Funding mechanics · 4 rails
Card, ACH, wire, stablecoin. Four ways to get dollars onto a platform, differing by a factor of ten in cost and by three days in speed. This page covers which to use at which amount, why California cards decline so often, what an ACH hold actually means, and the wire trick that almost nobody here uses.
Cheapest rail
ACH
Fastest rail
Card
Funding is the part of buying crypto that everybody skips and everybody then has trouble with. The purchase itself is a button. Getting dollars onto the platform in the first place is where cards get declined for no visible reason, where deposits vanish into review queues, where holds appear that nobody explained, and where people quietly pay several percent for a rail they did not need.
None of this is complicated once someone lays it out. There are four rails. They differ by roughly a factor of ten in cost and by up to three days in speed. Each one has one or two specific failure modes, and all of those failure modes are avoidable if you know about them in advance. That is this page.
One framing point before we start. Nothing here is about which exchange to pick — that is on the exchanges page — and nothing here helps if physical cash is what you hold, because no bank rail accepts notes. If that is your situation, the cash guide is the right page.
The four rails
A card purchase settles in seconds because the card network guarantees the funds. You pay for that guarantee: typically 2% to 4%, plus an exchange-rate spread on top if you are buying through a simple checkout rather than an order book. Daily ceilings are usually low, which makes cards unsuitable for anything substantial regardless of cost. Use a card when the purchase is small and the urgency is genuine.
ACH is the US bank-to-bank system behind direct deposit. Platforms almost never charge to use it, so your only cost is the trading fee. Settlement takes one to three business days, and because an ACH debit can be reversed during that window, platforms typically restrict withdrawing the resulting crypto until it clears — while often letting you trade immediately. For recurring purchases and anything you are holding long term, this is the correct rail and the decision is not close.
A wire is irreversible and settles the same business day if you beat your bank's cut-off. Your bank charges a flat fee, commonly $15 to $35, and the platform usually charges nothing. Because the fee is flat rather than a percentage, the wire gets cheaper in relative terms as the amount rises: on $50,000 a $25 fee is 0.05%. There is no daily card-style ceiling. Above roughly $20,000, this is the obvious choice and almost nobody uses it.
If you already hold dollar-pegged stablecoins somewhere, moving them onto a platform costs only the network fee and settles in minutes. This is genuinely the cheapest way to move value between venues. It is not a first-purchase route, because you need stablecoins to begin with, and getting those requires one of the three rails above.
Side by side
| Rail | Cost structure | On $2,000 | Speed | Ceiling | Verdict |
|---|---|---|---|---|---|
| Debit card | Roughly 2–4% plus spread | $40–$90 | Seconds to minutes | Low daily caps typical | Speed only. Use for small urgent buys. |
| ACH bank transfer | Usually free to fund; trading fee only | Under $10 | 1–3 business days | Moderate, rises with account age | The default for almost everyone. |
| Domestic wire | Flat bank fee, often $15–$35 | $20–$45 | Same business day before cut-off | Very high | Best above roughly $20,000. |
| Stablecoin transfer in | Network fee only | Cents to a few dollars | Minutes | Effectively none | Moving between platforms, not first purchases. |
Indicative ranges across major US platforms; card pricing in particular varies by platform and by whether you buy through a simple checkout or an order book. Wire fees are charged by your bank, not the exchange.
Troubleshooting
This is the single most common support question we receive, and in nearly every case the exchange is not the problem.
Card networks assign merchant category codes, and digital-asset merchants attract elevated fraud scrutiny. A first transaction to an unfamiliar crypto merchant from a California account is a textbook trigger. The block is automated and often silent on the exchange side.
Do thisCall the number on the back of your card, confirm the transaction is yours, and ask them to whitelist the merchant. Then retry once — repeated retries can harden the block.
Some banks and credit unions simply do not permit digital-asset merchant transactions. This is a standing decision, not a fraud flag, and no amount of calling will change it for your account.
