Direct debit lets you take money from your customer's bank account on a date you've told them about in advance, under an authority they've given their own bank once and can cancel at any time. Bacs clears each collection over three days, so you need a valid mandate, advance notice of every amount, and either your own Service User Number or a provider who lends you theirs.
In this article
One thing to know before you read anything else on this subject, including this page. The Bacs rulebook and the Service User's Guide are behind a login for registered service users, so almost every confident statement you'll find online about direct debit rules is a provider's account of a private document. Where the scheme itself publishes something, we've linked it. Where only providers say it, we've said so.
The short version
- Bacs describes the collection cycle as taking "less than three days from start to finish", running from input day to entry day.
- The mandate can only be lodged with your customer's bank by you, never by the customer.
- The Direct Debit Guarantee sets advance notice at "normally 10 working days" for any change of amount, date or frequency, "or as otherwise agreed".
- Your own Service User Number takes weeks to months and usually needs revenue and a bond behind it. A provider's SUN gets you collecting without either.
- 98.7% of direct debit requests are eventually collected and 97.0% clear on the first attempt (Adfin platform data).
What a direct debit is
The scheme's own definition is worth starting from, because everything else follows from it. A direct debit is "an instruction from a customer to their payment service provider authorising an organisation to collect varying amounts from their account, as long as the customer has been given advance notice of the collection amounts and dates".
Two features of that sentence decide how you'll use it. You can vary the amount, so a monthly fee that changes, a usage bill and an annual increase all work without going back to your customer for a new authority. And you can only collect once you've told them what's coming, so notice is a condition and not a courtesy.
That's what separates it from a standing order, where your customer instructs their bank to send a fixed amount and only they can change it. If your fees move, a standing order moves when your customer gets round to it. It also separates direct debit from a card on file. Cards expire, get replaced after a fraud scare, and carry a higher fee on larger amounts.
The three day Bacs cycle
Bacs describes the whole process as taking "less than three days from start to finish", and names the days input, processing and entry. On day one you submit the file. On day two the files "reach recipient banks for individual payment processing". On day three, payments "are simultaneously debited from the recipients' accounts and credited to your account".
Two practical details come from the same page. Input day has a window: files must be transmitted to Bacs between 07.00 and 22.30. And you can submit up to 30 days ahead of the payment date, with a recall possible after submission as long as your bank hears from you before its cut off.
The cycle has a consequence you'll notice in your accounts, and it catches people out constantly. Money collected against an invoice due on the 1st reaches you a few days later, by design, so a report that blends direct debit with everything else will show your best-paying customers as late. That gets a page of its own in this batch, on why direct debit payments look late when they aren't.
The mandate
The mandate, or Direct Debit Instruction, is the authority your customer gives their bank. The scheme is specific about the paperwork: "All DDIs must follow all of the wording and the order of the information in the downloadable files", and "the design of all Direct Debits must be approved in writing by your sponsoring payment service provider before they can be issued".
Two rules on the same page catch businesses out more often than the wording does. You have to make sure the DDI is correctly completed before it goes to your customer's bank, and that your customer hasn't added any amount or date restrictions to it. And DDIs "can only be lodged with the paying payment service provider by you and not directly by the customer", so a customer who says they've set it up at their end has done something other than give you a working mandate.
Paperless mandates, the kind you collect online or over the phone, run on two Bacs services. AUDDIS sends new instructions to the bank electronically instead of on paper, and the scheme states that anyone wanting paperless "must become AUDDIS compliant first". Our guide to mandates covers the wording rules, the paperless conditions and the full lifecycle, including what share of mandates never make it as far as the bank.
Advance notice
Advance notice is the condition attached to the whole arrangement. Before you collect, your customer needs to know the amount and the date, and if either changes you have to tell them again.
The period is set inside the Direct Debit Guarantee itself: "If there are any changes to the amount, date or frequency of your Direct Debit the organisation will notify you (normally 10 working days) in advance of your account being debited or as otherwise agreed". Note the two hedges the scheme puts in its own sentence. Ten working days is what normally applies, and a different period can be agreed with your customer. That agreement is how providers offering shorter notice operate.
