Methodology and sources
Every number on this site comes from an official or market source, is stored with the time it was read, and is never typed in by hand.
Sources
| Source | What we take | How often | Last successful read |
|---|---|---|---|
| Bank of Tanzania | Official indicative buying, selling and mean rates for about 38 currencies against the shilling. | Checked several times a day. The Bank of Tanzania publishes once per business day. | 20 Okt 2026, 11:17 EAT |
| fawazahmed0 currency-api | A global reference rate (units of each currency per US dollar), converted to TZS per unit. | Daily. | 20 Okt 2026, 11:15 EAT |
| CRDB | Buying and selling board rates published on the bank's website. | Checked several times a day. | 20 Okt 2026, 11:16 EAT |
| NBC | Telegraphic-transfer (T.T.) buying and selling rates from the bank's published rate sheet (PDF). | Checked several times a day; the bank updates its sheet about once a day. | 20 Okt 2026, 11:16 EAT |
| Stanbic | Buying and selling rates from the bank's published indicative rate sheet (PDF). | Checked several times a day; the bank updates its sheet about once a day. | 20 Okt 2026, 11:16 EAT |
What “indicative” means
Bank of Tanzania rates are reference rates calculated from market activity. They are not a price at which anyone is obliged to deal. Real transactions at banks and bureaux de change vary with the amount, fees, the time of day and the counterparty.
How we calculate
- Mean
- The Bank of Tanzania mean is the figure it publishes, shown unchanged. It is the midpoint of its buying and selling rates.
- Spread
- Selling rate minus buying rate, in TZS, and as a percentage of the midpoint of the two.
- Change
- The latest Bank of Tanzania mean compared with the most recent published mean on or before 1, 7 and 30 days earlier, on 31 December of the previous year (year to date), and one year earlier.
- Direction
- All rates are shillings per one unit of foreign currency. A rising rate means the shilling weakened; a falling rate means it strengthened.
- Market rate against the official rate
- The latest mid-market rate minus the latest Bank of Tanzania mean, in TZS and %. The market feed is a global aggregate and can be stale or wrong for a thinly traded currency like the shilling, so clearly unreliable days are excluded.
- Best bank
- The highest buying rate (best if you sell foreign currency) and the lowest selling rate (best if you buy it) among banks whose rate was read in the last 36 hours.
Bank of Tanzania data
The Bank of Tanzania publishes its indicative table once per business day. Its page can show a new date with the previous day's numbers before the new table is out; we mark those readings and keep showing the last genuine table.
Older rates come from the Bank of Tanzania's own history search. That table repeats the last rate over weekends and holidays, and its date labels can differ from the live table by a day, so we keep a date only when its full table differs from the day before. For the most recent days the history table can lag behind the live table.
Bank rates
Banks publish board rates on their websites, some as PDF rate sheets. We read them automatically. They are indicative and can differ at the counter. Where a bank publishes several rate types we use its telegraphic-transfer buying and selling rates.
Data quality
Automated checks reject zero or negative rates and rates where buying exceeds selling, and hold back any live value that moves more than 3% from the previous one. We found 85 clearly wrong points in source data (for example decimal-point typos, and a stale market feed in December 2024). They are left out of charts and calculations but never deleted from the stored record.
Limits
This is a data service, not financial advice. Rates can be delayed or wrong at the source. Check the rate with your bank or the Bank of Tanzania before you transact.
How to cite
Name the source and the date you read it. A suggested form:
Bank of Tanzania indicative exchange rates, via Kiwango cha Dola (https://maresfield-cmyk.github.io/kiwango-cha-dola/sw/), accessed 20 Okt 2026.
Data
The data behind every page is available as JSON and CSV. Please credit this site when you use it.