Free deadline calculator to instantly calculate court dates and deadlines. A Form Interrogatory is the easiest tool to use for discovery.It's a set of questions on a standard form. Need to calculate a filing date? Our online filing date calculator is easy to use and can help you get the job done quickly. Calculate deadlines with ease with this free date calculator. Holidays and more are built in to ensure you don't have to count days manually. Practical Last Day to Serve Discovery (and be able to make a motion on it) – 90-100 days before trial. Deposition Notice – Defendant may serve any time. Filing Date and Deadline Calculator.