The Guarantee also covers the case where your customer asks you to take a payment: "If you request the organisation to collect a payment, confirmation of the amount and date will be given to you at the time of the request."
In practice the notice is your invoice, as long as it names the collection date and the amount. Getting that habit right protects you later, because a disputed advance notice is one of the grounds a customer can use to claim their money back.
The Direct Debit Guarantee
Every bank and building society that accepts direct debits offers the Guarantee, and it's the reason customers accept the arrangement at all. The scheme's consumer site states the core promise plainly: "If an error is made in the payment of your Direct Debit, by the organisation or your bank or building society, you are entitled to a full and immediate refund of the amount paid from your bank or building society".
Read that from your side of the counter. Your customer's bank refunds them first and asks questions afterwards, and Pay.UK is explicit that "it's the bank that is responsible for refunding you in the event of a mistake, even if the original error was made by the organisation collecting the payment". The money then comes back out of your account through the indemnity claim process.
Two balancing points sit in the same text. A customer who receives a refund they weren't entitled to "must pay it back when the organisation asks you to". And a customer can cancel at any time by contacting their bank, with written confirmation sometimes required, so cancellations reach you as a message from the bank instead of a conversation with you.
You'll find a widely repeated claim that a Guarantee claim has to be made within 13 months. We couldn't find that figure in any scheme or provider source, and GoCardless states the opposite, that there's no time limit. Our guide to the Guarantee sets out what the text actually covers and what gets attributed to it without a source.
What you need in order to collect
There are two routes, and the choice usually decides your first three months.
The first is your own Service User Number, the six digit identifier issued to an organisation collecting by direct debit, sponsored by a bank. Providers are candid about what banks ask for. GoCardless publishes that "typically, banks will refuse your request unless you have revenues >£1m", that "for some banks this can be £10m", and that they'll "probably ask for personal guarantees and a bond of £50-500k". London & Zurich lists the contractual capacity to indemnify the sponsor bank against Guarantee refunds among its direct requirements.
How long it takes depends on who you ask, and the disagreement is the useful part. GoCardless puts the application at 4 to 12 weeks in one place and the full direct setup at 3 to 6 months in another. London & Zurich says approval takes 2 to 10 weeks. Three providers, three answers, and no public scheme timescale to settle it.
The second route is a provider or bureau holding the SUN and collecting on your behalf. London & Zurich describes a bureau as a third party that "takes charge of handling Direct Debit payments on your behalf" and which "sets up a SUN for each of its merchants but will own each of these SUNs itself". You give up having your own name on the mandate unless the provider offers branding, and you skip the revenue test, the bond and the wait.
One article here goes deeper into what a small business can do without its own SUN, including what it costs to put your own name on the direct debit anyway. If your question is only about time, see how long setting up direct debit actually takes, where the answer turns out to have little to do with the setup step.
What direct debit costs
Direct debit is usually the cheapest way to be paid at any size of invoice, because the fee is capped where card fees aren't.
| Cost | Adfin | GoCardless |
|---|---|---|
| Per successful collection | 1% + 20p, capped at £4 | Standard 1% + 20p, capped at £4 |
| Higher tiers | High value direct debit +0.15% on the amount above £2,000 | Advanced 1.25% + 20p (cap £5), Pro 1.4% + 20p (cap £5.60) |
| Your own name on the mandate | £36 a month (Adfin Custom) | Paid add-on |
| Failed collections and retries | No charge | Verify at publish |
| Monthly minimum | None | None |
The cap is the number to hold onto. On a £5,000 invoice, a capped direct debit costs you £4 and a card at 1.5% plus 20p costs £75.20. That gap is why practices with larger fees tend to move to bank debit first and worry about convenience second. Whether providers charge you when a collection fails varies more than the headline rate does, and there's an article in this set on exactly that.
When a collection fails
Most of what goes wrong arrives as a message from a bank instead of a complaint from your customer, and the first one tends to be disorienting.
Bacs runs three reporting services, defined in its glossary. ADDACS advises you of amendments to or cancellations of mandates. ARUDD returns payments the bank couldn't apply. AUDDIS handles the electronic setup and cancellation of instructions. Each message carries a reason code, and the code tells you whether you're looking at a closed account, a customer who cancelled, or a genuine dispute.
