What is this calculator?
This calculator builds a chit fund payment schedule in which the monthly contribution rises by a fixed increment each month, then compares everything you pay in against the payout you actually receive. It encodes no organizer rules whatsoever — every figure comes from you.
Use it when:
- Your chit group increases the monthly contribution by a fixed step each month.
- You know your payout amount and want to see what the chit cost or earned you overall.
- You are comparing the effect of withdrawing in an earlier or a later month.
Intended for: Members of chit funds, kuris, and committee schemes with a rising monthly contribution, who want a transparent comparison of contributions against payout.
How is this calculated?
- The schedule is generated month by month: month 1 is the starting contribution, and every later month adds one more increment.
- Due dates are laid out from the start date, keeping the same day of month.
- Contributions are accumulated to give the total paid across the full tenure, and the amount paid up to the withdrawal month is tracked separately.
- Commission is computed from your configuration and is either deducted from the payout or reported alongside it, according to the setting you choose.
- Net amount received is compared against total contributions to give the surplus or shortfall, in currency and as a percentage of what you paid.
- The same difference is restated in two more intuitive framings — what you get back per 100 contributed, and a simple multiplier — because a raw percentage alone is hard to reason about.
Formulas
Monthly instalment
Installment(n) = Starting amount + ((n − 1) × Increment)
The contribution grows by one fixed increment each month, so month 1 pays the starting amount and each later month pays a little more.
- n
- Month number, from 1 to the tenure
- Starting amount
- The contribution due in month 1
- Increment
- The fixed amount added to the contribution each month
Total contributions
Total paid = Σ Installment(n) for n = 1 … Tenure
Everything you pay into the chit across the whole tenure.
Surplus or shortfall
Difference = Net received − Total contributions
The gap between the money you received and the money you contributed. Positive is a surplus; negative is the cost of having received your money early.
Return per 100 contributed
Per 100 = Net received / Total contributions × 100
For every 100 you paid in, how much came back. Easier to compare across chits than a raw percentage.
Example
A 20-month chit starting at 5,000 per month with an increment of 100, withdrawing in month 8 for a payout of 105,000 with no commission.
- Month 1 pays 5,000, month 2 pays 5,100, and so on to month 20 at 6,900.
- Total contributions across 20 months are 119,000.
- By month 8 you have contributed 45,800, and 73,200 remains after the withdrawal.
- Net received 105,000 against 119,000 contributed leaves a shortfall of 14,000.
Result: Total contributions 119,000, net received 105,000, a shortfall of 14,000 — about 88.24 back per 100 contributed, which is the cost of taking the money in month 8 of 20.
Frequently asked questions
Why does a rising contribution make the comparison harder?
Because there is no single monthly figure to reason from. The calculator generates every month explicitly and totals it, so the comparison rests on the actual schedule rather than an average.
Why do I have to enter the withdrawal amount myself?
Because it is not derivable. In most chit groups the payout is decided by auction — members bid a discount, and the winner receives the chit value less that discount and the organizer's commission. Estimating it would mean inventing a bid, so the calculator asks you for the actual figure from your organizer.
Does this tell me whether my chit is a good investment?
No, and that is deliberate. It shows exactly what you paid, what you received, and the difference between them. Judging that as good or bad needs a benchmark — an alternative investment, or your own cost of borrowing — that the calculator has no way to know.
Why is there no annualised return or IRR?
A chit combines borrowing and saving in one instrument, and its cash flows have no single standard annualising convention. Quoting an IRR or annualised figure would suggest a comparability with fixed deposits or mutual funds that does not actually hold.
What does "return per 100 contributed" mean?
For every 100 units of currency you pay in across the whole tenure, it is how much you receive back. Above 100 means you came out ahead; below 100 means the chit cost you money, which is normal for an early withdrawal — you were effectively borrowing.
Does withdrawing early or late change the outcome?
Substantially. Withdrawing early means you receive money before you have contributed much, so you are borrowing and typically end below what you pay in. Withdrawing late means you have already contributed most of your commitment, so you are saving and typically end ahead. The calculator shows where in the tenure your withdrawal falls for exactly this reason.
Assumptions
What this calculator takes as given:
- Month 1 pays the starting contribution, and each later month adds exactly one increment.
- The withdrawal amount is exactly what you enter — it is never estimated, because chit payouts are set by auction or by the organizer and cannot be derived from the schedule.
- Organizer payout rules, auction mechanics, and bidding behaviour are not modelled in any way.
- The payment schedule follows precisely the values you enter: start date, tenure, and contribution pattern.
- Every instalment is assumed paid in full, on the due date, for the whole tenure.
- Due dates keep the day of month of the start date, month by month.
- Commission is applied exactly as you configure it — as a fixed amount or a percentage of the withdrawal, and deducted from the payout only if you say so.
Limitations
What this calculator cannot know or does not model:
- The actual amount your organizer pays out may differ from what you enter; only your organizer can confirm it.
- Commission and foreman policies vary widely between chit groups and jurisdictions, so no default is assumed.
- Taxes on any surplus received are not calculated.
- Dividends distributed to members from the auction discount are not modelled — if you receive them, enter their effect yourself.
- No annualised return, effective annual rate, IRR, or XIRR is reported. A chit has no standard, widely accepted annualising convention, and publishing one would imply a precision that does not exist.
- No "good" or "bad" verdict is given, because the calculator has no external benchmark to compare your chit against.
- Default by other members, group dissolution, and organizer insolvency are outside the calculation entirely.
References
- Chit Funds Act, 1982 — Government of India. The statute governing registered chit funds in India, including the ceiling on foreman commission. Rules vary by state and by scheme; confirm what applies to your group.