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
Copy.ai
Pros
+Good range of marketing templates
+Generous free tier
+Easy to use
+Strong for short-form copy like ads and social posts
Cons
−Output quality inconsistent on longer content
−Less powerful than general LLMs for complex writing
−Brand voice features limited on lower tiers
Our take— Grammarly wins
Based on our comparison of published pricing, features, and compliance data, Grammarly scores 8.1/10 to Copy.ai's 7.6/10. Grammarly pulls ahead with ISO 27001 certification and a free tier. Copy.ai counters with GDPR compliance. Pick Grammarly if ISO 27001 certification matters; pick Copy.ai if GDPR compliance matters.