Created By : Rina Nayak

Reviewed By : Rajashekhar Valipishetty

Last Updated : Apr 03, 2023

Free Buffer Capacity Calculator is helpful to know how buffer will resist rapid change in pH. Give the amount of acid or base, initial pH, final pH values in the input fields of the tool and hit the calculate button to check the buffer capacity in a short span of an eye.

Amount of acid/base
Initial pH
Final pH
Buffer capacity

Steps to Calculate the Buffer Capacity

Check out the steps on how to find the solution buffer capacity. Follow these Principles to get the result easily.

  • Know the initial pH, final pH of the acids.
  • Otherwise, use Henderson–Hasselbalch equation to get the pH.
  • Get the change in pH by subtracting the final pH from the initial pH.
  • Divide the number of moles of an acid or base added per litre of the solution by the change in pH to obtain the buffer capacity value.

What is meant by Buffer Capacity?

Before learning about the buffer capacity, we need to know what is pH, how to find it and what buffer. pH is the amount of acidic/basic water is and we can compute the pH value of a chemical solution with the Henderson–Hasselbalch equation.

A buffer is a solution that has a combination of either a weak acid with its salt or a weak base with its salt, it is resistant to changes in pH. These are used to maintain a stable pH.

Buffer capacity means the quantity of the resistance of a buffer solution to changes in pH after adding H+ or OH- ions. The buffer capacity and initial pH affects the pH change after adding the acid base. More concentrated buffers will have a higher capacity because they have more molecules to interact with additional bases or acids. So, a higher concentration buffer has a slower changer in pH.

Buffer Capacity Formula

The buffer capacity value of a solution can be obtained by dividing the number of moles of the acid/base by the added per litre of buffer solution by change in pH.

Buffer capacity equation is β = n/ΔpH


β is the buffer capacity

n is the number of moles of an acid or base added per litre of the buffer solution

ΔpH is a change in pH

ΔpH = final pH - initial pH

Henderson–Hasselbalch equation is pH = pKa + log10([A-]/[HA])


[A-] is the concentration of a base in the buffer

[HA] is the concentration of the acid in the buffer

pKa is the dissociation constant on acid


Question: Find the ratio of concentrations of formate ion or formic acid in a buffer solution so that its pH is required to be 4? Identify the pH of this buffer to have the maximum buffer capacity? Ka of formic acid is 1.8 x 10-4.


Given that,

Ka of formic acid = 1.8 x 10-4

pH = pKa + log[Salt] / [Acid]

4 = -log(1.8 x 10-4) + log[formate]/[formic acid]

4 = 3.74 + log[formate]/[formic acid]

log[formate]/[formic acid] = 4 - 3.74

= 0.26

[formate]/[formic acid] = 1.8

The buffer capacity would be maximum near the pKa of the acid.

pH = pKa = -logKa

= -log(1.8 x 10-4)

= 3.74

Therefore, buffer capacity is 3.74

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Frequently Asked Question's on Buffer Capacity Calculator

1. Define buffer capacity?

Buffer capacity is the ability of a solution to resist the changes in PH. The solution can absorb or emit H+ or OH- ions.

2. What are the types of buffer solutions?

The two different types of buffer solutions are acidic buffers, alkaline buffers.

3. How to calculate buffer capacity?

Find the initial pH and final pH using the Henderson-Hasselbalch equation. Subtract final pH from the initial pH value. Divide the number of moles of an acid or base added to the buffer solution by the change in pH to get the buffer capacity.

4. What is the good buffer capacity value?

Buffer capacity ranges from 0.01 to 0.1 are used for several pharmaceutical solutions. So, it is a good buffer capacity.

Buffer Capacity Calculator