Grammarly Pro
An estimated forty-fold multiple month-to-month, most of it for checking that the free tier largely already does.
- Vendor
- Grammarly
- Category
- Writing
- Tier
- Pro
- Price / month
- $30
- Est. API cost
- $0.75
- Est. markup
- 40×
- Price checked
- 18 Sept 2026
- Verification
- verified
What the price actually is
$30/member/month month-to-month. Grammarly also advertises $12/member/month on annual billing, which cuts the multiple below to roughly a sixth of what is shown. The free tier already covers most non-generative checking, which is the comparison most readers should be making.
The usage this is priced against
40,000 words checked and 30 generative rewrites a month. Only the generative work is priced against a public API; the checking runs on Grammarly's own models and is given a separate allowance.
Someone using it half as much sees double the multiple. The assumption is the argument — if you disagree with it, the number below is not about you. Change it in the calculator.
The cost math, in full
Estimated monthly inference cost
Mid-tier frontier text model at $3.00 / 1M input tokens · 30 generative rewrites and tone adjustments
Mid-tier frontier text model at $15.00 / 1M output tokens
Grammar and clarity checking runs on Grammarly's own models rather than a public API. This is a deliberately generous allowance for that inference, not a measured figure — it makes the multiple smaller, not larger.
Rates come from a dated rate card of representative published API prices, not from the vendor. Nobody outside these companies knows what they actually pay; volume discounts and in-house serving both push real costs below these figures, which makes every multiple here a floor rather than a ceiling.
Why this verdict, not the number
Grammarly's models are its own and its integration surface is unusually wide, both of which are real work. The difficulty is the comparison a subscriber should actually make: not against an API, but against Grammarly's own free tier, which handles most of what most people use it for. A forty-fold multiple over estimated inference for the generative increment is a lot to pay for a narrow delta. Annual billing cuts it to around sixteen, and that is the version of this product that looks reasonable.
What the price buys besides tokens
- Proprietary model
- Distribution
- UX craft
In-house checking models refined over many years, running everywhere you type — browser, Word, desktop, mobile keyboard. The integration breadth is a permanent maintenance cost and it is most of what the subscription funds.
What you lose if you leave
Checking inside every text field you touch without thinking about it. That ambient presence is not something a script reproduces.
The honest cheaper path
LanguageTool, self-hosted or on its own cheaper plan, covers the checking. For rewrites, any assistant with your own key. Neither follows you into every input box.
Recompute it for yourself
Recompute this for your own usage
Scaling assumes your usage has the same shape as ours, just more or less of it. If your mix is different — far more output than input, say — the estimate drifts. It is an estimate either way.
Where every number came from
Price recorded 18 Sept 2026 · entry last reviewed 18 Sept 2026. Think something here is wrong? File a correction — we publish them, including the ones that embarrass us.