Mathematics · Differential Equations

Exponential Growth and Decay ODE Calculator

Solve y′=ky from an initial value and evaluate the solution at time t.

Runs locally
Your numbers

Inputs and results stay in this browser. Change one value at a time to explore the relationship.

Your inputCalculatedPassed forward in chains
y(t)164.872127
Exponential factor1.648721
Instantaneous rate y′(t)8.243606

Calculation steps

  1. Multiply rate and time: 0.05×10=0.5.
  2. Compute e^0.5=1.6487212707001282.
  3. y(10)=100×1.6487212707001282=164.87212707001282.

Understand Exponential growth ODE

One idea, three depths

Choose how deeply to explain Exponential growth ODE

Exponential growth ODE: Solve y′=ky from an initial value and evaluate the solution at time t.

Age 5Explain it to a 5-year-oldStart with a picture

Imagine using Exponential growth ODE to answer this question: solve y′=ky from an initial value and evaluate the solution at time t? Enter Initial value y₀, Rate constant k, Time t; the calculator shows y(t). For example: For y₀=100, k=0.05 and t=10, y≈164.87. The answer tells you y(t).

Age 15Explain it to a 15-year-oldConnect it to the formula

When the rate of change is proportional to the current amount, separating variables produces an exponential solution. The rule is y(t)=y₀eᵏᵗ. Its input values are Initial value y₀, Rate constant k, Time t, and the main result is y(t). For example: For y₀=100, k=0.05 and t=10, y≈164.87.

CollegeExplain it at college levelState the model precisely

This calculator evaluates the stated exponential growth ode relation over the valid real-number domain stated below. The implemented relation is y(t)=y₀eᵏᵗ, evaluated from Initial value y₀, Rate constant k, Time t to produce y(t). When the rate of change is proportional to the current amount, separating variables produces an exponential solution. k is a continuous rate; a 5% discrete period multiplier is a different model.

Inputs and valid domain

  • Initial value y₀ must be a finite real number.
  • Rate constant k must be a finite real number.
  • Time t must be a finite real number.

Important boundary: k is a continuous rate; a 5% discrete period multiplier is a different model.

The formula

y(t)=y₀eᵏᵗ

How the calculator works through it

It substitutes Initial value y₀, Rate constant k, Time t into the formula and exposes every numerical step above. The main output is y(t), accompanied by Exponential factor, Instantaneous rate y′(t).

Read the result correctly

The y(t) is the direct answer to “solve y′=ky from an initial value and evaluate the solution at time t.” Read it with the units shown beside the inputs; a sign, angle, percentage or rate changes what the number means.

A worked check

For y₀=100, k=0.05 and t=10, y≈164.87.

Where this model stops being reliable

k is a continuous rate; a 5% discrete period multiplier is a different model.

Learn it by changing one value

Begin with the worked example, then change one value while keeping the others fixed. Compare the new result and calculation steps to identify which part of the formula changed.

Dictionary terms behind this calculator

Before studying the codeWhat you should know firstUse the calculator immediately, or check the foundations before reading the implementation.

These foundations help you understand why Exponential growth ODE works. They never block the calculator, and “optional” means useful context rather than a hidden requirement.

Hard requirements

  • Reading formulas and substituting values

    Exponential growth ODE uses y(t)=y₀eᵏᵗ. You need to recognise what each side represents before substituting the stated inputs or rearranging the relationship.

    Review this foundation about 4 min

Strong support

Optional enrichment

  • Exponential solution behaviour

    Exponential behaviour helps you recognise common growth, decay and response patterns related to Exponential growth ODE.

    Review this foundation about 7 min
Learn the missing foundationsI already know these — show the code

Mathematics → algorithm → program

Implement this calculation in code

These are direct reference implementations of the calculator's principal relationship and first output. They run locally and include a small known-answer check where the language supports it.

Algorithm

  1. Read Initial value y₀, Rate constant k, Time t.
  2. Evaluate the principal relationship: y(t)=y₀eᵏᵗ.
  3. Return y(t) and check the domain conditions described above.
Python
            from math import *

def exponential_ode(a, r, x) -> float:
    return (a * exp((r * x)))

assert abs(exponential_ode(100, 0.05, 10) - 164.87212707001282) < 1e-6 * max(1.0, abs(164.87212707001282))
          
Current calculator valuesUpdates when you change an input above.
              
            
C
            #include <assert.h>
#include <math.h>

double exponential_ode(double a, double r, double x) {
    return (a * exp((r * x)));
}

int main(void) {
    const double expected = 164.87212707001282;
    const double actual = exponential_ode(100, 0.05, 10);
    assert(fabs(actual - expected) < 1e-6 * fmax(1.0, fabs(expected)));
}
          
Current calculator valuesUpdates when you change an input above.
              
            
C++
            #include <cassert>
#include <cmath>
#include <numbers>

double exponential_ode(double a, double r, double x) {
    return (a * std::exp((r * x)));
}

int main() {
    constexpr double expected = 164.87212707001282;
    const double actual = exponential_ode(100, 0.05, 10);
    assert(std::fabs(actual - expected) < 1e-6 * std::fmax(1.0, std::fabs(expected)));
}
          
Current calculator valuesUpdates when you change an input above.
              
