Compound Interest Calculator

Grow your savings at Nigerian rates — T-bills, fixed deposits, money market funds.

% p.a.
Future Value
₦5,482,316
Total Deposits
₦3,500,000
Interest Earned
₦1,982,316
Growth Factor
1.57x
Extended

Growth Chart & Frequency Analysis

Visualize compound growth and compare compounding frequencies

%
0.0M4.0M8.0M12.0M16.0M
Portfolio Value Total Deposited
Interest earns ₦9,480,960 on top of your ₦6,500,000 in deposits — a 2.46x growth factor.
Professional

Inflation-Adjusted & Withdrawal Simulator

Real vs nominal returns with inflation at Nigerian rates and withdrawal modeling

%
% p.a.
Nigeria inflation 2026: ~18–25% p.a. A real return requires beating inflation.
Nominal Value (Year 20)
Portfolio Value
₦94,577,468
Total Deposited
₦13,000,000
Real Value (Inflation-Adj.)
In Today's ₦
₦3,452,610
Real Gain
₦0
0.0M23.6M47.3M70.9M94.6M
Nominal Real (inflation-adj.) Deposits
YearNominal ValueReal ValueDepositedReal Gain
Year 1₦1,803,773₦1,528,621₦1,600,000₦71,379
Year 2₦2,736,755₦1,965,495₦2,200,000₦234,505
Year 3₦3,819,719₦2,324,799₦2,800,000₦475,201
Year 4₦5,076,774₦2,618,544₦3,400,000₦781,456
Year 5₦6,535,907₦2,856,905₦4,000,000₦1,143,095
Year 6₦8,229,601₦3,048,504₦4,600,000₦1,551,496
Year 7₦10,195,565₦3,200,643₦5,200,000₦1,999,357
Year 8₦12,477,566₦3,319,509₦5,800,000₦2,480,491
Year 9₦15,126,409₦3,410,341₦6,400,000₦2,989,659
Year 10₦18,201,066₦3,477,577₦7,000,000₦3,522,423
Year 11₦21,769,988₦3,524,976₦7,600,000₦4,075,024
Year 12₦25,912,630₦3,555,719₦8,200,000₦4,644,281
Year 13₦30,721,220₦3,572,501₦8,800,000₦5,227,499
Year 14₦36,302,813₦3,577,603₦9,400,000₦5,822,397
Year 15₦42,781,672₦3,572,956₦10,000,000₦6,427,044
Year 16₦50,302,038₦3,560,192₦10,600,000₦7,039,808
Year 17₦59,031,336₦3,540,695₦11,200,000₦7,659,305
Year 18₦69,163,907₦3,515,632₦11,800,000₦8,284,368
Year 19₦80,925,336₦3,485,992₦12,400,000₦8,914,008
Year 20₦94,577,468₦3,452,610₦13,000,000₦9,547,390

How to Use This Calculator

Investment Growth tab

Enter your initial investment and monthly contribution. The calculator shows how your money grows over time. The default rate of 15% reflects typical Nigerian T-bill yields. Use "More options" to change the compounding frequency — most Nigerian savings products compound monthly or annually.

Savings Goal tab

Know what you're saving for? Enter the target amount and when you need it. The calculator reverse-solves your required monthly contribution. If you already have savings, enter them as "Existing savings" — this reduces how much you need to add each month.

Compare tab

Compare two investment options side by side — for example, Treasury Bills at 22% vs a fixed deposit at 10%. See exactly how much more the higher-rate option earns over your chosen time frame.

Nigerian Investment Rates (2026)

Choosing the right rate is critical for accurate projections:

InvestmentTypical RateNotes
CBN Treasury Bills18–22% p.a.91-day, 182-day, 364-day
FGN Bonds16–20% p.a.Longer tenors, semi-annual coupon
Fixed Deposit (tier-1 banks)8–15% p.a.Varies by amount and tenor
Fixed Deposit (microfinance)12–18% p.a.Higher rates, higher risk
Money Market Funds18–22% p.a.Liquid, regulated by SEC
Stock Market (NGX)VariableHistorical: 15–25% long-term average
Savings Account4–8% p.a.CBN minimum savings rate

Rates above reflect 2026 conditions with CBN MPR at 26.5%. Rates change — check with your financial institution for current offers.

The Formula

Compound interest grows exponentially because interest is earned on previous interest:

A = P(1 + r/n)^(nt) + PMT × [(1 + r/n)^(nt) − 1] / (r/n) Where: A = future value P = initial principal r = annual rate (decimal, e.g. 0.15 for 15%) n = compounding frequency (12 = monthly, 4 = quarterly) t = time in years PMT = monthly contribution

For the Savings Goal tab, the formula is reversed to solve for PMT — the monthly amount needed to reach your target.

Example: Building an Emergency Fund

Tobi wants to save ₦3M in 3 years

Tobi already has ₦500K saved and can invest in Treasury Bills at 20% p.a., compounded monthly.

Savings Goal tab input:

Target₦3,000,000
Existing savings₦500,000
Rate20% p.a.
Years3

Result:

Required monthly savings≈ ₦52,000
Total deposited≈ ₦2,372,000
Interest earned≈ ₦628,000

The ₦628,000 in interest means Tobi reaches the goal by only depositing ₦1,872,000 in additional contributions — the interest accounts for over 21% of the final amount.

Compare: T-Bills vs Fixed Deposit

Using the Compare tab with ₦500K initial, 3 years:

T-Bills @ 20%₦896,000 final value
Fixed deposit @ 10%₦670,000 final value
Difference₦226,000 more with T-Bills

The 10% rate difference turns into a ₦226,000 real difference over 3 years — money that stays in your pocket.

FAQ

Nigerian Treasury Bill rates change at each CBN auction, typically every two weeks. In 2025–2026, rates have ranged from 18–22% p.a. for the 364-day bill. Check the CBN website (cbn.gov.ng) or your stockbroker for the latest stop rates. For long-term projections, using 15–18% as a conservative estimate is prudent.
Yes. Under NTA 2025: interest income from bank deposits is subject to withholding tax (WHT) at 10%, typically deducted at source. Treasury Bill income is generally exempt from personal income tax for individual investors. Capital gains tax (CGT) applies at 10% on disposal of certain assets. This calculator shows pre-tax returns — adjust your rate down by approximately 10% for after-tax bank deposit returns.
Nigeria's inflation rate is approximately 15–20% (2026). This means money loses purchasing power over time. If your investment earns 15% but inflation is 18%, your real return is negative. To estimate real returns, subtract inflation from your nominal rate: 20% T-bill rate - 16% inflation = ~4% real return. Treasury Bills have historically offered some protection against naira inflation, unlike savings accounts.
Money market funds (MMFs) pool investor money to buy T-bills, government bonds, and similar instruments. They offer similar rates (18–22%), are regulated by SEC Nigeria, and are more accessible — minimum investment can be as low as ₦1,000. Unlike direct T-bill purchases (minimum ~₦50M at CBN primary auction), MMFs allow small investors to access near-T-bill rates with daily liquidity.

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