Offline Currency Converter
Convert between 47 currencies with a local rate table that works with no connection.
A Converter, Not A Rate Feed
Currency converters on the web need a connection, which is exactly what you do not have when you are standing in a shop abroad with no roaming. This one ships its rate table with the page and stores it in your browser, so it keeps working in aeroplane mode.
The trade-off is stated rather than hidden: these rates are fixed, and exchange rates move every second. The banner at the top shows how old the table is and changes tone as it ages, because a converter that quietly uses stale rates is worse than one that has none.
Key features
- Works with no connection — the rates ship with the page and are stored locally.
- 47 currencies — every pair, computed through the dollar from a single column of numbers.
- Editable rates — type a current rate for any currency and it is kept for next time.
- Honest freshness banner — the date the rates carry, and how long ago that was.
- A table of common amounts — which is usually faster than typing, when you are converting a price in your head.
This tool runs entirely inside your browser using native Web APIs. Your files and text are never uploaded to a server, never logged and never shared with third parties.
How to use: Offline Currency Converter
- Choose the currencies
Or use the swap button to reverse them. - Enter an amount
The conversion and the reverse rate update as you type. - Check the freshness banner
If the rates are old and the amount matters, update them. - Update a rate if you need to
Type the rate against one US dollar; it is stored in this browser only.
Technical specifications
| Processing location | Entirely in your browser — no server round trip |
|---|---|
| Data uploaded | None. Files and text never leave your device |
| Price | Free — no account, no trial, no usage cap |
| Category | Converters |
| Works offline | Yes, once the page has loaded |
| Browser support | Chrome 90+, Edge 90+, Firefox 90+, Safari 15+ |
| Interface languages | English, 中文, हिन्दी, Español, العربية |
Frequently asked questions
How accurate are the built-in rates?
They were accurate on the date shown in the banner and are a fixed table thereafter. For estimating a restaurant bill or a shop price that is entirely adequate. For anything where the number matters — an invoice, a transfer, an expense claim — check a live source and update the table, which takes a few seconds.
How do I update the rates?
Open "Update the rates", pick a currency, and type what one US dollar is worth in it. The value is stored in your browser and survives closing the tab. Set the date at the same time so the freshness banner stays honest.
Why is everything converted through the dollar?
Because it means every one of the 2,209 possible pairs works from a single column of 47 numbers. The alternative is a full matrix, which is far more to store and far more to keep current. It is also how the interbank market itself is quoted for most pairs.
Why does the rate I get at a bureau differ from this?
Because the rate here is the mid-market rate — the midpoint between buying and selling. A bureau de change, a card issuer and a bank each add a spread, typically two to five percent and sometimes much more at an airport. This gives you the number to compare their offer against.
Is my data sent anywhere?
No. There is no network request at all, including for rates. Everything you type stays in the page, and any rate you save is stored in your own browser.