Compute units

Every Solana transaction runs within a compute-unit limit. The priority fee is the limit times your price, so the limit you set is part of what you pay.

Compute use by transaction type

TransactionSourceUsedLimit +20 %

SOL transfersource codeSystem program, source1501,000

Compute-budget instructionsource codeeach, source1501,000

Token transfer (checked)source codep-token, SIMD-02662181,000

Measured rows: median and 90th percentile of computeUnitsConsumed over transactions of each program in the latest sampled blocks. Source rows: 150 CU for the System program and 150 CU per compute-budget instruction (agave); token transfers after the p-token upgrade (SIMD-0266): Transfer 186, TransferChecked 218 CU, against 4,645 and 6,200 before.

Limits

Maximum per transaction1,400,000 CU
Default per program instruction200,000 CU
Default per builtin instruction3,000 CU
Priority fee⌈limit × price ÷ 10⁶⌉ lamports
Unused unitsnot refunded

execution_budget.rs · compute_budget_limits.rs · SIMD-0170

Compute-unit limit

Price

µL / CU

import { ComputeBudgetProgram } from "@solana/web3.js";

tx.add(
  ComputeBudgetProgram.setComputeUnitLimit({ units: 200_000 }),
  ComputeBudgetProgram.setComputeUnitPrice({ microLamports: 10_000 }),
);
// priority fee: 2,000 lamports

FAQ

What is the maximum compute-unit limit on Solana?

1,400,000 compute units per transaction (MAX_COMPUTE_UNIT_LIMIT in the agave runtime).

What limit applies if I do not set one?

200,000 per program instruction and 3,000 per builtin instruction (SIMD-0170), capped at 1,400,000. With a priority price, the fee is charged on that default limit.

Are unused compute units refunded?

No. The priority fee is calculated from the limit you request, not from the units consumed. Setting the limit close to the real use is the cheapest way to pay a given price.

How do I find out how many units my transaction uses?

Simulate it (simulateTransaction returns unitsConsumed), or look up a past transaction: its metadata contains computeUnitsConsumed. Add a margin of 10–20 % for inputs that make the program work harder.

Simulate a transaction What did my transaction pay?Fee calculator