Do thisUse ACH or a wire from the same institution — those rails are usually unaffected — or fund from a different card at another institution.
Card authorisation checks the billing address and cardholder name against what the exchange submits. A middle initial, an old address or a ZIP entered from memory will fail the check.
Do thisMake your exchange profile match your card statement exactly. Same legal name, same billing address, same ZIP.
Card funding limits are usually much lower than ACH or wire limits, and they are often per-day rather than per-transaction. Splitting a purchase into three attempts can trip both the ceiling and the fraud logic.
Do thisCheck the platform's card limit before you try. For anything above it, the rail is wrong — use ACH or a wire.
Most platforms reject prepaid and non-reloadable cards outright, because they cannot be reliably tied to a verified identity. The decline is by design and permanent.
Do thisUse a bank-issued debit card in your own name, or a bank rail.
California issuers increasingly require step-up authentication. If the verification window is blocked by a pop-up blocker, closed too early, or the SMS code arrives late, the authorisation silently fails.
Do thisRetry with pop-ups allowed, complete the step-up promptly, and do not switch apps mid-flow.
Rail deep-dive
ACH is the plumbing behind your direct deposit and your utility autopay. It is a batch system rather than a real-time one, which is why it takes days and why it costs nothing. For crypto funding this combination is close to ideal — you are not in a hurry, and free is a very good price.
The confusing part is the hold. An ACH debit can be reversed by the originating bank for several days after it settles, which creates an obvious problem for a platform selling an irreversible asset. Their solution is to let you trade against pending funds while restricting the withdrawal of the resulting crypto until the risk window closes. So you can buy immediately but cannot move the coins for a few days, which reads like something is wrong when in fact the system is behaving exactly as designed.
Two practical implications. First, if your plan is to buy and hold on the platform for a while, the hold costs you nothing and ACH is unambiguously the right rail. Second, if your plan is to withdraw to a hardware wallet the same week, fund by wire instead — wires are irreversible, so platforms generally release withdrawals much sooner.
The setup step is worth doing before you need it. Linking a bank account involves either an instant credential-based verification or a slower micro-deposit process that takes a couple of days. Do that now, while nothing is pending, and the cheap rail is permanently available to you. It is the same logic as the prep checklist on our speed guide.
Rail deep-dive
Here is the gap in how most people think about funding. They compare "instant and expensive" against "slow and free" and pick one. The wire sits in a third position — same business day and cheap at size — and gets overlooked because a flat $25 fee looks worse than free until you notice it does not scale with the amount.
On $2,000 a $25 wire fee is 1.25%, which is worse than ACH. On $50,000 it is 0.05%, which is better than essentially anything else available to a retail buyer, and it arrives today rather than Thursday. There is no daily ceiling of the kind card rails impose. For anyone in Los Angeles converting a property sale, an equity event, a residual payment or a business distribution into digital assets, this is the rail.
Three things determine whether it goes smoothly. The cut-off: your bank sets it, not the exchange, and in California the practical deadline is usually early afternoon Pacific on a business day — miss it and you have paid a wire fee for next-day service. The name match: send from an account in your own name matching your verified platform identity exactly, because a wire from a business entity, a trust or a spouse's account will be held for review. And the reference: include precisely the memo or account reference the platform specifies, since that is how they attribute an incoming wire to you.
Get those three right and the money is available to trade the same afternoon. Get the name wrong and you are looking at several days of correspondence while compliance resolves it — which is the single most common cause of the "my large deposit is stuck" question we receive. Above about $100,000, it is also worth reading our OTC guide before you place the order, because at that size the venue matters more than the funding rail.
Our position
Some platforms accept credit cards. We think funding a volatile asset with revolving credit is the one genuinely bad decision available on this page, and we are not going to present it as a trade-off.
