1. Discrete vs. Continuous Compounding
For nominal rate $R$ compounded $m$ times per year over time $T$, terminal future value is $FV = PV \left( 1 + \frac{R}{m} \right)^{m T}$. Taking the limit as $m \to \infty$ yields continuous exponential growth:
$$FV = \lim_{m \to \infty} PV \left( 1 + \frac{R}{m} \right)^{m T} = PV \, e^{R T}$$The Effective Annual Rate (EAR) relationship is:
$$\text{EAR} = e^R - 1$$2. Continuous Cash Flow Streams
For a continuous cash flow rate $C(t)$ discounted at continuous rate $r$, the present value integral is:
$$PV = \int_0^T C(t) \, e^{-r t} dt$$If $C(t) = C$ is constant, analytical integration yields:
$$PV = \frac{C}{r} \left( 1 - e^{-r T} \right)$$3. Python Numerical Compounding Converter
import numpy as np
def convert_nominal_to_continuous(nominal_rate, m_frequencies=[1, 4, 12, 365]):
"""
Compare discrete compounding EAR with continuous exponential limit.
"""
results = {}
for m in m_frequencies:
ear = (1.0 + nominal_rate / m)**m - 1.0
results[f"Compounded {m}x/yr"] = round(ear * 100, 4)
results["Continuous Limit (e^R - 1)"] = round((np.exp(nominal_rate) - 1.0) * 100, 4)
return results
if __name__ == "__main__":
rates = convert_nominal_to_continuous(nominal_rate=0.08)
for freq, ear_pct in rates.items():
print(f"{freq}: {ear_pct}%")