Legal · head to head
Spellbook vs Tabs3
Spellbook
Legal
Contract drafting and review assistant inside Microsoft Word
- From
- On request
- Rated
- -
Tabs3
Legal
Billing, trust and general ledger accounting for small and mid-sized US law firms
- From
- $69/month
- Rated
- -
The short version
- Each has a real cost: Spellbook it publishes no accuracy figure for its own output and no independent evaluation exists, so a firm must run its own assessment on real agreements.; Tabs3 the interface follows Windows desktop conventions from an earlier era, so new fee earners and staff take longer to train than they would on a browser-based competitor.
- They diverge on capability: Spellbook covers Word add-in drafting, Tabs3 covers Tabs3 Billing.
- Prices and features above were last checked on 31 August 2026.
Where they differ
Only the attributes on which Spellbook and Tabs3 actually diverge.
Identical on both: free tier (No), user rating (Not yet rated), category (Legal).
What each one covers
Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.
Only in Spellbook
- Word add-in drafting
- Contract review
- Benchmarks against market standards
- Question answering
- Named model providers
Only in Tabs3
- Tabs3 Billing
- Trust accounting
- General ledger and accounts payable
- PracticeMaster
- On-premises or cloud subscription
What people use each for
The jobs each tool is most often brought in to do.
Spellbook
- Transactional lawyers drafting commercial agreements in Wordnot Tabs3
- In-house teams reviewing inbound contracts without a contract lifecycle systemnot Tabs3
- Lawyers who want a first pass at redlines before applying their own judgementnot Tabs3
- Firms that need to know which model providers process their documents before adopting an AI toolnot Tabs3
Tabs3
- Small firms billing hourly that want billing and the firm general ledger in one system rather than reconciling twonot Spellbook
- Practices that must run three-way trust reconciliation without a separate bookkeeping packagenot Spellbook
- Firms that need an on-premises deployment because of client or insurer restrictions on cloud-hosted matter datanot Spellbook
- Long-established practices replacing a decades-old billing system while keeping accounting in housenot Spellbook
Where each one falls short
Documented limitations, not opinions. Every one is a constraint you would hit in normal use.
Spellbook
- It publishes no accuracy figure for its own output and no independent evaluation exists, so a firm must run its own assessment on real agreements.
- The ten times more accurate claim originated in a funding announcement as a statement of intent and has no methodology, dataset or baseline behind it.
- Contract text is processed by third-party model providers, so despite the zero data retention agreements this still needs checking against client confidentiality terms and outside counsel guidelines.
- Pricing is not published, so seat cost cannot be compared against competitors without booking a demo.
- It is a drafting assistant rather than a contract lifecycle system, so it does nothing for execution, obligation tracking or renewals.
Tabs3
- The interface follows Windows desktop conventions from an earlier era, so new fee earners and staff take longer to train than they would on a browser-based competitor.
- On-premises deployment puts backup, disaster recovery, server upgrades and patching on the firm, which small practices without IT support routinely underestimate.
- It is built around hourly and flat fee billing, so a contingency practice tracking case costs and settlement disbursements will find the case financial model a poor fit.
- PracticeMaster case management is priced separately from billing, so the advertised per-user rate is not what a firm wanting matter management actually pays.
- Choosing the on-premises option no longer avoids a subscription, because it is billed per user per month like the hosted version.
Pricing, plan by plan
Spellbook
On request- Spellbook$undefined/year
- Priced by the number of seats on the licence
- Rates quoted after a demo, not published
- Seven day free trial, free access for academic use
Tabs3
$69/month- OnSite Subscription$69/month
- Deployed on the firm server
- Billing, trust accounting and general ledger
- PracticeMaster add-on at 32 USD per user per month
- Tabs3 Cloud$89/month
- Hosted by the vendor
- Billing, trust accounting and general ledger
- PracticeMaster add-on at 35 USD per user per month
Which should you pick?
Choose Spellbook if
- You need word add-in drafting.
- You work on Windows, macOS, Web.
- You also want contract review.
Choose Tabs3 if
- You need tabs3 billing.
- You work on Windows, Web, iOS, Android.
- You also want trust accounting.
Questions people ask
- Is Spellbook or Tabs3 better?
- Neither clearly leads. Spellbook starts at On request and Tabs3 at $69/month, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
- Which is cheaper, Spellbook or Tabs3?
- Spellbook starts at On request and Tabs3 at $69/month.
- Does Spellbook or Tabs3 run on more platforms?
- Spellbook runs on Windows, macOS, Web. Tabs3 runs on Windows, Web, iOS, Android.
- What is Spellbook best used for?
- Spellbook is most often used for transactional lawyers drafting commercial agreements in word, in-house teams reviewing inbound contracts without a contract lifecycle system, lawyers who want a first pass at redlines before applying their own judgement, firms that need to know which model providers process their documents before adopting an ai tool. Of those, transactional lawyers drafting commercial agreements in word and in-house teams reviewing inbound contracts without a contract lifecycle system are not what Tabs3 is typically brought in for.
- What can Spellbook do that Tabs3 cannot?
- Spellbook covers Word add-in drafting, Contract review, Benchmarks against market standards, Question answering. Tabs3 covers Tabs3 Billing, Trust accounting, General ledger and accounts payable, PracticeMaster.
Answered from the vendors’ own pages
Spellbook: Is Spellbook's accuracy independently verified?
No. It publishes no accuracy figure of its own, and no third-party evaluation has been published. It did not participate in the Vals Legal AI Report, the main independent lawyer-baselined benchmark. Evaluate it on your own agreements during the trial.
Tabs3: Is Tabs3 right for a personal injury firm working on contingency?
No. It is built for hourly and flat fee billing with a firm general ledger. A contingency practice needs case cost tracking and settlement disbursement handling, which is what CASEpeer and Filevine are built around.
Spellbook: Which models does it use and where does our text go?
Spellbook names OpenAI GPT-5 and Anthropic Claude models, and states it has zero data retention agreements with both providers. Confirm the current terms and subprocessor list against your client confidentiality obligations before use.
Tabs3: Can I still buy Tabs3 as a perpetual licence?
No published perpetual price exists. The on-premises option, called OnSite Subscription, starts at 69 USD per user per month, with the hosted Tabs3 Cloud starting at 89 USD per user per month.
Spellbook: What does it cost?
Pricing is per seat but is not published. The vendor quotes it after a demo, so the seat rate cannot be compared with competitors in advance.
Tabs3: Does it replace QuickBooks?
For most firms yes. It includes a double-entry general ledger and accounts payable, which is the usual reason firms choose it over billing-only products.
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