The mechanical problem is that many issuers classify crypto purchases as cash advances. That means a separate, higher fee, a separate and higher APR, and no grace period — interest accrues from the transaction date rather than from your statement date. You have therefore bought an asset that can fall 40% using money that costs you more than 20% a year, with the interest clock already running.
The behavioral problem is worse than the mechanical one. Borrowing to buy an asset changes how you hold it. A 30% drawdown you can wait out becomes a 30% drawdown plus a minimum payment, and that combination is what turns a long-term position into a forced sale at the bottom. We have seen this happen to people who understood the market perfectly well and were simply on the wrong side of a payment schedule.
If the only way you can fund a purchase is with credit, the honest reading is that the purchase should be smaller or later. That is not a moral position, it is a risk one.
The short answer
If you read nothing else on this page, read this table.
| Purchase size | Use this rail | Why |
|---|---|---|
| Under $200 | Card, or an app you already have | The absolute dollar difference is small and friction is the real cost at this size. |
| $200–$2,000 | ACH, order book | Free funding plus a low trading fee. This is the standard answer. |
| $2,000–$20,000 | ACH if you can wait, wire if you cannot | Both are cheap. The wire buys you same-day settlement for a flat fee. |
| $20,000–$100,000 | Domestic wire | No percentage cost, no daily card ceiling, and same-day arrival. |
| Over $100,000 | Wire, and consider an OTC desk | Above this, slippage on a retail book usually exceeds every fee you were optimizing. |
Thresholds are guidance rather than rules — they shift with your bank's wire fee, the platform's fee tiers and how quickly you intend to withdraw. The direction of travel, from card to ACH to wire as the amount rises, holds in every case.
Questions we actually get
Most often your issuer blocked it, not the exchange. California card issuers routinely flag first-time crypto merchant transactions as potential fraud, and some banks and credit unions block crypto purchases as standing policy. The exchange usually shows only a generic failure, so it looks like their problem. Call the number on the back of your card, ask specifically whether digital-asset merchant transactions are permitted, and authorise the merchant if they are.
ACH, by a wide margin. Funding by ACH is typically free, so your only cost is the trading fee — often well under half a percent on an order book. A debit card purchase usually costs somewhere between 2% and 4% plus an exchange-rate spread. On a $2,000 purchase that is roughly $10 versus $40 to $90. The debit card buys you speed and nothing else.
One to three business days to clear, though many platforms let you trade against pending funds immediately while restricting withdrawal of the resulting crypto until settlement. That withdrawal hold is not a red flag — ACH is reversible for several days, so platforms manage that risk. If you plan to move coins to self-custody quickly, use a wire instead.
Some platforms accept them and we would still advise against it. Card issuers frequently treat crypto purchases as cash advances, which means a higher fee, a higher interest rate and no grace period — interest starting the same day. You are then holding a volatile asset financed by expensive revolving debt. If the position falls, the debt does not. This is the one funding decision on this page we would call a mistake rather than a trade-off.
Your bank sets the cut-off, not the exchange, and in California the practical deadline is usually early afternoon Pacific time on a business day. Beat it and the funds typically land the same day. Miss it and you are waiting until the next business day, which defeats the purpose of paying a wire fee. Ask your branch or check your online banking for the exact domestic wire cut-off before you rely on it.
Nearly always a name or reference mismatch. Send from an account in your own name matching your verified account exactly, and include the reference or memo the platform specifies. A wire arriving from a differently named account — a business entity, a spouse, a trust — will get held for review, and unpicking it takes days. This is compliance procedure under Bank Secrecy Act obligations rather than suspicion of you.
Next in this series
The full rail-by-rail decision framework this page feeds into.
Read the guide ExchangesWhich platforms support which funding rails, and how they score overall.
Read the guide SpeedEvery route timed, including why card funding wins on the clock.
Read the guide CashWhat to do instead if physical notes are what you hold.
Read the guide SpendingThe other side of cards — spending from a crypto balance in LA.
Read the guide TaxRecord your cost basis from the first funded purchase onwards.
Read the guide