Legal · head to head
Luminance vs Westlaw
Luminance
Legal
Machine learning contract analysis for review, negotiation and compliance
- From
- On request
- Rated
- -
Westlaw
Legal
Thomson Reuters legal research platform, priced per seat with tiers from Edge to Advantage and negotiated enterprise contracts above 10 attorneys
- From
- On request
- Rated
- -
The short version
- Each has a real cost: Luminance no independent evaluation of its accuracy has been published, and it did not take part in the Vals Legal AI Report, so buyers have only vendor-produced evidence to work from.; Westlaw firms of 11 or more attorneys, which is most firms actually spending serious money on Westlaw, get no published price at all and negotiate blind against a sales team that sees every prior deal.
- They diverge on capability: Luminance covers Anomaly detection, Westlaw covers Case law and statute database.
- Prices and features above were last checked on 1 September 2026.
Where they differ
Only the attributes on which Luminance and Westlaw actually diverge.
Identical on both: starting price (On request), pricing model (quote), 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 Luminance
- Anomaly detection
- Contract negotiation
- Due diligence review
- Multi-language analysis
- Document comparison
Only in Westlaw
- Case law and statute database
- KeyCite
- Practical Law
- CoCounsel Legal
- Litigation analytics
- West Key Number System
What people use each for
The jobs each tool is most often brought in to do.
Luminance
- In-house teams auditing a contract estate for a specific exposure such as change of controlnot Westlaw
- Procurement and compliance functions reviewing supplier agreements at scalenot Westlaw
- Transaction teams reviewing large contract populations against a deal deadlinenot Westlaw
- Negotiation teams applying a standard playbook consistently across many counterpartiesnot Westlaw
Westlaw
- A solo attorney or small firm wanting published, self-service pricing rather than a sales negotiationnot Luminance
- A firm evaluating whether Practical Law and secondary sources justify moving from Edge to Advantagenot Luminance
- A litigation team wanting KeyCite and litigation analytics in the same research platformnot Luminance
- A firm that previously used Casetext and needs to understand that it must now buy CoCounsel Legal inside Westlaw insteadnot Luminance
Where each one falls short
Documented limitations, not opinions. Every one is a constraint you would hit in normal use.
Luminance
- No independent evaluation of its accuracy has been published, and it did not take part in the Vals Legal AI Report, so buyers have only vendor-produced evidence to work from.
- The one named accuracy benchmark, ContractIQ Bench, was built, run and scored by Luminance on a dataset it has not released, against comparison models it does not name.
- Value scales with document volume, so an organisation reviewing tens rather than thousands of contracts will not recover the licence cost.
- Output still requires qualified review, so it reduces reading time rather than removing the lawyer, and staffing plans that assume otherwise fail.
- Pricing is not published, so cost per matter cannot be modelled until after a sales process and a proof of concept.
Westlaw
- Firms of 11 or more attorneys, which is most firms actually spending serious money on Westlaw, get no published price at all and negotiate blind against a sales team that sees every prior deal.
- Casetext no longer exists as an independent, cheaper self-serve product; anyone who liked its pricing and simplicity now has to buy into the Westlaw ecosystem, typically at a higher, seat-based cost.
- Multi-year contracts are structurally rewarded with the biggest discounts, which pressures firms into 2 or 3 year commitments before they know if usage will justify the tier chosen.
- Content and features vary meaningfully between Edge and Advantage, so an apparently small monthly price difference can hide the absence of Practical Law, which many firms end up needing anyway.
- Switching away from Westlaw means retraining staff on Lexis search syntax and the Key Number System has no direct Lexis equivalent, which is a genuine cost that suppresses competitive shopping at renewal.
Pricing, plan by plan
Luminance
On request- Luminance$undefined/year
- Enterprise licensing quoted per organisation
- Scoped by user count and document volume
- Proof of concept normally run before contracting
Westlaw
On request- Westlaw Edge (solo and small firm, up to 10 attorneys)$undefined/month
- Single-circuit coverage from roughly $107 to $155 a month
- All-states-plus-federal coverage roughly $266 a month
- 2-year contracts around 12% off list, 3-year around 18% off
- Westlaw Advantage (firms of 11+ attorneys)$undefined/year
- Bundles Practical Law and secondary sources
- No published price, quote via sales representative
- CoCounsel Legal available as a seat add-on, reported around $639 per seat per month
Which should you pick?
Choose Luminance if
- You need anomaly detection.
- You work on Web, Windows.
- You also want contract negotiation.
Choose Westlaw if
- You need case law and statute database.
- You work on Web, iOS, Android.
- You also want keycite.
Questions people ask
- Is Luminance or Westlaw better?
- Neither clearly leads. Luminance starts at On request and Westlaw at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
- Which is cheaper, Luminance or Westlaw?
- Luminance starts at On request and Westlaw at On request.
- Does Luminance or Westlaw run on more platforms?
- Luminance runs on Web, Windows. Westlaw runs on Web, iOS, Android.
- What is Luminance best used for?
- Luminance is most often used for in-house teams auditing a contract estate for a specific exposure such as change of control, procurement and compliance functions reviewing supplier agreements at scale, transaction teams reviewing large contract populations against a deal deadline, negotiation teams applying a standard playbook consistently across many counterparties. Of those, in-house teams auditing a contract estate for a specific exposure such as change of control and procurement and compliance functions reviewing supplier agreements at scale are not what Westlaw is typically brought in for.
- What can Luminance do that Westlaw cannot?
- Luminance covers Anomaly detection, Contract negotiation, Due diligence review, Multi-language analysis. Westlaw covers Case law and statute database, KeyCite, Practical Law, CoCounsel Legal.
Answered from the vendors’ own pages
Luminance: Is Luminance's accuracy independently verified?
No independent verification has been published. It did not participate in the Vals Legal AI Report, the main lawyer-baselined benchmark, and the only named benchmark in its materials is one it built and ran itself. Treat the published figures as vendor claims and run a proof of concept on your own documents.
Westlaw: Can I still buy Casetext?
No. Casetext was retired on 1 April 2025. Its AI functionality continues as CoCounsel Legal, sold only as part of the Westlaw ecosystem.
Luminance: What do the ninety per cent time-saving claims mean?
They are unattributed marketing figures about time and cost rather than accuracy, published without methodology, dataset or baseline. They are not a measure of how often the software is right.
Westlaw: Why does Westlaw publish some prices but not others?
Self-service online pricing exists only for solo practitioners and firms up to 10 attorneys; larger firms are routed to a sales representative with no public rate.
Luminance: Who backs Luminance?
It launched in 2016 with backing from Invoke Capital, the fund founded by Mike Lynch, and has since raised further rounds led by March Capital and Point72 Private Investments.
Westlaw: What does CoCounsel Legal cost on top of Westlaw?
Reported figures put it around $639 per seat per month as an add-on, though this is not an official published rate and varies by contract.
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