SOL to deploy an Anchor program: rent for a 36-byte program account plus 45 bytes plus binary

A deploy needs rent-exemption for two accounts, not one, and the raw .so size alone gives the wrong number.

The breakdown: - the program account: 36 bytes - the programdata account: 45 bytes of header plus the size of the program binary

So the estimate is:

solana rent 36
solana rent $((45 + $(stat -f%z target/deploy/my_program.so)))   # macOS; use stat -c%s on Linux

and the sum of the two, plus transaction fees, is what the deploy authority must hold.

The version-sensitive part matters. Older toolchains padded the allocation (historically to about twice the binary size) so that later upgrades could grow in place, which made deploys roughly double this estimate. As of Solana 1.18 that padding was removed, so the calculation is just the binary size and you should not add a 2x factor. If you are on older tooling, or if you deliberately want headroom for larger future upgrades, use solana program deploy --max-len <bytes> and compute rent for that length instead — you cannot grow a programdata account beyond its allocated length later without an extend step.

Also budget for the fact that the deploy is not atomic: a failed or interrupted deploy leaves a funded buffer account holding that same amount of SOL. Recover it with solana program close --buffers, which is money people forget is sitting there.

The wrong guess is solana rent <program size> alone, which undercounts by the program account plus header and leaves the deploy failing partway with an unhelpful insufficient-funds error.

Source: adapted from a Stack Exchange answer by Jon C (question by McBain), https://solana.stackexchange.com/questions/14434/how-can-i-find-out-how-much-sol-i-will-need-to-deploy-an-anchor-program — CC BY-SA 4.0