Claude cost calculators audited, 4 of 9 print a cancelled rise
Every figure captured 29 August 2026. The pages measured can change at any time, so treat each reading as a dated snapshot, not a verdict on the site today.
We fetched nine Claude cost calculators that rank for this topic on 29 August 2026 and compared every Claude price they display against two independent sources read the same day, the Anthropic pricing page on platform.claude.com and the OpenRouter models API. Four of the nine still tell readers that Sonnet 5 rises to $3 / $15 on 1 September. A fifth, vortenza.com, prints $3 / $15 as today's Sonnet 5 rate with no date attached. Anthropic's own page, fetched at 10:01 UTC that morning, says: The $2/$10 per million input/output token pricing for Claude Sonnet 5, announced at launch as introductory pricing through August 31, 2026, is now the standard price. The previously scheduled increase to $3/$15 per million input/output tokens on September 1, 2026 will not occur.
Two of the nine display a wrong current-generation price. The widest gap is vortenza.com, which prints Opus 5 at $15 / $75 against a corroborated $5 / $25, a 3x gap on both input and output. Two of the nine list no Claude 5 model at all. Only benchlm.ai and calculatequick.com surface the 1-hour cache write tier that sits in Anthropic's own table.
Seven of nine matched both sources on every comparable row. Only one of those, aicodex.to, did so without also printing the cancelled September increase or dropping the Claude 5 family entirely. A correct table can still lead a reader to the wrong budget when the prose around it has expired.
How we measured this
We fetched two sources on 29 August 2026 at 10:01 UTC, the Anthropic pricing page in both its markdown and HTML forms, and the OpenRouter models API. A rate is corroborated when both sources agree. They agreed exactly on every model both carry. Mythos 5 is not listed on OpenRouter, so its one comparison is against Anthropic alone. Nine calculator pages were then fetched by curl between 10:01:43 and 10:01:48 UTC, and each capture's byte count and SHA-256 are recorded. A tenth page, the pricepertoken.com provider page, returned HTTP 404, so we replaced it with that site's Opus 4.7 token counter page, which carries the same model table. We quote every price as the raw text around the model name in the served HTML, at a recorded byte offset. A displayed rate counts as differing when it moves away from the corroborated pair on a model both sources carry. Rates are USD per 1M tokens. Cache, batch and context columns were not scored. The feature flags in the embedded data, such as cache write or tokenizer, are keyword hits in the page text and were not tested by use. The full per-site readings are embedded in this page's source as JSON.
| Site | Date label on page | Rows checked | Rows differing | Prints the cancelled Sept 1 rise | Lists a Claude 5 model |
|---|---|---|---|---|---|
| vortenza.com | Last verified August 2026 | 6 | 4 | no | yes |
| pricepertoken.com | Last updated: August 28, 2026 at 08:37 AM | 9 | 1 | no | yes |
| calculatequick.com | Updated July 24, 2026 with Claude Opus 5 | 13 | 0 | yes | yes |
| invertedstone.com | none | 11 | 0 | yes | yes |
| benchlm.ai | as of August 29, 2026; Opus 5 is $5/$25 | 11 | 0 | yes | yes |
| costgoat.com | LAST UPDATED: AUGUST 15, 2026 | 11 | 0 | yes | yes |
| flowlyn.com | none | 7 | 0 | no | no |
| techsy.io | updated quarterly as model pricing changes | 2 | 0 | no | no |
| aicodex.to | Prices last verified August 21, 2026 against Anthropic’s official pricing page | 4 | 0 | no | yes |
Site by site, measured on 29 August 2026
vortenza.com
Page label reads Last verified August 2026. Comparable rows checked, 6. Rows matching both sources, Fable 5, Sonnet 4.6.
| Model | Displayed | Both sources say | Gap in and out |
|---|---|---|---|
| Opus 5 | $15 / $75 | $5 / $25 | 3x / 3x |
| Sonnet 5 | $3 / $15 | $2 / $10 | 1.5x / 1.5x |
| Haiku 4.5 | $0.8 / $4 | $1 / $5 | 0.8x / 0.8x |
| Opus 4.7 | $15 / $75 | $5 / $25 | 3x / 3x |
Four of its six comparable rows differ from both sources. The page prints Claude Opus 5 new 200K $ 15.00 $ 75.00
and Claude Opus 4.7 200K $ 15.00 $ 75.00
. Anthropic's own table lists Opus 5 at $5 input and $25 output, and OpenRouter carries the same. That is a 3x gap on the flagship. Sonnet 5 shows Claude Sonnet 5 best value · selected 200K $ 3.00 $ 15.00
, the $3 / $15 rate Anthropic announced and later withdrew, 1.5x the corroborated $2 / $10. Haiku 4.5 shows Claude Haiku 4.5 200K $ 0.80 $ 4.00
, which matches Anthropic's listed Haiku 3.5 rate, 0.8x the corroborated $1 / $5. The page says Last verified August 2026 and lists every context as 200K.
