You can use these calculators to calculate depth of field.
A Flexible Depth of Field Calculator
A depth of field calculator is a useful photographic tool for assessing what camera settings are required to achieve a desired level of sharpness.
MSFA - Hyperfocal Distance
For landscape photographers Hyperfocal Distance is a useful tool for providing maximum depth of field.
Online Depth of Field Calculator
Calculate depth of field.
Optimizing Digital Photo Enlargment
The expected viewing distance of your print may change the requirements for a given depth of field and circle of confusion. Furthermore, an enlarged photo for use as a poster will require a larger sharpening radius than one intended for display on a website.
Using Tilt-Shift Lenses to Control Depth of Field
The calculator uses the lens focal length, lens tilt and untilted focusing distance to locate the plane of sharpest focus.