Solana Swap Costs: Rent, Priority Fees and 0.2s Slots

A Solana swap looks almost free: the network charges 5,000 lamports per signature, which is $0.00045 at SOL $89.72. The bill that matters is elsewhere. At 18:03:48 UTC on 7 November 2026, 100 SOL quoted 14.48791489 XMR — 0.14487915 XMR per SOL — while spot at 18:09 UTC was $89.72 for SOL and $609.75 for XMR. Three numbers explain the gap: a fixed deduction of about 0.0625 SOL, a direction spread of roughly 3%, and, if your payout is a token rather than native SOL, a refundable 1,488,440-lamport rent deposit. This article measures all three. (SOL to XMR guide)

The 5,000-lamport line is real, and it is small. I pulled three consecutive Solana blocks (466,606,318, 466,606,338, 466,606,345) with full transaction details. They held 287, 240 and 208 transactions. Median total fee: 5,001, 5,002 and 5,001.5 lamports. That is the 5,000-lamport base fee per signature plus a median priority tip of 1–2 lamports. Between 31.7% and 40.8% of transactions paid no priority fee at all; 93.3%–94.7% carried a single signature. The 90th percentile was 10,000–23,572 lamports ($0.0009–$0.0021), and the most expensive transaction in the sample paid 1,015,650 lamports — about $0.09. (SOL to XMR guide)

Priority fees are priced per compute unit, not per dollar. A transaction sets a compute-unit limit and a price in micro-lamports per CU; the fee is the product divided by one million. In those blocks the median consumed CU was 1,016–4,743, while the maximum was 393,842–431,508 — a swap or a token transfer sits in the hundreds of thousands. At 1,000 micro-lamports per CU, a 400,000-CU transaction pays 400 lamports ($0.000036). At 1,000,000 micro-lamports — one lamport per CU — it pays 400,000 lamports ($0.036). Paying more does not speed up a healthy network because block space is not scarce at 0.2-second slots; it only matters during a fee spike. For a single swap, the wallet default is usually correct. (how Monero fees work)

Rent is a deposit, not a fee. I asked the mainnet RPC (solana-core 4.4.0) for the rent-exempt minimum at six account sizes: 0 bytes → 650,240 lamports; 1 → 655,320; 82 → 1,066,800; 165 → 1,488,440; 200 → 1,666,240; 1,000 → 5,730,240. The points fit 650,240 + 5,080 × bytes exactly. A 165-byte SPL token account therefore needs 0.00148844 SOL ($0.134). Whoever creates the account pays it once; it stays inside the account and comes back when the account is closed. Closing costs a 5,000-lamport fee (plus any priority), so the round trip is about $0.0005. If you receive USDT-SOL or USDC-SOL regularly, keep the account; if it was a one-off, close it. (SOL to XMR guide)

The clock is faster than the folklore. Over slots 466,605,469 to 466,606,449 — 980 slots — block timestamps spanned 210 seconds: 0.214 seconds per slot. Four consecutive 200-slot segments each took 42–43 seconds. A separate 201-slot window (466,605,964–466,606,164) returned 201 blocks, so no slot was skipped. Whatever 400ms figure you remember, it does not describe this chain on 7 November 2026. Practically, inclusion can happen within a slot or two, and the wait you see at an exchange is policy, not physics.

The quote has a fixed deduction and a slope. Eight SOL→XMR quotes between 18:03:43 and 18:03:50 UTC fit out = 0.1450068 × (amount − 0.0625). At 0.5 SOL the quote was 0.06341459 XMR (87.5% retained); at 1 SOL, 0.13591765; at 10 SOL, 1.44103651; at 100 SOL, 14.48791489; at 1,000 SOL, 144.76687789. The minimum order was 0.15348228 SOL ($13.77) and the maximum 1,844.266512529 SOL ($165,468) — the cap is a dollar notional, not a coin count. At the minimum, 0.0625 SOL is 40.7% of the order: 0.15348228 SOL bought 0.01318933 XMR at 18:12:26 UTC, so 58.4% of the input value survived. Reverse quotes fit 6.6903 × (XMR − 0.00608): 10 XMR bought 66.86240877 SOL, with a minimum of 0.01943624 XMR and a maximum of 271.396857 XMR. (SOL to XMR guide)

The direction spread is the hidden line item. Using spot at 18:09 UTC (SOL $89.72, XMR $609.75, CoinGecko), the SOL→XMR slope of 0.1450068 implies $618.73 per XMR, 1.47% above spot. The reverse slope of 6.6903 implies $600.25, 1.56% below spot. Round trip therefore costs about 3.0% before any fixed deduction — the same order of magnitude as a platform fee, but expressed as a bid/ask band. On a 100 SOL order the quote delivered $8,834.0 of XMR against $8,972 of SOL: $138, or 1.54%, of which $5.6 was the fixed deduction and the rest the spread. (SOL to XMR guide)

Four mistakes cost more than the fee. First, network confusion: USDT exists on Solana, TRON and Ethereum; a deposit sent on the wrong chain is not recoverable by the receiving side. Second, swapping the entire balance: fees are paid in SOL, so leave at least 0.01 SOL. Third, treating the token-account rent as a loss: it is refundable, but only if you close the account. Fourth, assuming a 30-minute quote is a 30-minute chain wait: the chain moves in 0.2-second slots, and the window is a commercial promise, not a confirmation estimate. Check the asset id (sol-sol, usdt-sol) and the network line before sending. Remember that Solana is a transparent chain: the privacy comes from the XMR leg, not the SOL leg. (SOL to XMR guide)

The checklist and the numbers at writing time. Before a SOL swap: confirm the asset is native SOL (sol-sol) and not a wrapped or bridged version; keep 0.01 SOL for fees; expect a fixed deduction of about 0.0625 SOL on SOL→XMR; check the payout address on Solana; and close unused token accounts to reclaim 0.00148844 SOL each. As of writing (7 November 2026, 18:03–18:12 UTC), 100 SOL quoted 14.48791489 XMR, 1,000 SOL quoted 144.76687789 XMR, 10 XMR quoted 66.86240877 SOL, the order range was 0.15348228–1,844.266512529 SOL, and the catalog listed 437 assets on 65 networks, six of which need an extra ID. Quotes move; the live page governs. (SOL to XMR guide)