eqlx.org / eqlx-bankmath
Python library · MCP server · v0.1 · Apache-2.0
The number a bank assistant must not guess.
An instalment, an interest charge or a commission has one right value, down to the kuruş (a hundredth of a lira). eqlx-bankmath computes it for bank products in Türkiye, so an AI agent asks for the number instead of working it out itself.
What goes in, what comes out
No model inside, no network. Same input, same answer.
You give
- the product and its amounts
- the rate and the dates
- fees, payments, balances
- the bank's conventions, if you know them
eqlx-bankmath computes
- the levies in force on that date
- interest, period by period
- every row rounded to the kuruş
- the yearly cost of the whole deal
You get
- the number, and the rows behind it
- the decree or article it rests on
- the conventions that were used
- whether a fee or rate is over its ceiling
One loan, start to finish
A consumer loan of 100,000 TL. What you enter, what the tool computes, what comes back.
1You enter the loan
Five values.
| Amount | 100,000 TL |
| Repayment | 24 monthly instalments |
| Interest rate | 3.99 % a month |
| Paid out on | 10 November 2026 |
| Allocation fee | 500 TL |
2The tool looks up the levies
Two levies are charged on the interest. Their rates change by decree, so they depend on the date.
| KKDF, a fund levyCouncil of Ministers Decision 2010/974 | 15 % |
| BSMV, a tax on bankingPresidential Decision 7345 (Official Gazette 07.07.2023) | 15 % |
| Highest allocation fee allowed0.5 % of the amount, TCMB Communiqué 2020/7 | 500.00 |
3The first instalment, split
7,379.48 is paid. Less than a third of it reduces the debt.
4How the debt falls
Slowly at first, then faster: each month less interest, more principal.
5What is paid in total
177,607.76 for 100,000 borrowed.
6The rate on the poster, and the real one
The annual cost rate counts the levies and the fee too.
What comes back
Total repayment 177,607.76 TL, of which 77,607.76 is cost. Annual cost rate 84.5548 %. All 24 rows, each split as in step 3.
Legal basis: KKDF 15 %, Council of Ministers Decision 2010/974 · BSMV 15 %, Presidential Decision 7345 (Official Gazette 07.07.2023)
One command: bankmath plan 100000 0.0399 24 --product consumer --date 2026-11-10 --fee 500. Every figure above is its output.
The same question, different answers
Where no rule fixes the method, the method is a choice. The tool makes you name it.
A letter of guarantee, returned early
A teminat mektubu is a bank's written promise to pay if its customer does not. 10,000,000 TL at 2.40 % a year, reduced by 4,000,000 after five months, returned after ten. Commission and tax, in TL:
No law sets this formula. Neither figure is "the" answer.
A card statement, paid short
Statement 12,000 TL, minimum payment 2,400, only 1,000 paid. Which part of the debt gets the higher late rate? Interest on the next statement, in TL:
The tool follows the Regulation unless told otherwise. Which one a court would apply is not for it to say.
Every result lists the conventions it used.
What it covers
Six families of products.
Instalment loans
Repayment plan with levies, annual cost rate, early and partial repayment, late interest, "what can I borrow for 5,000 a month?"
Overdraft, revolving, spot
Interest day by day on a retail overdraft (KMH, the credit line on a current account), a business credit line or a loan repaid at maturity.
Credit cards
Minimum payment, rate ceilings, and the interest one statement puts on the next.
Bills and variable rates
Discounting a bill or cheque, plans that reprice, an overnight reference rate compounded.
Letters of guarantee
Commission period by period, under the convention you choose.
Regulated maximums
Is a quoted fee or rate within the maximum, and under which rule?
How an agent uses it
The agent decides what to ask. The tool computes. It reads no file, writes none, sends nothing.
18 read-only tools, none reads or writes a file. To connect it to Claude Code:
pip install "eqlx-bankmath[mcp]"
claude mcp add bankmath -- bankmath mcpHow it was tested
Two groups, kept apart: figures an authority printed, and parts where no authority printed any.
Matched to official figures
TCMB is the central bank; TLREF is the overnight lira reference rate.
Checked against their definition; no official example exists
Found on the way
Two printed figures in the regulation's annexes do not add up. The tests assert the right value and say why.
The whole
What it does not do
pip install "eqlx-bankmath[mcp]"
bankmath plan 100000 0.0399 24 --product consumer --date 2026-11-10 --fee 500
bankmath levies consumer 2026-11-10
bankmath tools # all 18 calculations with their arguments