Minor units (integer money)
Storing amounts as whole numbers of the smallest unit, such as paise, cents or fils, instead of decimals, so sums never drift by a fraction.
Updated October 2026 · with examples from our own builds
What does minor units mean in practice?
Computers store decimals such as 0.1 imprecisely, and tiny errors add up across thousands of transactions. Storing ₹149.50 as 14,950 paise keeps every calculation exact. Currencies differ in their smallest unit, with zero, two or three decimal places, so the system has to know which applies.
Nobody notices until something is off: a total wrong by a paisa, a refund that doesn't match, or a price displayed a hundred times too high because one part of the system expected cents and another expected dollars.
The rule is easy to state: integer minor units everywhere, including in data sent between systems, with conversion to a display format only at the edge.
Minor units at a glance
- Store as
- Whole numbers of paise, cents or fils
- Know per currency
- How many decimal places it has
- Convert
- Only when displaying
Where has minor units come up in our builds?
Money is integer paise everywhere in the system, including on the wire between the app and the API.
The first run of a 67-case billing suite booked a $499.00 charge for a $4.99 plan, because reference prices are stored in cents; it was fixed before anything shipped. The ledger is tested across currencies with zero, two and three decimal places.
Quantities are designed as integer thousandths of the item's unit and rates as integer paise, so a line's value is always computed exactly.
Common questions about minor units
Why does my app's total differ from my accountant's by a paisa?
Usually decimal rounding: amounts stored as floating-point numbers drift slightly across many calculations. Storing integer paise and rounding once, at a defined step, removes the drift.
Do all currencies have two decimal places?
No. Some have none and some have three, so the system should look up each currency's decimal places rather than assume two.
Related terms
Planning a product and not sure where minor units fits? Ask us, or browse all 116 terms in the glossary.