PDURATION Function in Google Sheets: Formula, Examples & Troubleshooting

=PDURATION(rate, present_value, future_value)

All three arguments are required. rate is the growth rate per period, present_value is the starting amount, and future_value is the desired amount. Google explicitly requires all three to be greater than zero. Its documented formula uses the difference of logarithms of the values divided by log(1+rate). Google PDURATION reference.

There is no payment or contribution argument. The rate and output share the same period unit: an annual effective growth rate yields years; a monthly rate yields months. The function has no date input and does not schedule an actual payment date.

Enter this model row:

1. In D2 enter =PDURATION(A2,B2,C2).
2. Expected result: approximately 5.268446244002589.
3. In E2 enter =B2*(1+A2)^D2. Expected reconstructed value: 15000.

The independent calculation is ln(15000/10000)/ln(1.08). The logarithms solve the compound-growth equation 15000 = 10000*1.08^n. The output is a count of periods, not a percentage or a currency amount.

If the model permits fractional compounding periods, 5.268446244 is its mathematical solution. If the balance only changes at complete period ends, inspect the nearest integer boundaries rather than treating the decimal fraction as an actual interest-credit date.

For the original inputs:

• =B2*(1+A2)^5 gives 14693.280768, below the target.
• =B2*(1+A2)^6 gives 15868.74322944, above the target.

For this positive-growth scenario, =ROUNDUP(D2,0) gives 6 complete periods. That rounding step is a reporting choice for the stated crediting assumption, not a change in PDURATION’s mathematical definition. A real agreement’s timing and rounding rules must be checked separately.

Put 6%, 8%, and 10% in G2:G4. In H2 enter =PDURATION(G2,10000,20000) and copy down. Expected doubling horizons are approximately:

These scenarios show how strongly the horizon depends on the assumed rate. They do not estimate the likelihood of any rate occurring. If the rate varies across periods or you contribute new amounts, a constant-rate no-flow horizon is no longer the same model.

For a simple exact check, =PDURATION(10%,100,121) has expected result 2, because 100*1.1^2 = 121.

With a positive rate and equal positive values, =PDURATION(8%,10000,10000) has the mathematical expectation 0: the target is already reached. For a lower positive target, the logarithmic equation produces a negative period count, describing the reverse direction of the growth model rather than a positive waiting time. Do not turn that into a future savings deadline.

A zero rate lies outside Google’s documented positive-input requirement. Even though a person can reason separately about no-growth scenarios, that does not authorize inventing the function’s exact zero-rate error behavior. Negative or zero values likewise fall outside the stated input scope.

Enter 8% or 0.08, not 8. The latter represents 800% per period and produces a completely different horizon. Check that the rate is per the intended period: using an annual effective rate as a monthly rate understates the time dramatically.

Retain unrounded D2 for the reconstruction check. A rounded six-period projection intentionally exceeds the original target. A date-formatted D2 is also misleading; format the result as a number of periods.

Google’s reference gives positivity requirements but not a complete invalid-input error-code matrix. No exact native error token or other-engine coercion rule is claimed here. Begin with the exact two-period check if an imported workbook behaves unexpectedly.

PDURATION is documented in the rolling Google Sheets service. First introduction, last functioning release, and retirement are not established by the reviewed sources. These examples are educational calculations without account access or a transaction.

Related published guides: LN, POWER, and ROUNDUP.

First-party source reviewed October 17, 2026: Google PDURATION.