CalculateItNow vs Omni Calculator
The largest catalogue in the category — 3,923 calculators — with named authors and reviewers on every page.
Everything said here about Omni Calculator was read off their live site on , and the pages we opened are listed at the bottom. They may have changed since — if something below is out of date, believe them and not us.
Omni Calculator is the largest general-purpose calculator site we compared. On the day this page was checked its home page read “Your life in 3923 free calculators”, spread across 14 categories: 686 in Math, 615 in Finance, 546 in Physics, 439 in Health, 329 in Conversion, and on down to 34 in Ecology.
It is a staffed operation with a published editorial policy — a four-stage process of designing the calculator, writing the article, having a second specialist review both, and proofreading — and it states plainly that “None of our content is automatically generated by artificial intelligence (AI).” It funds itself with display advertising: its ads.txt names Ascendeum as its manager domain and authorises Google along with several hundred other exchange entries.
We have 331 calculators. On breadth this is not a close contest, and everything below is about the things that are not breadth.
What Omni Calculator does better than us
Twelve times the catalogue
3,923 against our 331. We cover the common questions and a fair slice of the long tail, but ask for a Punnett square or a titration and they have a calculator for it — we checked both — and we do not. Breadth is their whole strategy, and it works.
Real depth in the sciences
546 physics calculators, 196 statistics, 111 biology and 108 chemistry, by their own category counts. Our entire science category is 29 calculators — some physics, some chemistry, no biology at all — and we do not have a category for chemistry or biology to put more in. For a problem set, this one is easy to write: use Omni.
A person's name, and their qualification, on the page
Their mortgage calculator names four creators and two reviewers; the editorial policy describes how creators are vetted and coached. We deliberately publish no bylines, because we have no credentialed staff and will not invent any. If your assignment, your editor or your own judgement requires a qualified human to have signed off, they have that and we do not.
Years of editing behind each page
Their pages carry publication and update history and the policy commits to “regular audits for the content that may change with time, especially in health and finance”. Our oldest calculator was published on 8 September 2026. Theirs have been read, corrected and re-reviewed for years.
Sources chosen by subject specialists
The mortgage page cites Cipra's Financial and Insurance Formulas (2006) — a textbook, picked by someone who knows the literature. We cite sources too, but ours are chosen for a general reader, not for a specialist.
Side by side
| Omni Calculator | CalculateItNow | |
|---|---|---|
| Calculators | 3,923 (stated on their home page) | 331 |
| Named authors and reviewers | Yes — the mortgage page credits four creators, including Tomasz Jedynak, PhD, and two reviewers | None. We publish tests and sources instead of credentials. |
| Display advertising | Yes — ads.txt lists Ascendeum as manager plus Google and hundreds of exchange entries | None, and no cookie-consent banner. |
| Embeddable widget | Free, after a form with your name, email and domain; the code arrives by email once approved. The Omni logo must stay visible and a backlink is required. | Free and instant, no email and no approval. We ask you to keep a one-line text credit whose wording you choose. |
| AI calculator builder | Yes — describe an idea at /custom/new. A PRO tier sets your colours and removes watermarks. | Yes — /new. The engine validates every generated formula, and generated pages are labelled and left out of the index until reviewed. |
| API for developers or AI assistants | Not offered on any page we checked | Free JSON API and a hosted MCP server, no key |
| Editorial policy | Published, with a four-stage review process | Published at /about: the AI routes and explains, and never does the arithmetic |
What we do that they don’t
Nothing on the page is selling anything
No ad slots, no ad-tech, no consent banner, no upsell and no account. Omni's advertising is a legitimate way to pay for 3,923 calculators and a team to write them; the trade-off is advertising on the page. We have made the opposite trade, and have no revenue at all.
Embedding takes ten seconds, not an application
Every calculator here has an /embed/<slug> version. You copy three lines from the page and paste them. There is no form, no email address, no approval step, no logo requirement — we ask you to keep a one-line text credit and you choose how it reads.
An API and an MCP server
Any calculator can be called over HTTP with no key, and an AI assistant can connect to our MCP server and run the same tested code rather than doing the arithmetic in its head. We did not find an equivalent on the pages we checked.
Working backwards, and what-if, built into the engine
Goal seek — “what rate gets my payment to $2,000?” — is on 265 of our 331 calculators, and a sensitivity table showing which input moves the answer most is on 258. They are engine features, so they arrive with every new calculator rather than being written per page.
Every calculation is a link
Your inputs live in the URL, so sending someone your exact scenario is copying the address bar, and reopening it next year gives the same numbers. Nothing is stored and no account exists to forget the password to.
Where we are weak
Against Omni Calculator specifically, these are the things you would be giving up by using this site:
- 331 calculators to their 3,923. For anything niche, they will have it and we will not.
- Almost nothing in physics, chemistry or biology.
- No bylines, no credentialed reviewers, and no editorial staff — by choice, but the effect on you is the same: you are trusting tests and cited sources rather than a named expert.
- Every page on this site was written in September 2026. There is no track record, nobody has corrected us yet, and no one has heard of us.
- No mobile app, and no translations — this site is English only.
Use Omni Calculator instead if…
- The calculator you want is not among our 331 — search here first, it takes a second, then go straight there.
- You need biology, or physics and chemistry past the standard handful of formulas — hundreds of pages there against 29 here.
- You need to point at a named, credentialed author and reviewer for a piece of work.
- You want the page you embed to carry a brand your readers already recognise.
Go to Omni Calculator. We would rather you got the right answer somewhere else than the wrong one here.
How we checked
On we opened these pages and took the claims above from what they said that day. Nothing here comes from memory or from a third-party estimate; where we could not verify something, we left it out rather than guessing.
- Home page (calculator count and category counts)
- Mortgage calculator (bylines, reviewers, cited source)
- Editorial policies
- Calculator widgets (what an embed requires)
- AI calculator builder
- ads.txt (how the site is funded)
- Punnett square calculator (a page they have and we do not)
- Titration calculator (likewise)
Our own figures are counted from the code that builds this site, at the moment you loaded this page: 331 calculators, 265 of them with goal seek and 258 with a sensitivity table. The test count is the exception — nothing here can count it — so it was taken by running the suite on 11 September 2026 and is written as a floor, because it goes up most weeks.