Savings & Investing

Interest Calculator

Project the growth of an account with a starting principal, annual additions, monthly additions, contribution timing, interest rate, investment length, taxes, and inflation. Review total contributions, gross interest, after-tax growth, and inflation-adjusted value over time.

Starting Principal

Annual Addition

Monthly Addition

Contribute

Interest Rate

Investment length

years

Tax Rate

Inflation Rate

There was an error with your calculation.

Interest

End Balance: $135,479.01

After Inflation Adjustment: $100,809.11

Total Principal: $99,000.00

Total Interest: $39,224.74

Total Interest after Tax: $36,479.01

Initial investment

Interest after tax

Contributions

Tax

0 yr

5 yr

10 yr

#	DEPOSIT	INTEREST	ENDING BALANCE
1	$32,400.00	$1,486.44	$33,886.44
2	$7,400.00	$1,908.58	$43,195.01
3	$7,400.00	$2,350.77	$52,945.78
4	$7,400.00	$2,813.97	$63,159.75
5	$7,400.00	$3,299.17	$73,858.93
6	$7,400.00	$3,807.43	$85,066.35
7	$7,400.00	$4,339.82	$96,806.18
8	$7,400.00	$4,897.51	$109,103.69
9	$7,400.00	$5,481.69	$121,985.38
10	$7,400.00	$6,093.62	$135,479.01

