Grammarly Pro costs $36 a month for three seats. It will catch your typos, flag passive voice, and tell you when a sentence sounds too formal or too casual. What it will not do is tell you whether that sentence sounds like you.
That gap matters more than most small teams realize. Your brand voice is not "professional" or "friendly." It is the specific cadence, vocabulary, and rhythm that makes your emails feel different from your competitor's emails. Grammarly can score tone on a generic scale. It cannot score whether a blog post sounds like the same company that wrote your landing page last month.
What Grammarly Pro Actually Does Well
Grammarly is legitimately good at its core job. It catches grammar mistakes faster than a human proofreader. It flags unclear phrasing. The tone detector will tell you if something reads as confident, worried, or analytical. The plagiarism checker works. The browser extension lives everywhere, Gmail, Google Docs, LinkedIn, Slack.
For solo writers who need a second pair of eyes on mechanics, it is hard to beat. The suggestions are fast, the interface is clean, and it does not try to rewrite your whole voice from scratch. It fixes what is broken and leaves the rest alone.
Where It Breaks Down for Marketing Teams
The problem starts when you have three people writing under one brand. Grammarly will make sure all three sound grammatically correct. It will not make sure all three sound like the same company.
Your social media manager writes punchy, one-line posts. Your blog writer uses longer sentences and more metaphors. Your email person leans on questions and second-person address. Grammarly sees three different tone profiles and flags nothing, because none of them are technically wrong. Your audience sees three different brands.
The tone suggestions Grammarly does offer are generic. "This sounds formal" is useful if formal is bad. It is not useful if your brand voice is specifically "warm but not cutesy, direct but not cold." Grammarly has no idea what your brand guidelines say. It has no idea what cadence you used in last quarter's campaign. It is checking tone against a universal standard, not against your standard.
And it does not rewrite. It highlights problems. If a paragraph does not match your voice, Grammarly will tell you it is "too wordy" or "unclear," but it will not show you what that paragraph should sound like in your actual brand voice. You are still doing the translation work yourself.
How FUEL's Brand Voice Checker Works Differently
FUEL's Brand Voice Checker starts by learning your voice. You feed it examples of your best content, emails, landing pages, social posts, whatever actually sounds like you. It builds a profile of your vocabulary, sentence structure, rhythm, and tone. Not "professional" or "casual." Your specific version of those things.
Then it scores new content against that profile. You paste in a draft blog post, and it tells you where the voice drifts. Too formal compared to your usual style. A word you never use. A sentence structure that does not match your cadence. It is not checking against Grammarly's universal tone standards. It is checking against you.
More importantly, it rewrites. If a paragraph does not match, FUEL will generate an alternative that does. You are not guessing how to fix it. You are seeing what it should sound like, based on how you have written everything else. That matters when you have three writers, two freelancers, and one intern all publishing under the same brand name.
It is part of the $79-a-month Growth plan that also includes your social scheduler, email builder, ad manager, landing page tool, and 30 other marketing functions. You are not paying $36 a month just for grammar checking. You are paying $79 a month for grammar checking plus everything else you were about to subscribe to separately.
The Real Cost Comparison
Grammarly Pro: $36/month for three users. $432 a year. Add your social scheduler ($29/month), email platform ($50/month), landing page builder ($40/month), and ad management tool ($60/month), and you are at $215 a month before you have even touched analytics, SEO, or CRM. That is $2,580 a year for five tools.
FUEL Growth: $79/month for all 35+ tools, including a brand voice checker that actually knows what your brand sounds like. $948 a year. The difference is $1,632 in year one, and that is with a conservative five-tool stack. Most small teams are paying closer to $1,600-$1,900 a month across their full marketing mix, which puts annual FUEL savings north of $18,000.
If you are a solo writer who just needs grammar help and you already love Grammarly's workflow, keep it. If you are a team publishing content under one brand name and you are tired of every writer sounding like a different company, FUEL will cost you half what you are paying now and actually enforce the voice you have been trying to maintain manually.