > 7.45 (alkalosis) can be life-threatening
Buffer Systems:
Applications:
• Clinical diagnostics
• Critical care monitoring
• Respiratory assessment
Gastric pH
Stomach acid pH levels
Normal Range: pH 1.5 - 3.5
Critical Range: pH 1 - 5
Health Implications: Essential for protein digestion and pathogen elimination
Buffer Systems:
Applications:
• Gastroenterology
• Drug absorption studies
• Antacid effectiveness
Urine pH
Urinary pH variation
Normal Range: pH 4.6 - 8
Critical Range: pH 4 - 9
Health Implications: Reflects metabolic status and kidney function
Buffer Systems:
Applications:
• Clinical analysis
• Kidney stone prevention
• Drug screening
Buffer Solutions
Pharmaceutical buffer preparation
Normal Range: pH 4 - 10
Critical Range: pH 2 - 12
Health Implications: Critical for drug stability and bioavailability
Buffer Systems:
Applications:
• Injectable formulations
• Oral solutions
• Stability testing
Drug Solubility
pH-dependent drug dissolution
Normal Range: pH 1 - 12
Critical Range: pH 0.5 - 13
Health Implications: Affects drug absorption and therapeutic efficacy
Buffer Systems:
Applications:
• Formulation development
• Bioequivalence studies
• Quality control
Cleaning Validation
Equipment cleaning pH monitoring
Normal Range: pH 2 - 12
Critical Range: pH 1 - 13
Health Implications: Ensures product safety and regulatory compliance
Buffer Systems:
Applications:
• Manufacturing equipment
• Validation protocols
• Residue analysis
Natural Waters
Surface and groundwater pH
Normal Range: pH 6.5 - 8.5
Critical Range: pH 4 - 10
Health Implications: Affects aquatic life and ecosystem health
Buffer Systems:
Applications:
• Water quality assessment
• Environmental compliance
• Ecosystem monitoring
Acid Rain
Atmospheric precipitation pH
Normal Range: pH 5 - 5.6
Critical Range: pH 3 - 7
Health Implications: Environmental damage to forests and aquatic systems
Buffer Systems:
Applications:
• Air quality monitoring
• Environmental impact assessment
• Pollution control
Soil pH
Agricultural soil acidity/alkalinity
Normal Range: pH 6 - 7.5
Critical Range: pH 3.5 - 9
Health Implications: Affects nutrient availability and crop productivity
Buffer Systems:
Applications:
• Agriculture
• Land management
• Remediation monitoring
Water Treatment
Drinking water pH adjustment
Normal Range: pH 6.5 - 8.5
Critical Range: pH 6 - 9
Health Implications: EPA secondary standard for aesthetic and corrosion control
Buffer Systems:
Applications:
• Municipal water treatment
• Corrosion control
• Disinfection optimization
Cooling Water
Industrial cooling system pH
Normal Range: pH 7 - 9
Critical Range: pH 6 - 10
Health Implications: Prevents corrosion and biological growth
Buffer Systems:
Applications:
• Power plants
• Manufacturing
• HVAC systems
Wastewater Treatment
Effluent pH control
Normal Range: pH 6 - 9
Critical Range: pH 5 - 10
Health Implications: Environmental discharge compliance
Buffer Systems:
Applications:
• Municipal treatment
• Industrial discharge
• Environmental protection
Food Safety
Pathogen growth inhibition
Normal Range: pH 3.5 - 6.5
Critical Range: pH 2 - 8
Health Implications: Critical for preventing foodborne illness
Buffer Systems:
Applications:
• Food preservation
• HACCP programs
• Shelf life extension
Beverage Production
Taste and stability optimization
Normal Range: pH 2.5 - 7
Critical Range: pH 2 - 8
Health Implications: Affects taste, color, and microbial stability
Buffer Systems:
Applications:
• Soft drinks
• Alcoholic beverages
• Fruit juices
Dairy Products
Milk and cheese pH monitoring
Normal Range: pH 6.4 - 6.8
Critical Range: pH 5 - 7.5
Health Implications: Quality indicator and safety parameter
Buffer Systems:
Applications:
• Quality control
• Process optimization
• Spoilage detection