The calculators below set the Registers for PIC Timers. The Register values will appear to the right of the settings. The 'Include in Source' checkboxes determine whether that Timer will be included in the sample application code shown below the calculators. The resolution of the slider controls might not be enough to get you the value you need especially with the larger ranges. Use the sliders to get close then enter values manually. I set each bit in the Registers individually to show the code better. Most people will probably want to convert it to a single value assignment to the register. This is designed for the 16F877A, but should work with other chips that have the same registers.