Reaction Rate Calculator
Calculate the rate of a reaction from concentration change over time.
About Reaction Rate Calculator
Dividing by the stoichiometric coefficient makes the rate identical whichever species is measured. The figure obtained is an average over the interval, not an instantaneous rate. Rates fall as reactants are consumed, so an average rate over a long interval understates the initial rate substantially.
Formula
Reaction Rate
Rate = −(1/a) × Δ[A] ÷ Δt for a reactant with coefficient a
- coefficient
- Divides the rate so all species give the same reaction rate
- Δ[A]
- Change in concentration over the interval
Worked example
With the default values below, Reaction Rate Calculator returns Reaction Rate of 0.00250000. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Initial concentrationminimum 0 mol/L
- 0.5 mol/L
- Final concentrationminimum 0 mol/L
- 0.2 mol/L
- Time elapsedminimum 0.001 s
- 120 s
- Stoichiometric coefficientaccepts 1–10
- 1
Results
- Reaction Rate
- 0.00250000 mol/L/s
- Change in Concentration
- 0.30000 mol/L
- Reaction Rate
- 0.150000 mol/L/min
- Conversion Achieved
- 60.000%
- Time to Full Conversion at This Rate
- 200.00 s
Step by step
- 1Values used
- 2Reaction Rate
- 3Reaction Rate= 0.00250000 mol/L/s
- 4Change in Concentration= 0.30000 mol/L
- 5Reaction Rate= 0.150000 mol/L/min
- 6Conversion Achieved= 60.000
- 7Time to Full Conversion at This Rate= 200.00 s
Assumptions and limits
- The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 8 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is Reaction Rate calculated?
Rate = −(1/a) × Δ[A] ÷ Δt for a reactant with coefficient a Dividing by the stoichiometric coefficient makes the rate identical whichever species is measured. The figure obtained is an average over the interval, not an instantaneous rate.
Why does Reaction Rate matter?
Rates fall as reactants are consumed, so an average rate over a long interval understates the initial rate substantially.
What values do I need to enter?
This calculator takes 4 inputs: Initial concentration, Final concentration, Time elapsed, Stoichiometric coefficient. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.