pricepertoken.com
Page label reads Last updated: August 28, 2026 at 08:37 AM. Comparable rows checked, 9. Rows matching both sources, Opus 4.7, Haiku 4.5, Sonnet 5, Sonnet 4.6, Opus 4.8, Opus 5, Fable 5, Opus 4.1.
| Model | Displayed | Both sources say | Gap in and out |
|---|---|---|---|
| Mythos 5 | $11 / $55 | $10 / $50 | 1.1x / 1.1x |
The provider page at pricepertoken.com/provider/anthropic returned HTTP 404 at capture, so the rows come from the model table on its Opus 4.7 token counter page. Eight of nine rows match. The one that differs is Mythos 5, printed as claude-mythos-5 $11.000 $55.000
against the Anthropic sheet's $10 / $50, a 1.1x gap. OpenRouter does not list Mythos 5, so this row is checked against Anthropic alone. The page carries the freshest label in the set, Last updated: August 28, 2026 at 08:37 AM.
calculatequick.com
Page label reads Updated July 24, 2026 with Claude Opus 5. Comparable rows checked, 13. Rows matching both sources, Fable 5, Mythos 5, Opus 5, Opus 4.8, Opus 4.7, Opus 4.6, Opus 4.5, Opus 4.1, Sonnet 5, Sonnet 4.6, Sonnet 4.5, Haiku 4.5, Haiku 3.5.
Every comparable row matches. The problem is the Sonnet 5 story. The dropdown reads Claude Sonnet 5 – $2 / $10 (intro thru Aug 31)
and the reference table lower on the page reads Claude Sonnet 5 $3.00 $15.00 Active; 1M context; intro $2 / $10 through Aug 31, 2026
. The prose says It launched at introductory pricing of $2 input and $10 output per million tokens through August 31 2026, after which it moves to standard pricing of $3 input and $15 output
. Anthropic's page, read the same day, says the increase will not occur. A reader who plans a September budget from this page prices Sonnet 5 at 1.5x.
invertedstone.com
No date label on the page. Comparable rows checked, 11. Rows matching both sources, Opus 5, Opus 4.8, Opus 4.7, Opus 4.6, Sonnet 5, Sonnet 4.6, Sonnet 4.5, Fable 5, Haiku 4.5, Opus 4.5, Opus 4.1.
All eleven comparable rows match, and the page has no visible date label. It then adds a second Sonnet 5 card, Claude Sonnet 5 (from Sep 1, 2026) Standard Sonnet 5 pricing starting September 1, 2026 Input: $ 3.00 /1M tokens Output: $ 15.00 /1M tokens
, next to the intro card Introductory Sonnet 5 pricing through August 31, 2026 Input: $ 2.00 /1M tokens Output: $ 10.00 /1M tokens
. The Sep 1 card is the cancelled price. It also lists Claude Opus 5 (Fast) Fast mode (~2.5× speed) at 2× Opus 5 base price Input: $ 10.00 /1M tokens Output: $ 50.00 /1M tokens
, which OpenRouter carries at $10 / $50 but the Anthropic table does not list as a row, so we did not score it. No Mythos 5 row.
benchlm.ai
Page label reads as of August 29, 2026; Opus 5 is $5/$25. Comparable rows checked, 11. Rows matching both sources, Fable 5, Opus 5, Sonnet 5, Haiku 4.5, Mythos 5, Opus 4.8, Opus 4.7, Opus 4.6, Opus 4.5, Sonnet 4.6, Sonnet 4.5.
