A naming note first: Keeper rebranded to Double in October 2025, and keeper.app now redirects to doublehq.com. Same product — and unrelated to Keeper Security, the password manager. Firms search "Karbon vs Double" as if the two are rivals, but they mostly do different jobs. Karbon runs the firm: client email, work, deadlines, and who owns what. Double runs the close: a two-way QuickBooks Online or Xero integration, AI bank feeds and reconciliation fixes, and review tools built around the client's ledger. There's real overlap — Double's entry plan also includes task management, a branded client portal and integrated email — but each product is organized around a different center: Karbon around the team's inbox, Double around the client's books. And they charge in exactly opposite ways.
By the ClientBrief Team · Last updated October 2026
If your bottleneck is coordinating people and email across the firm, Karbon is the tool. If your bottleneck is close quality on QuickBooks Online or Xero clients — miscategorized transactions, reconciliation gaps, chasing clients about bank lines — Double is. Pricing inverts: Karbon charges $59-89 per user per month (annual) with unlimited clients, while Double charges $10-50 per connected client per month with unlimited users. A five-person firm with 10 clients pays about $445/month on Karbon Business and $100-500 on Double; the same firm with 60 clients still pays $445 on Karbon but $600-3,000 on Double. Because the jobs differ, some bookkeeping firms run both — the real question is whether you need both.
Karbon and Double (formerly Keeper) pricing checked against each vendor's public pricing page.
Need documents from clients, not a full practice platform? ClientBrief does only that — $7.99/month flat, unlimited clients, no client login.
Start free — 14 days| Karbon | Double (formerly Keeper) | |
|---|---|---|
| Primary job | Practice management — shared email, work, deadlines, client records | Month-end close and automated file review on the client's ledger |
| Pricing basis | Per user, unlimited clients | Per connected client, unlimited users |
| Entry price | $59/user/month annual ($79 monthly, teams of 4+) — Team | $10/connected client/month — Core |
| Higher tiers | $89/user/month annual ($99 monthly, teams of 4+) — Business; Enterprise custom | $25 (Plus) and $50 (Scale) per connected client/month, mix-and-match per client; Enterprise contact sales |
| Ledger connection | Not a ledger tool — it manages the work around the books | Required — two-way QuickBooks Online or Xero integration, with AI bank feeds and reconciliation fixes on every tier |
| Triage — a shared team inbox where email becomes assigned work, on every plan | Integrated email on every tier; one practice email included, extra connected emails about $10/month each | |
| Client portal | Included on every plan; automatic client reminders on Business | Custom-branded client portal on every tier |
| Extra costs | eSignature credits sold separately, from $100 for 100 | Tax Suite needs a $200/month annual commitment; extra connected emails about $10/month each |
| Best fit | Firms of 3+ where email and handoffs are the bottleneck | Bookkeeping firms on QBO or Xero with fewer, larger clients and a growing team |
Pricing verified October 2026. The two models are inverse, so compare them against your own staff and client counts rather than headline rates. Karbon's entry tier understates what most firms pay — task automation and automatic client reminders sit on Business at $89/user/month — and its monthly rates are only offered to teams of four or more. Double's tiers are mix-and-match per client, so a light compliance client and a full advisory client don't have to cost the same, but every new ledger you connect adds to the bill.
Choose Karbon if the problem is the firm, not the books: client email lands in personal inboxes, nobody is sure who owns what, and deadlines slip between handoffs. Triage turns a shared mailbox into assigned, trackable work, and it covers every service line — tax, advisory, payroll — not just bookkeeping. Budget for Business at $89/user/month annual if you want automatic client reminders.
Choose Double if you run a bookkeeping practice on QuickBooks Online or Xero and the pain is close quality: miscategorized transactions, unreconciled accounts, and a month-end that depends on someone eyeballing every ledger. Unlimited users make it cheap to grow headcount — but count your clients first, because the bill rises with every ledger you connect.
If the work runs fine and the recurring frustration is clients not sending statements, receipts and tax documents, neither tool is the cheapest fix. ClientBrief does document collection — checklist out, uploads in, reminders automatic, no client login — for $7.99/month flat with unlimited clients, and runs alongside Karbon, Double, or both.
Where ClientBrief fits in: ClientBrief is a client document collection tool — $7.99/month flat, no per-user pricing, no seat minimums, unlimited clients. Send a checklist, clients upload without creating an account, reminders go out automatically. It's narrower than Karbon and Double (formerly Keeper) — it skips the wider practice-management and e-signature features either one offers — so firms often run it alongside whichever of the two they pick, just for the document-chasing part.
Is Keeper the same as Double?
Yes. Keeper rebranded to Double in October 2025, and keeper.app now redirects to doublehq.com. It's the same product — automated file review and month-end close for firms on QuickBooks Online or Xero. It has nothing to do with Keeper Security, the password manager.
Which is cheaper, Karbon or Double?
It depends on your ratio of clients to staff, and the answer genuinely flips. Karbon bills per user ($59-89/month annual), Double per connected client ($10-50/month). A five-person firm with 10 clients pays about $445/month on Karbon Business and $100-500 on Double. The same firm with 60 clients still pays $445 on Karbon but $600-3,000 on Double.
Can Double replace Karbon?
For a pure bookkeeping practice on QuickBooks Online or Xero, it can cover a lot: Double's Core plan includes task management, a branded client portal, integrated email and time tracking alongside the close. It's a weaker fit for work that isn't tied to a connected ledger — tax returns, advisory engagements, payroll — and it has nothing like Karbon's Triage for turning a shared inbox into assigned work. A mixed practice will usually still want a practice management tool.
Can Karbon replace Double?
No. Karbon tracks the work of closing the books — tasks, checklists, deadlines, who's on it — but it doesn't work inside the ledger. It won't categorize bank feeds or fix a reconciliation. Double's AI bank feeds, reconciliation fixes and review tools run on the connected ledger itself, and that's what its per-client price buys.
Which is better for a solo bookkeeper?
Count your clients. One Karbon seat costs $59-89/month however many clients you add, but its signature feature, Triage, coordinates work between people — less useful when you're the only one. Double for five QBO clients runs $50-250/month; for thirty clients it's $300-1,500. Since they do different jobs, pick the one that addresses your actual bottleneck.