Try an aquarium calculator to determine how much substrate, gravel, or sand you need

https://aquarium-calculator-gallonsxvua200.novacrestiq.com/posts/what-is-fish-tank-liter-calculator-and-why-are-we-speakin-about-it

Attempt an aquarium calculator to determine how much substrate, gravel, or sand you need. Get handy estimates based upon depth and tank measurements.