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About Instarista

Instarista makes free calculators that help homeowners and DIYers buy the right amount of material for their projects.

Most home projects start with the same question: how much do I need? How many bags of concrete for this pad, how many tons of gravel for the driveway, how many bundles of shingles for the roof. The answer is simple math, but it's easy to get a unit wrong when you're standing in the store aisle.

Our calculators do that math for you and explain how they did it. Each one shows its formula, the standard figures it relies on (like bag yields and material weights), and tips for measuring accurately. We'd rather you understand the estimate than just trust a number.

How we build our calculators

• We use standard industry figures printed on product packaging and published by manufacturers and suppliers.
• We state our assumptions next to every result, so you can adjust for the exact product you buy.
• Every calculator works in feet and inches or metric, and runs entirely in your browser.
• We test each calculator against worked examples before publishing it.

A note on accuracy

Our results are planning estimates. Products differ, job sites differ, and local building codes vary. For structural work, or anything where a mistake is expensive, confirm quantities with your supplier or a qualified contractor.

Get in touch

Found a mistake, or want a calculator we don't have yet? We read every message. Contact us.