Last updated: February 2026
The average knowledge worker spends 28% of their workday on email. That’s 2.5 hours per day reading, writing, sorting, and responding to messages. Most of it is repetitive. Most of it doesn’t require your full brainpower. This is exactly what AI is good at.
I tested 6 AI email tools over the past two months, measuring actual time saved per day. The results ranged from “nice but marginal” to “how did I live without this.”
The Rankings
| Tool | Best For | Time Saved/Day | Price | Rating |
|---|---|---|---|---|
| Superhuman AI | Power email users | 45-60 min | $25-30/mo | 9/10 |
| Shortwave | Gmail users | 30-45 min | Free-$14/mo | 8.5/10 |
| Spark AI | Teams | 25-40 min | Free-$8/mo | 8/10 |
| Sanebox | Email triage | 20-30 min | $7-36/mo | 7.5/10 |
| Mailbutler | Outlook/Apple Mail | 15-25 min | $10-33/mo | 7/10 |
| ChatGPT + Gmail | Budget option | 15-20 min | $0-20/mo | 7/10 |
1. Superhuman AI — Best for Power Users
Superhuman was already the fastest email client before AI. Now it’s absurd. The AI features are deeply integrated into the workflow — not bolted on as an afterthought.
What it does:
“Write” generates complete email drafts from a few words. Type “decline meeting, suggest next week” and get a polished, professional email ready to send. The tone matching is excellent — it learns your writing style and mirrors it.
“Summarize” condenses long email threads into 2-3 sentences. When you return from vacation to 200 emails, this alone saves an hour.
“Auto-categorize” sorts incoming email into categories (action needed, FYI, newsletter, etc.) with high accuracy. Combined with keyboard shortcuts, you can triage 50 emails in 5 minutes.
What impressed me:
- Draft quality is the best I’ve tested — genuinely sounds like me
- Instant summaries of long threads save massive time
- “Ask AI” lets you query your inbox: “What did John say about the Q3 budget?”
- Keyboard-driven workflow means you never touch the mouse
- Split inbox with AI categorization is game-changing
What didn’t:
- $25-30/month is steep for an email client
- Gmail and Outlook only (no other providers)
- The learning curve for keyboard shortcuts is real
- Overkill if you get fewer than 30 emails per day
Pricing: $25/mo (Starter) → $30/mo (Business)
Best for: Executives, founders, salespeople, anyone drowning in 50+ emails per day.
2. Shortwave — Best for Gmail Users
Shortwave is what Gmail should be. It’s a Gmail client rebuilt with AI at the core. The AI assistant lives in your inbox and can answer questions about your email, draft responses, summarize threads, and even find information buried in old messages.
What impressed me:
- “AI Search” is incredible: “Find the contract John sent me in October” actually works
- Thread summaries appear automatically for long conversations
- Draft suggestions are contextually aware (it reads the thread before suggesting a response)
- Clean, modern interface that’s faster than Gmail’s web client
- Free tier is genuinely useful
What didn’t:
- Gmail only (no Outlook support)
- AI features can be slow during peak hours
- Some advanced features require the paid tier
- Mobile app is less polished than desktop
Pricing: Free (basic AI) → $7/mo (Pro) → $14/mo (Business)
Best for: Gmail users who want AI-powered email without switching to a premium client like Superhuman.
3. Spark AI — Best for Teams
Spark has been a solid email client for years. The AI additions make it particularly good for teams — shared drafts, collaborative responses, and AI that understands your team’s communication style.
What impressed me:
- AI adapts to your team’s tone (formal for clients, casual for internal)
- Shared inbox with AI-suggested responses
- “Gist” feature summarizes newsletters and long emails
- Cross-platform (Mac, iOS, Android, Windows)
- Generous free tier
What didn’t:
- AI quality is slightly below Superhuman and Shortwave
- Can feel cluttered with features
- Sync issues occasionally between devices
Pricing: Free (basic) → $5/mo (Premium) → $8/mo (Business)
Best for: Small teams that share inboxes or collaborate on email responses.
4. Sanebox — Best for Email Triage (Works with Any Client)
Sanebox isn’t an email client — it’s an AI layer that works with your existing email setup (Gmail, Outlook, Yahoo, anything). It automatically sorts incoming email into folders: important, newsletters, CC’d, bulk, etc.
The beauty is simplicity. You don’t change your email client. You don’t learn new software. Sanebox works silently in the background, and your inbox suddenly has 60-70% fewer emails in it because the unimportant ones are sorted away.
What impressed me:
- Works with any email provider and any email client
- “SaneBlackHole” — drag an email there and you never hear from that sender again
- “SaneRemindMe” — emails reappear at a specified time
- “SaneNoReplies” — flags emails you sent that didn’t get a response
- Set-and-forget: once configured, it just works
What didn’t:
- No AI writing assistance (it’s purely for sorting)
- Takes 1-2 weeks to learn your preferences
- Occasional false positives (important email sorted as unimportant)
- Pricing tiers are confusing
Pricing: $7/mo (Snack) → $12/mo (Lunch) → $36/mo (Dinner)
Best for: Anyone overwhelmed by email volume who doesn’t want to switch email clients.
5. The Free Option: ChatGPT + Your Email
You don’t need a dedicated AI email tool. ChatGPT (free or Plus) handles most email tasks:
Draft emails: “Write a professional email declining a meeting invitation. Suggest rescheduling next week. Keep it brief and friendly.”
Summarize threads: Paste a long email thread and ask “Summarize this conversation and list the action items.”
Translate: “Translate this email to professional Japanese” — better than Google Translate for business communication.
Tone adjustment: “Rewrite this email to sound less aggressive but still firm.”
The workflow is clunkier (copy-paste between ChatGPT and your email client), but it’s free and surprisingly effective. If you handle 10-20 emails per day, this might be all you need.
How to Choose
Get fewer than 20 emails/day? ChatGPT + your current email client. Free and sufficient.
Get 20-50 emails/day? Shortwave (free tier) or Spark. Good AI features without a big investment.
Get 50-100 emails/day? Superhuman or Shortwave Pro. The time savings justify the cost.
Get 100+ emails/day? Superhuman + Sanebox. Nuclear option. Superhuman for speed, Sanebox for pre-filtering.
Don’t want to switch email clients? Sanebox. Works with everything, sorts silently.
The Math
If you earn $50/hour and spend 2.5 hours/day on email:
- Saving 30 minutes/day = $12,500/year in recovered time
- Saving 60 minutes/day = $25,000/year in recovered time
Even Superhuman at $300/year pays for itself in the first week. The question isn’t whether AI email tools are worth it — it’s which one matches your workflow.
Affiliate links below where available. All tools tested over 2+ months.