模型，瀑布模型和螺旋模型都用于软件开发。瀑布模型也称为经典或线性模型，因为它遵循顺序阶段，而螺旋模型不遵循顺序阶段，而是遵循进化方式。与螺旋模型相比，瀑布模型中的风险量更多，因为在每个阶段完成后都会识别和细化错误或风险。
这两个模型瀑布和螺旋模型之间存在一些差异，如下所示：
| S.NO. | Waterfall Model | Spiral Model |
|---|---|---|
| 1. | Waterfall model works in sequential method. | While spiral model works in evolutionary method. |
| 2. | In waterfall model errors or risks are identified and rectified after the completion of stages. | In spiral model errors or risks are identified and rectified earlier. |
| 3. | Waterfall model is adopted by customers. | While spiral model is adopted by developers. |
| 4. | Waterfall model is applicable for small project. | While Spiral model is used for large project. |
| 5. | In waterfall model requirements and early stage planning is necessary. | While in spiral model requirements and early stage planning is necessary if required. |
| 6. | Flexibility to change in waterfall model is Difficult. | Flexibility to change in spiral model is not Difficult. |
| 7. | There is high amount risk in waterfall model. | There is low amount risk in spiral model. |
| 8. | Waterfall model is comparatively inexpensive. | While cost of spiral model is very expensive. |