All eleven comparable rows match, and the page's embedded JSON names platform.claude.com as its price source. The label reads as of August 29, 2026; Opus 5 is $5/$25. Yet its Sonnet 5 row is dated Claude Sonnet 5 claude-sonnet-5 Current $2 $0.2 $10 $1 $5 1M Through Aug 31, 2026 Claude API pricing
and the prose says Sonnet 5 is billed at its temporary $2/$10 rate through August 31 rather than the later $3/$15 standard rate
. The rate is right and the framing expired on 31 August.
costgoat.com
Page label reads LAST UPDATED: AUGUST 15, 2026. Comparable rows checked, 11. Rows matching both sources, Opus 5, Fable 5, Opus 4.8, Sonnet 5, Opus 4.7, Sonnet 4.6, Opus 4.6, Opus 4.5, Sonnet 4.5, Opus 4.1, Haiku 4.5.
All eleven comparable rows match and the page is plainly dated LAST UPDATED: AUGUST 15, 2026. The Sonnet 5 card reads Claude Sonnet 5 (claude-sonnet-5) Context 1M Quality 88 Per 1M Tokens In: $ 2.00 Out: $ 10.00
. The intro prose above the cards reads Claude Sonnet 5 at $3 / $15 standard ($2 / $10 introductory through Aug 31, 2026) with 1M context
, which calls $3 / $15 the standard rate. Anthropic's page now calls $2 / $10 the standard rate. No Mythos 5 row.
flowlyn.com
No date label on the page. Comparable rows checked, 7. Rows matching both sources, Opus 4.6, Opus 4.5, Sonnet 4.6, Sonnet 4.5, Haiku 4.5, Opus 4.1, Haiku 3.5.
The seven rows it prints are right. The table header reads Claude 4.6 & 4.5 Series (Latest Frontier), and there is no date label. Fable 5, Mythos 5, Opus 5, Opus 4.8, Opus 4.7 and Sonnet 5 are absent. A reader cannot price any Claude 5 model here.
techsy.io
Page label reads updated quarterly as model pricing changes. Comparable rows checked, 2. Rows matching both sources, Opus 4, Sonnet 4.
An OpenAI calculator with three Claude rows, all from the 4.0 generation. Opus 4 and Sonnet 4 match the retired rates on Anthropic's sheet. The third row, Claude Haiku 4 $0.80 $4.00 $0.08
, names a model that does not exist on the official sheet, so it was not scored. The page says it is updated quarterly as model pricing changes. Every current generation model is absent.
aicodex.to
Page label reads Prices last verified August 21, 2026 against Anthropic’s official pricing page. Comparable rows checked, 4. Rows matching both sources, Fable 5, Opus 5, Sonnet 5, Haiku 4.5.
Credit where due. Four rows, all four match both sources, no cancelled price rise in the prose, and a plain label, Prices last verified August 21, 2026 against Anthropic’s official pricing page. Coverage is thin. Mythos 5, Opus 4.8, Opus 4.7 and Sonnet 4.6 are absent.
What to do
Read the price from the vendor before you trust a calculator. The Anthropic pricing page carries base input, 5-minute cache write, 1-hour cache write, cache read and output for every model, and the note that cancels the Sonnet 5 increase. The OpenRouter models API is a second independent read of the same rates. On this site the Claude API pricing page holds the snapshot rates we corroborated, and the LLM cost calculator turns a token count into money from those rates. The same audit method was run on OpenAI calculators, see how accurate OpenAI cost calculators are, and the cases where public sources disagree with each other are on the price source disagreement page.
Why calculators drift
Two patterns cover every gap in the readings. The first is an announcement that outlived its correction. Sonnet 5 launched with a $2 / $10 rate described as introductory through 31 August 2026. Four pages repeat that framing and the $3 / $15 standard rate that was to follow. Anthropic then made $2 / $10 the standard price and said the increase will not occur. The four pages carried the old sentence at capture, and one of them, benchlm.ai, is labelled as of 29 August 2026, the same day we read the correction. The second is a table that was built for one generation and never grew. flowlyn.com stops at Opus 4.6. techsy.io stops at Opus 4. vortenza.com has a Claude 5 section but prints Opus 5 and Opus 4.7 at the $15 / $75 Anthropic lists for the retired Opus 4.1, and Haiku 4.5 at the Haiku 3.5 rate.
A date label did not predict accuracy in this set. The freshest label, pricepertoken.com at 28 August, sits on a page with a wrong Mythos 5 row. The clean page, aicodex.to, is labelled 21 August. Find the date, then check one flagship rate against the vendor. If the flagship is wrong, close the tab.