Bacs doesn't publish those code lists openly, so every list on the web is a vendor reproduction, and they disagree with each other on individual codes. The guide in this set on AUDDIS and ADDACS codes reports the agreement and the disagreement instead of pretending to a definitive table.
Failed collections are the routine case and they mostly clear. 98.7% of direct debit requests are eventually collected, 97.0% on the first attempt, and 60.1% of requests that suffered a failure are still recovered (Adfin platform data, measured on 269,518 direct debit collections first attempted between July 2024 and mid-July 2026). A retry a few days later handles more of them than any conversation will.
Indemnity claims are the serious case. Under the scheme rules a paying bank has to refund a payer where there's been an error under the Guarantee, and "depending upon the error the indemnity claim process may be used". Everything below the scheme's indemnity claims page, including the challenge process guide and the best practice material, is login-gated, so the published detail on how long you have to challenge comes from providers and doesn't agree. Our guide on handling an indemnity claim lays out what each of them says.
Direct debit against the other ways of getting paid
The comparison people usually make is about convenience, and the one that changes your cash position is about who initiates the payment.
With a card link, a bank transfer or an open banking payment, your customer decides when to act, and their on-time rate reflects that: 72.7% of Apple Pay payments arrive on or before the due date, 65.1% of card payments and 57.9% of bank transfers (Adfin platform data). With a mandate in place, the collection happens on the date you set unless something breaks, and direct debit is 83.4% of the payments Adfin collects on its own rails, counted by number of payments rather than value (Adfin platform data).
Direct debit also has real limits. It's poorly suited to a first sale to a stranger, because the mandate and the notice period both take time. It gives your customer a refund right that no other method matches. And it needs your billing to be accurate, since an error becomes an indemnity claim instead of a credit note.
The pragmatic answer for most businesses is both: direct debit for anything recurring or contracted, and an instant method as the fallback when a collection fails or a customer wants to settle early. Adfin falls back to card automatically when a direct debit fails, which keeps the invoice moving without a new conversation.
Common questions
How does direct debit work for a UK business? Your customer signs a mandate authorising you to collect from their account. You give advance notice of each amount and date, then submit collections to Bacs, which clears them over a three day cycle of input, processing and entry days. You need either your own Service User Number or a provider that holds one.
How long does a direct debit take to reach my account? Bacs describes the cycle as taking less than three days from start to finish, with the payment debited from your customer and credited to you on the third day. Bank holidays affect the processing calendar, so the elapsed time can be longer than three calendar days.
How much notice do I have to give before collecting? The Direct Debit Guarantee says a change to the amount, date or frequency is notified "normally 10 working days" in advance, "or as otherwise agreed". The agreed alternative is what allows providers to offer shorter notice periods.
Do I need my own Service User Number? No. A provider or bureau can collect under its own SUN on your behalf. Your own SUN needs bank sponsorship, and providers publish requirements including revenue over £1m and a bond, with quoted timescales ranging from 2 weeks to 6 months.
What does direct debit cost? Adfin charges 1% + 20p per successful collection, capped at £4, with 0.15% added on the amount above £2,000 and no charge for failures or retries. GoCardless publishes 1% + 20p capped at £4 on its standard plan, rising on its Advanced and Pro tiers, and its own high value uplift is 0.3% on the same basis.
Can a customer get a direct debit payment refunded? Yes. Under the Direct Debit Guarantee a payer is entitled to a full and immediate refund from their bank where an error has been made, and the bank refunds them whether the error was yours or its own. The money is then reclaimed from you through the indemnity claim process.
Sources
- Bacs — Direct Debit (accurate as of August 2026)
- Bacs — Direct Debit, getting started (accurate as of August 2026)
- Bacs — Direct Debit Instruction templates and logo (accurate as of August 2026)
- Bacs — glossary (accurate as of August 2026)
- Bacs — indemnity claims (accurate as of August 2026)
- Direct Debit — the Direct Debit Guarantee (accurate as of August 2026)
- Direct Debit — how to claim (accurate as of August 2026)
This article explains how direct debit works and is not legal or financial advice. Last updated August 2026.
