Johan Rasmusson Two short rate models with numerical swaption pricing procedures Abstract The short rate model by Hull & White (1994a) and the one where the interest rate is described by Cox, Ingersoll & Ross (1985) are introduced. Their closed form solutions for analytical swaption pricing are presented and calibration to a swaption is done. The one factor models are afterwards used to numerically replicate a number of swaption price surfaces. The pricing formula by Black (1976) will be used to acquire the market prices for the swaptions from a volatility surface. These market prices will be compared to the simulated prices replicated by the models. Given this comparison an analysis in the replicating ability will be made. A comparison in between the models will also be made and suggestions for a continuation of this work are presented.