            
Linux x86-64 assembly

x86-64 NASM · System V ABI · Linux · SSE2 with libm where required

            ; double exponential_ode(double a, double r, double x)
; Linux x86-64 NASM · System V ABI · first eight doubles in xmm0–xmm7
extern exp
global exponential_ode
section .text

exponential_ode:
    push rbp
    mov rbp, rsp
    sub rsp, 48
    movsd [rbp-8], xmm0
    movsd [rbp-16], xmm1
    movsd [rbp-24], xmm2
    movsd xmm0, [rbp-16]
    mulsd xmm0, [rbp-24]
    movsd [rbp-48], xmm0
    movsd xmm0, [rbp-48]
    call exp wrt ..plt
    movsd [rbp-40], xmm0
    movsd xmm0, [rbp-8]
    mulsd xmm0, [rbp-40]
    movsd [rbp-32], xmm0
    movsd xmm0, [rbp-32]
    leave
    ret
          
Current calculator valuesUpdates when you change an input above.
              
            
MATLAB
            function result = exponential_ode(a, r, x)
    result = (a * exp((r * x)));
end
          
Current calculator valuesUpdates when you change an input above.
              
            
Wolfram Language
            ClearAll[mwCalculate];
mwCalculate[a_, r_, x_] := (a * Exp[(r * x)]);
          
Current calculator valuesUpdates when you change an input above.
              
            

Continue in mathematical software

The downloaded file includes your current inputs and first calculated result. It is created locally.

Floating-point answers can differ slightly by language, compiler and processor. Compare within a suitable tolerance rather than assuming every decimal representation will be identical.

Supporting sourcesAcademic referencesPrimary standards, textbooks and complete citations

Standards, reading and academic references

Use the calculator as the worked interaction, then consult the primary standards and academic textbooks listed below. MW SysArc links to the original sources; the explanation on this page is original and does not reproduce them.

Calculus Volume 1

Read OpenStax Calculus: Derivatives and integration
Cite this book
APA 7
Strang, G., & Herman, E. (2016). Calculus volume 1. OpenStax. https://openstax.org/books/calculus-volume-1/pages/1-introduction
MLA 9
Strang, Gilbert, and Edwin Herman. Calculus Volume 1. OpenStax, 2016, https://openstax.org/books/calculus-volume-1/pages/1-introduction.
Chicago author-date
Strang, Gilbert, and Edwin Herman. 2016. Calculus Volume 1. Houston, TX: OpenStax. https://openstax.org/books/calculus-volume-1/pages/1-introduction.

OpenStax entries are free to read online. Follow the licence shown on each linked source before redistributing or adapting its content.

Reuse the page responsiblyCite this pageAPA, MLA, Chicago, Harvard, BibTeX and RIS

These formats cite this calculator page itself. They are separate from the academic references above, which support the mathematical method and terminology.

APA 7

MW SysArc. (2026, July 21). Exponential Growth and Decay ODE Calculator. MW SysArc Tools. https://math.mwsysarc.com/differential-equations/exponential-growth-decay

MLA 9

MW SysArc. “Exponential Growth and Decay ODE Calculator.” MW SysArc Tools, 21 July 2026, https://math.mwsysarc.com/differential-equations/exponential-growth-decay. Accessed 31 Aug. 2026.

Chicago 17

MW SysArc. “Exponential Growth and Decay ODE Calculator.” MW SysArc Tools. Published July 21, 2026. Accessed August 31, 2026. https://math.mwsysarc.com/differential-equations/exponential-growth-decay.

Harvard

MW SysArc (2026) ‘Exponential Growth and Decay ODE Calculator’, MW SysArc Tools. Published 21 July 2026. Available at: https://math.mwsysarc.com/differential-equations/exponential-growth-decay (Accessed: 31 August 2026).

BibTeX and RIS records

BibTeX

@misc{mwsysarc_exponential_ode_2026,
  author = {{MW SysArc}},
  title = {Exponential Growth and Decay ODE Calculator},
  howpublished = {MW SysArc Tools},
  year = {2026},
  url = {https://math.mwsysarc.com/differential-equations/exponential-growth-decay},
  note = {Published July 21, 2026; accessed August 31, 2026}
}

RIS

TY  - ELEC
AU  - MW SysArc
TI  - Exponential Growth and Decay ODE Calculator
T2  - MW SysArc Tools
PY  - 2026
DA  - 2026-07-21
Y2  - 2026-08-31
UR  - https://math.mwsysarc.com/differential-equations/exponential-growth-decay
N1  - Published July 21, 2026
ER  -

Clear answers

Frequently asked questions

What does the Exponential growth ODE do?

Solve y′=ky from an initial value and evaluate the solution at time t.

How does the Exponential growth ODE work?

The calculator applies y(t)=y₀eᵏᵗ. When the rate of change is proportional to the current amount, separating variables produces an exponential solution.

What can I learn from the Exponential growth ODE?

It connects the mathematical rule to your chosen numbers and shows each calculation step. Change one input at a time to see how the result responds.

Does MW SysArc receive or store what I enter?

No. The calculation runs locally in your browser. MW SysArc does not receive or store your calculation inputs.

How should I use the result?

Use the steps to understand the method, then verify important school or professional work using the notation and rounding rules required in your setting.

Last reviewed . Calculations tested .

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