A film budget looks intimidating mostly because of the vocabulary, not the math. Once you know the standard categories, budgeting a short film or a feature is really just a matter of listing everything you'll need and pricing it against real local rates.
The "top sheet"
Most film budgets are organized as a top sheet: a one-page summary of major categories, each of which breaks down into detailed line items on separate pages. The top sheet is what a financier, producer, or line producer looks at first, so its categories are fairly standardized across the industry.
Above the Line (ATL)
Above the line covers the creative talent negotiated before the shoot even starts: story and underlying rights, producers, director, and principal cast. On a low-budget project this is often the most negotiable category, since many collaborators will defer part of their fee. On a studio production it can be the single largest line on the entire budget.
Below the Line: Production
This is the largest category on most budgets, everything needed to actually shoot: crew wages by department, day players and background talent, camera and lighting packages, sound, art department and set dressing, wardrobe and hair/makeup, location fees, transportation, and catering. Because it's driven by shoot days, this category is where the schedule you build directly determines your cost, fewer days and fewer location moves means a smaller production budget.
Below the Line: Post-Production
Editorial, sound mix, color grading, music (licensing or composition), visual effects, and final deliverables. It's easy to under-budget post because it happens after the pressure of the shoot has passed, but a rushed or underfunded post schedule shows up on screen just as much as a rushed shoot does.
Other / Administrative
Insurance, legal, accounting, and contingency. Contingency is a reserve, typically 10% of the subtotal, set aside for the unexpected: a location falling through, an extra shoot day, a piece of gear that breaks. Documentaries usually run a higher contingency, often 15%, since observational and access-dependent shoots are inherently less predictable than a fully scripted production.
How to actually estimate each line
For every line item, you need a quantity, a unit (flat fee, daily, or weekly), and a rate. The rate is where most first-time producers guess wrong, crew day rates, equipment rentals, and location fees vary enormously by city, and a number that's realistic in one market can be off by half in another. Where possible, price against real local rate data rather than a generic template, especially for crew and equipment, which are usually the two largest line items in the production category.
Once every line is filled in, the top sheet total is rarely the end of the conversation, it's the starting point for deciding what's actually affordable and what needs to be cut, deferred, or shot differently. Start with a blank film budget template if you want to build one by hand.