**Solo firms: $50-300/month

Solo firms: $50-300/month. Small firms: $500-2,000/month. Mid-size: $2,000-10,000/month. Large firms: $10,000-100,000+/month. Those are the 2026 benchmarks. If you're spending less, you're probably leaving productivity on the table. If you're spending more, make sure you're actually using what you're paying for.

The legal AI budget isn't one line item — it's a stack of tools serving different functions. Research, drafting, document review, contract management, practice management. The firms getting the best ROI aren't spending the most — they're allocating strategically based on what actually moves the needle for their practice.

Solo Practitioners: $50-300/Month

The sweet spot for solos is $75-150/month. Here's what that buys:

- Claude Team or ChatGPT Plus: $20-25/month — Your general AI assistant for research, drafting, client communications, and brainstorming - Legal research AI (vLex, Fastcase): $50-100/month — Case law access with AI-powered search - Spellbook or contract AI: $100-300/month — Only if contracts are a significant part of your practice

Most solos start with just Claude or ChatGPT ($20-25/month) and that alone delivers meaningful ROI. Add legal-specific tools only when the general AI tool isn't enough for your specific practice area. Don't overbuy. A solo spending $300/month on AI should be saving 5+ hours/month to justify it.

Small Firms (2-10 Attorneys): $500-2,000/Month

The stack for small firms typically includes:

- AI assistant (Claude Team/ChatGPT Enterprise): $25-60/user x 5-10 users = $125-600/month — Firm-wide AI access with admin controls - Legal research platform: $200-500/month — Westlaw/Lexis with AI features, or alternatives like vLex - Practice-specific AI: $100-500/month — Spellbook for contracts, EvenUp for PI, Docketwise for immigration - Document management AI: $100-300/month — If document handling is a significant bottleneck

Total: $500-2,000/month depending on firm size and practice mix. The most common mistake small firms make: buying enterprise tools they don't need. A 5-attorney firm doesn't need Harvey at $1,200/user/year when Claude Team + good prompts covers 80% of the use cases.

Mid-Size Firms (11-100 Attorneys): $2,000-10,000/Month

Mid-size firms need managed AI strategy, not just tools:

- Enterprise AI platform (Harvey or equivalent): $100-200/user x 20-50 power users = $2,000-10,000/month — Legal-specific AI for attorneys doing complex work - General AI (Claude Team/ChatGPT Enterprise): $25-60/user x all staff = $1,000-4,000/month — Firm-wide access for everyone including support staff - eDiscovery AI: $2,000-10,000/month — Relativity, Everlaw, or DISCO with AI features for litigation teams - CLM/Contract AI: $500-3,000/month — Ironclad, Luminance, or Juro depending on volume - Practice-specific tools: $500-2,000/month — Tools specific to the firm's primary practice areas

Total: $2,000-10,000/month. The key at this size: don't buy Harvey for everyone. Tiered deployment — premium tools for power users, general AI for everyone else — delivers better ROI than flat deployment.

Large Firms (100+ Attorneys): $10,000-100,000+/Month

Large firms are building AI infrastructure, not just buying tools:

- Legal AI platform (Harvey, custom deployments): $10,000-50,000/month — Firm-wide legal AI with knowledge management and compliance - General AI (enterprise licenses): $5,000-15,000/month — ChatGPT Enterprise or Claude Team for all staff - eDiscovery: $5,000-30,000/month — Enterprise Relativity or Everlaw licenses - CLM: $3,000-20,000/month — Ironclad, Luminance, or Agiloft at scale - Custom AI development: $5,000-30,000/month — Internal AI tools, custom integrations, dedicated AI staff - AI governance and training: $2,000-10,000/month — Compliance, monitoring, attorney training programs

Total: $10,000-100,000+/month. At this scale, the biggest cost isn't the tools — it's the people and processes to deploy AI effectively across hundreds of attorneys.

What Percentage of Revenue Should Go to AI?

2026 benchmark: 1-3% of gross revenue for AI-specific tools. This is separate from existing technology spend (which typically runs 3-6% of revenue).

- $1M revenue firm: $10,000-30,000/year on AI ($833-2,500/month) - $5M revenue firm: $50,000-150,000/year on AI ($4,166-12,500/month) - $25M revenue firm: $250,000-750,000/year on AI ($20,833-62,500/month) - $100M+ revenue firm: $1M-3M/year on AI ($83,333-250,000/month)

Firms spending under 1% are falling behind. Firms spending over 3% should audit whether they're getting ROI from every tool. The sweet spot is 1.5-2% of gross revenue allocated to AI tools, training, and governance combined.

The Bottom Line: Solo: $50-300/month. Small firm: $500-2K/month. Mid-size: $2K-10K/month. Large: $10K-100K+/month. Benchmark against 1-3% of gross revenue. Start with general AI tools and add specialized ones only when you've hit their limits.