Wordtune Premium

Sentence rewriting delivered through a browser extension, where the unit of work is small enough that essentially the whole subscription is the interface rather than the generation.

WRAPPER

An interface and a system prompt over a public API. This describes an architecture, not a vendor’s conduct: shipping one is legal, common, and sometimes exactly what a customer wants.

Vendor
Wordtune (AI21 Labs)
Category
Writing
Tier
Unlimited
Price / month
$19.99
Est. API cost
$0.43
Est. markup
46×
Price checked
18 Sept 2026
Verification
verified
§1 · Billing

What the price actually is

$19.99/month on the Unlimited tier, billed monthly. Annual billing is advertised at $9.99/month, which halves the multiple below. A free tier with a daily rewrite cap exists and is the comparison most readers should be making.

§2 · Assumption

The usage this is priced against

150 sentence rewrites a month — the tone and length adjustments the product is bought for — at roughly 600 input and 600 output tokens each, on a small fast model.

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.

§3 · Arithmetic

The cost math, in full

Estimated monthly inference cost

90,000 input tokens$0.07

Small fast text model at $0.80 / 1M input tokens · 150 rewrites; the unit of work is a sentence, so both sides are short

90,000 output tokens$0.36

Small fast text model at $4.00 / 1M output tokens

Estimated cost$0.43
Price paid (Unlimited)$19.99
Estimated markup46×

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.

§4 · Reasoning

Why this verdict, not the number

The distinguishing feature of this category is how little inference a rewrite actually takes: a sentence in, a few sentences out, on a model that does not need to be large. That makes the gap between price and token cost wider here than almost anywhere else in the directory. The extension is genuinely convenient and the vendor has real language-model research behind it, but what a Premium subscriber is buying at the margin is the button in the text box.

What the price buys besides tokens

  • UX craft
  • Distribution

Rewriting where you are already typing, without a copy-paste round trip, is the product. The parent company does train its own models, which is more than most tools in this bracket can say, though the rewrite itself does not need them.

§5 · Leaving

What you lose if you leave

In-place rewriting inside any text field. For someone who rewrites constantly, removing the round trip is worth something real.

The honest cheaper path

The free tier covers light use. Beyond that, any assistant subscription rewrites sentences on request, and with an API key the estimated monthly token cost at this volume is well under a dollar.

§6 · Your numbers

Recompute it for yourself

Recompute this for your own usage

Your estimated cost
Your markup
Cost per unit of our assumption

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.

§7 · Sources

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.