Prices in GBP. Verified monthly. Always check the provider's site for the latest.
Pros & cons
Grammarly
Pros
+SOC 2 Type II and ISO 27001 certified — strongest compliance in the writing category
+Works across browser, desktop, Word, Google Docs, and email with one install
+Pro tier confirmed at £10/mo in GBP — transparent UK pricing
+Explicit opt-out from AI model training available in account settings
Cons
−Trains on user writing by default — opt-out required
−GDPR compliance not explicitly confirmed on accessed official pages
−Free AI prompt limit (100/mo) may feel restrictive for daily users
Sudowrite
Pros
+Explicit commitment to never training on user manuscripts — confirmed on pricing page
+Specialised fiction tools: character generation, outline, scene expansion
+Claims no rights over user content or generated output
+30+ language support across all plans
Cons
−No free tier — paid plans only
−GDPR and SOC2 not confirmed from official sources
−Fiction-only focus — not suited for marketing copy, email, or business writing
Our take— Grammarly wins
Based on our comparison of published pricing, features, and compliance data, Grammarly scores 8.1/10 to Sudowrite's 7.1/10. Grammarly pulls ahead with SOC 2 certification and ISO 27001 certification. Sudowrite counters with a no-training-on-your-data policy. Pick Grammarly if SOC 2 certification matters; pick Sudowrite if a no-training-on-your-data policy matters.