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Grammarly’s pricing page shows Pro at $12 a month. That is true only if you pay for the whole year at once. Pay month to month and the same plan is $30. The headline number is the annual price divided by twelve, and the gap between the two is the entire question.
The decision comes down to this: will you use Pro for more than five months? If not, the cheapest plan isn’t the one with the lowest monthly figure.
What Grammarly charges, from its own page
All figures were read from Grammarly’s own plans page (grammarly.com/plans) on 10 October 2026, in US dollars.
| Plan | Billed | Price | Effective monthly | Over 12 months |
|---|---|---|---|---|
| Free | n/a | $0 | $0 | $0 |
| Pro, annual | Once a year | $144 | $12 | $144 |
| Pro, quarterly | Every 3 months | $60 | $20 | $240 |
| Pro, monthly | Every month | $30 | $30 | $360 |
Enterprise is “contact sales” and isn’t priced publicly, so it isn’t covered here.
Two things are worth noticing. First, the monthly plan costs 2.5 times the annual one: $360 against $144 over a year, a difference of $216. Second, the pricing page’s big “$12” never mentions that it’s an annual figure. It sits next to a “Try for free” button, with the line “Email reminder 2 days before trial ends” and a “7-day Free Trial” call to action. We could not find the renewal or auto-renew terms on the pricing page itself, so read them at checkout before entering a card. Our guide to free trials and how not to get caught out covers what to check.
What you get for the money
Grammarly’s own comparison table is clear about the split.
Free covers writing without spelling and grammar mistakes, a view of your writing tone, and 100 AI prompts a month.
Pro adds, per the same table: rewriting full sentences, adjusting tone, writing fluently in English, inclusive-language suggestions, citation consistency, AI-generated-text detection, plagiarism detection, priority support, and 2,000 AI prompts a month.
So the free plan does the core job: catching errors. Pro is for people who want the tool to rewrite for them, check for plagiarism, or lean heavily on AI generation. If your problem is typos and commas, you are paying $144 for features you are not using.
The three calculations
1. Annual versus monthly break-even. Divide the annual price by the monthly price: $144 ÷ $30 = 4.8. If you will use Pro for five months or more in a year, annual is cheaper. Under five, monthly is. Anyone who would use it for a single month, such as a thesis deadline, pays $30, not $144.
2. Quarterly versus monthly. $60 ÷ $30 = 2. Quarterly beats monthly from the third month onward. It’s the right plan for a one-semester project: $60 for three months, instead of $90 at the monthly rate.
3. Is Pro worth it to you? This one needs your numbers, not ours. Take the annual price and divide it by your hourly value:
$144 ÷ your hourly rate = hours Pro must save you in a year
At $25 an hour, that is 5.8 hours across 12 months, or about 29 minutes a month. At $50 an hour it is 2.9 hours. If you write professionally every week and rewrites save you that, Pro clears the bar easily. If you send a handful of emails a week, it will not, and no amount of tone suggestions changes the arithmetic. We can’t tell you how many minutes it saves you, because we haven’t measured that and it differs for everyone. That is the number to estimate honestly.
What to try first
Before paying anyone, check what you already have. A Microsoft 365 subscription includes Word, which has its own spelling and grammar checking; our Microsoft 365 breakdown covers what that costs. If you only want a second pair of eyes on grammar, LanguageTool advertises a free plan alongside a paid Premium tier. We could not read its pricing, which is rendered by JavaScript, so we have no figures for it and can’t compare it on cost.
If it’s the AI side you are paying for, compare against what your other tools already include. Our AI subscription comparison lists what ChatGPT, Claude and Google charge, and Grammarly’s 2,000 prompts a month only makes sense if you are not already paying for one of those. Paying for two overlapping tools is the classic way subscriptions pile up; the annual versus monthly guide has the framework for deciding when upfront payment is a saving and when it is just a larger bill.
The verdict
Pro is worth it if you write for a living or for a deadline, you have actually hit the limits of the free plan, and you will use it for at least five months. In that case choose annual at $144.
Choose quarterly or monthly if you have one defined project, like a dissertation, a job-application push or a semester of coursework. Pay $60 for three months and cancel. Set a calendar reminder the day you start.
Do not buy it if you mostly write short emails and messages, you only want spelling and grammar checked, or you already pay for an AI assistant that rewrites text. The free plan covers your use. That is most casual writers, and for them Pro is $144 a year for features they will not open.
Do not take the annual plan “to save money” if you are unsure you will keep using it. A $144 annual plan you stop using in month three has cost you $48 a month for the three months you used it.
Prices verified at grammarly.com/plans on 10 October 2026. Plans and trial terms change; confirm the renewal terms at checkout. LanguageTool pricing could not be confirmed and is not quoted.