IPMT in Collabora Office: Trace Interest Within a Fixed-Payment Schedule
Use Collabora IPMT to isolate a period’s interest, audit opening balances, and keep beginning-payment timing separate from end-payment timing.
Verification status: See the evidence and test scope described in this guide. How formula examples are checked
Quick answer: =IPMT(10%;1;3;1000;0;0) has independently expected result −100. It isolates the first period’s interest in a three-period, constant-payment schedule; it does not return the full payment or an interest rate.
Syntax and inputs
=IPMT(Rate; Period; NPer; PV [; FV [; Type]])
Rate is the per-period interest rate. Period is the particular period to inspect, NPer the total number of periods, and PV the opening present value. Optional FV is the terminal value and Type describes payment timing. These examples explicitly supply FV=0 and Type=0 for end-of-period payments.
The Collabora help includes a seven-year, 5% example and reports the interest amount for its fifth period. Despite ambiguous wording in parts of that example, the output is currency, not a percentage. Keep the result labeled “Interest payment” rather than “Interest rate.”
Example 1: isolate the first interest amount
Enter 10% in B2, 3 in B3 and 1000 in B4. In B6 enter =PMT(B2;B3;B4;0;0); its independently expected result is approximately −402.114803625.
In B7 enter =IPMT(B2;1;B3;B4;0;0). Expected result: −100, from the initial 1000 balance times the 10% rate, with an outflow sign.
The interest component is smaller than the payment because the remaining payment reduces principal. Subtracting interest from the negative total payment gives principal approximately −302.114803625.
Example 2: inspect every period
Enter period numbers 1, 2, 3 in A10:A12. In B10 enter =IPMT($B$2;A10;$B$3;$B$4;0;0) and fill down.
The independently expected interest magnitudes are approximately 100, 69.788519637, 36.555891239, with negative signs in the formula results. Interest declines because the positive outstanding principal declines after each payment.
To verify period two, the first closing balance is 1000+100−402.114803625, approximately 697.885196375. Its next interest is 10%, approximately 69.788519637. Use the opening balance for the period, not its closing balance, when checking end-of-period interest.
Advanced application: reconcile interest and principal
Add =PPMT($B$2;A10;$B$3;$B$4;0;0) in C10 and fill down. In D10 enter =B10+C10, then fill down. Each D row should match the constant PMT target when all inputs and timing agree.
The sum of the negative IPMT results is approximately −206.344410876. Its magnitude equals total unrounded payment magnitudes minus the original 1000 principal. This whole-schedule check can catch a missing period even if each remaining formula is valid.
Do not compare a monthly interest component with an annual PMT result. All three functions must use the same rate, period units, terminal value and timing.
Beginning-payment timing and scope
For payments at the beginning of a period, Type=1 changes the interest schedule. The first payment precedes interest accrual, so the independent annuity-due model has a first interest component of zero. That is a mathematical expectation, not a captured Collabora boundary result here.
Reconstruct a separate beginning-payment balance schedule if you need that model. Reusing the end-payment recurrence and merely changing the Type flag in one formula creates inconsistent controls.
Errors and troubleshooting
Use whole-number Period values from one through NPer in these examples. A missing or duplicated period produces an incomplete or double-counted total. The reviewed help does not establish every invalid-period error code or fractional-period coercion.
At a zero rate, the independent interest target is zero in every ordinary period. If nonzero interest appears, inspect the actual stored rate rather than its rounded display.
Keep full precision while reconciling totals. Posted payments rounded to cents may require a different final payment, which the constant-payment model does not automatically incorporate. Fees and changing-rate schedules are outside these formulas.
Availability and verification
Collabora Office 26.04 desktop help documents IPMT. The official snapshot was retrieved on 2026-10-13 and hash-verified for this guide on October 15, 2026. Online/mobile support is not inferred from this desktop documentation.
First introduced release and last functioning version are unknown. No native Collabora execution was performed. Expected outputs are independent arithmetic or equation controls, not captured application results. Exact native error behavior, additional versions and extreme numerical cases remain unverified.
References
Formulas use English function names and semicolon separators. The help advises supplying earlier optional arguments when a later optional argument is needed; the worked formulas use explicit values.