#	DEPOSIT	INTEREST	ENDING BALANCE
1	$30,200.00	$117.03	$30,317.03
2	$200.00	$118.25	$30,635.28
3	$200.00	$119.49	$30,954.77
4	$200.00	$120.72	$31,275.49
5	$200.00	$121.97	$31,597.46
6	$200.00	$123.22	$31,920.67
7	$200.00	$124.47	$32,245.14
8	$200.00	$125.72	$32,570.87
9	$200.00	$126.99	$32,897.85
10	$200.00	$128.25	$33,226.11
11	$200.00	$129.53	$33,555.63
12	$200.00	$130.80	$33,886.44
Year 1 End
13	$5,200.00	$151.46	$39,237.90
14	$200.00	$152.82	$39,590.72
15	$200.00	$154.19	$39,944.91
16	$200.00	$155.56	$40,300.47
17	$200.00	$156.94	$40,657.41
18	$200.00	$158.32	$41,015.73
19	$200.00	$159.71	$41,375.44
20	$200.00	$161.10	$41,736.55
21	$200.00	$162.50	$42,099.05
22	$200.00	$163.91	$42,462.96
23	$200.00	$165.32	$42,828.28
24	$200.00	$166.73	$43,195.01
Year 2 End
25	$5,200.00	$187.53	$48,582.54
26	$200.00	$189.03	$48,971.57
27	$200.00	$190.54	$49,362.11
28	$200.00	$192.05	$49,754.17
29	$200.00	$193.57	$50,147.74
30	$200.00	$195.10	$50,542.84
31	$200.00	$196.63	$50,939.47
32	$200.00	$198.17	$51,337.63
33	$200.00	$199.71	$51,737.34
34	$200.00	$201.26	$52,138.60
35	$200.00	$202.81	$52,541.41
36	$200.00	$204.37	$52,945.78
Year 3 End
37	$5,200.00	$225.31	$58,371.10
38	$200.00	$226.96	$58,798.06
39	$200.00	$228.62	$59,226.68
40	$200.00	$230.28	$59,656.96
41	$200.00	$231.95	$60,088.90
42	$200.00	$233.62	$60,522.52
43	$200.00	$235.30	$60,957.82
44	$200.00	$236.99	$61,394.81
45	$200.00	$238.68	$61,833.49
46	$200.00	$240.38	$62,273.87
47	$200.00	$242.09	$62,715.95
48	$200.00	$243.80	$63,159.75
Year 4 End
49	$5,200.00	$264.89	$68,624.65
50	$200.00	$266.70	$69,091.34
51	$200.00	$268.50	$69,559.85
52	$200.00	$270.32	$70,030.17
53	$200.00	$272.14	$70,502.31
54	$200.00	$273.97	$70,976.28
55	$200.00	$275.81	$71,452.09
56	$200.00	$277.65	$71,929.74
57	$200.00	$279.50	$72,409.24
58	$200.00	$281.36	$72,890.60
59	$200.00	$283.23	$73,373.83
60	$200.00	$285.10	$73,858.93
Year 5 End
61	$5,200.00	$306.35	$79,365.28
62	$200.00	$308.32	$79,873.60
63	$200.00	$310.29	$80,383.88
64	$200.00	$312.26	$80,896.14
65	$200.00	$314.25	$81,410.39
66	$200.00	$316.24	$81,926.63
67	$200.00	$318.24	$82,444.87
68	$200.00	$320.25	$82,965.12
69	$200.00	$322.26	$83,487.39
70	$200.00	$324.29	$84,011.67
71	$200.00	$326.32	$84,537.99
72	$200.00	$328.36	$85,066.35
Year 6 End
73	$5,200.00	$349.78	$90,616.14
74	$200.00	$351.91	$91,168.05
75	$200.00	$354.05	$91,722.10
76	$200.00	$356.20	$92,278.30
77	$200.00	$358.35	$92,836.65
78	$200.00	$360.52	$93,397.17
79	$200.00	$362.69	$93,959.86
80	$200.00	$364.87	$94,524.73
81	$200.00	$367.06	$95,091.79
82	$200.00	$369.26	$95,661.04
83	$200.00	$371.46	$96,232.50
84	$200.00	$373.68	$96,806.18
Year 7 End
85	$5,200.00	$395.27	$102,401.45
86	$200.00	$397.58	$102,999.03
87	$200.00	$399.90	$103,598.93
88	$200.00	$402.22	$104,201.15
89	$200.00	$404.55	$104,805.71
90	$200.00	$406.90	$105,412.60
91	$200.00	$409.25	$106,021.85
92	$200.00	$411.61	$106,633.46
93	$200.00	$413.98	$107,247.44
94	$200.00	$416.36	$107,863.80
95	$200.00	$418.75	$108,482.55
96	$200.00	$421.14	$109,103.69
Year 8 End
97	$5,200.00	$442.93	$114,746.62
98	$200.00	$445.42	$115,392.04
99	$200.00	$447.92	$116,039.96
100	$200.00	$450.43	$116,690.39
101	$200.00	$452.95	$117,343.34
102	$200.00	$455.48	$117,998.82
103	$200.00	$458.02	$118,656.84
104	$200.00	$460.57	$119,317.41
105	$200.00	$463.13	$119,980.54
106	$200.00	$465.70	$120,646.24
107	$200.00	$468.28	$121,314.52
108	$200.00	$470.87	$121,985.38
Year 9 End
109	$5,200.00	$492.84	$127,678.23
110	$200.00	$495.53	$128,373.76
111	$200.00	$498.22	$129,071.98
112	$200.00	$500.93	$129,772.91
113	$200.00	$503.65	$130,476.55
114	$200.00	$506.37	$131,182.92
115	$200.00	$509.11	$131,892.03
116	$200.00	$511.86	$132,603.89
117	$200.00	$514.62	$133,318.50
118	$200.00	$517.38	$134,035.89
119	$200.00	$520.16	$134,756.05
120	$200.00	$522.95	$135,479.01
Year 10 End

Input parameters

Starting Principal: Initial account balance.
Annual Addition: Amount deposited once per year.
Monthly Addition: Amount deposited each month.
Contribute: Timing of recurring contributions.
Interest Rate: The annual percentage rate used in the calculation.
Investment length: Number of years invested.
Tax Rate: Tax applied to investment earnings.
Inflation Rate: The expected annual increase in prices.

Understanding the results

Ending balance: Projected account value after contributions and interest.
Total contributions: All principal deposited.
Interest earned: Growth before or after applicable tax.
Inflation-adjusted value: Ending value expressed in current purchasing power.

Calculation principle

The balance compounds each period while additions, taxes, and inflation adjustments are applied according to the selected assumptions.

Read and validate the entered values.
Convert percentages and time periods into compatible units.
Apply the formulas below and present the calculated results.

Formulas

Compound growth FV = PV(1 + r)^n + FV(contributions)

After-tax interest Net interest = Interest × (1 − Tax rate)

Real value Real FV = FV / (1 + Inflation)^years

Symbols refer to the corresponding input and result labels shown above.

How to use this calculator

Enter your figures, choose any available options, and select Calculate. You can change the inputs as often as you like to compare scenarios.

Planning note

Results are estimates for education and planning. Taxes, lender rules, fees, and investment returns can vary, so verify important decisions with a qualified professional.