Byaj = amount × sekda ÷ 100 × months, where sekda is ₹ per ₹100 a month. Count whole calendar months from the date given, then leftover days at 1/30 of a month each. ₹1,00,000 at ₹2 sekda from 15 Jan to 10 Mar 2026 is 1 month 23 days: ₹3,533.33. A yearly % rate works too.
How byaj is calculated
Byaj = Amount × Sekda ÷ 100 × Months
Whole calendar months are counted from the date given. Leftover days count as 1/30 of a month each.
Month-by-month byaj and byaj per day
The Month-by-month byaj table splits the answer into calendar months counted from the date given: the byaj for each month and the total up to that date. Leftover days come last. The last line always equals the answer above it.
| Month | Up to | Byaj that month | Byaj so far |
|---|---|---|---|
| 1 | 15 Feb 2026 | ₹2,000 | ₹2,000 |
| + 23 days | 10 Mar 2026 | ₹1,533.33 | ₹3,533.33 |
Byaj every day is a month's byaj ÷ 30: ₹2,000 a month on ₹1,00,000 at ₹2 sekda is ₹66.67 a day. For a number of days without dates, or to compare with a bank's ÷ 365, use the interest per day calculator. To look up many amounts at one rate, see the byaj chart.
What people use the byaj calculator for
- Money lent to a friend or relative: enter the day you gave it and today, then send the working so nobody argues over the months.
- Shop udhar (credit): work out the byaj on an unpaid bill from the bill date at the rate you agreed.
- Girvi (pledged gold or silver) at a monthly rate: check the byaj asked for, counted in months and days from the date of the pledge.
- A claim at % a year from a date: when a notice or a court claim asks for interest at a yearly rate from a given date, switch to % a year and pick the two dates.
- Udhar with money paid back in between: use the part-payment interest calculator, where each payment clears byaj first.
Village interest (sekda) or bank interest (% a year)?
Both describe the same simple interest. In villages, bazaars and family lending, byaj is quoted in rupaye sekda (also said saikda): rupees per ₹100 a month. Banks quote % a year. Multiply sekda by 12 for the yearly rate: ₹1 sekda = 12% a year, ₹2 sekda = 24% a year. "2 taka" byaj is usually read as ₹2 sekda too.
Whatever you call it, byaj, sood or vyaj (the Marathi and Gujarati word), the sum is the same. The calculator keeps the rate in the unit you choose and never rounds it behind your back. See what rupaye sekda means.
When unpaid byaj earns byaj
Under More options you can add unpaid interest to the principal every month, quarter, half-year or year. That is compound interest (byaj par byaj). For a side-by-side comparison use the compound interest calculator.
8 short answersUsing the byaj calculator: quick answers
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Does the byaj calculator work from date to date?
Yes. Enter the date the money was given and the date you want byaj until, or tap Today for byaj up to today. It counts whole calendar months from the first date, then the leftover days at 1/30 of a month each. ₹1,00,000 at ₹2 sekda from 15 Jan to 10 Mar 2026 is 1 month 23 days: ₹3,533.33.
Can I calculate byaj for days, months or years?
Yes. Pick the two dates, or tap a quick period (3 months, 6 months, 1 year, 2 years), and the calculator counts the months and days between them. For a number of days without dates, the interest per day calculator is quicker: ₹1,00,000 at ₹2 sekda for 10 days is ₹666.67.
Can I use a yearly % rate instead of sekda?
Yes. Switch the rate to % a year and the box shows the same rate in sekda underneath: 12% a year = ₹1 sekda. Switching keeps the rate the same, so ₹2 sekda becomes 24%. ₹1,00,000 at 12% a year for 2 years is ₹24,000.
Can I see the byaj for each month?
Yes. With simple interest the result shows Byaj every month, and the Month-by-month byaj table lists each month's byaj and the total so far. On ₹1,00,000 at ₹1.5 sekda each month is ₹1,500, or ₹18,000 over a year. Both are hidden when byaj is added to the principal, because the monthly byaj then keeps growing.
Can it calculate chakravriddhi (compound) byaj?
Yes. Under More options, change Interest type to interest on interest every month, 3 months, 6 months or year; unpaid byaj is then added to the principal each time. ₹1,00,000 at ₹2 sekda for a year is ₹24,000 simple, or ₹26,824.18 added monthly. To compare year by year, use the compound interest calculator.
Which "How time is counted" option should I choose?
Keep Months + days, the default, for sekda loans and bahi accounts. Choose Actual days ÷ 365 to match a bank or finance company. Use the 30-day or ÷ 360 options only if your agreement says so. On ₹1,00,000 at 24% a year from 10 Jan to 25 Mar 2026, months + days gives ₹5,000 and actual days ÷ 365 gives ₹4,865.75.
What if part of the money was paid back in between?
Use the interest calculator with part payments. This one works out byaj on one amount between two dates; that one takes every amount lent and paid back with its date, lets each payment clear the byaj due first (the usual practice), and shows what is left. The rule is explained in part payment: interest first or principal first.
Why does the calculator show a damdupat warning?
It warns when unpaid byaj reaches 80% of the principal, and again when it reaches the full principal, because courts in some states do not allow more interest than the principal to be recovered at one time. On ₹1,00,000 at ₹2 sekda that is after 40 months (₹80,000 of byaj) and 50 months. See the damdupat rule.
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