Educational material from 
What you will learn
- Calculate changes in money and percent.
- Use starting value as the denominator.
- Recognise when deposits, dividends or fees require a different calculation.
The formula for a simple value change
Monetary change = ending value − starting value. Percentage change = (ending value − starting value) ÷ starting value × 100. Starting value must be greater than zero for this percentage calculation.
If SEK 1,000 becomes SEK 1,150, the difference is SEK 150. The calculation is 150 ÷ 1,000 × 100 = 15 percent. This lesson assumes that no money has been added or removed and that there are no dividends or fees.
Three fictional examples with the same starting value
A decrease gives a negative number because the ending value is lower than the starting value. An unchanged value gives zero. The percentage describes the size of the change relative to the amount present at the start.
A gain of SEK 200 means different things with different starting values. An increase from SEK 1,000 to SEK 1,200 is 20 percent. An increase from SEK 10,000 to SEK 10,200 is 2 percent. Money and percentages answer different questions.
If the table does not fit, scroll it sideways.
| Start | End | Difference | Change |
|---|---|---|---|
| SEK 1,000 | SEK 1,150 | +SEK 150 | +15 % |
| SEK 1,000 | SEK 800 | −SEK 200 | −20 % |
| SEK 1,000 | SEK 1,000 | SEK 0 | 0 % |
Calculate the whole portfolio before its percentage change
A fictional account starts with SEK 4,000 in A and SEK 6,000 in B. A rises 10 percent while B falls 5 percent. A becomes SEK 4,400 and B becomes SEK 5,700. The new total is SEK 10,100 compared with a starting total of SEK 10,000.
The change is 100 ÷ 10,000 × 100 = 1 percent. Simply averaging +10 and −5 gives +2.5 percent, which is wrong here because the parts were not equally large at the start.
Check using the starting weights: 0.40 × 10 % + 0.60 × −5 % = 1 %. This check applies to our simple case with the same period and no money flows. More advanced performance measurement needs explicit treatment of transactions and their timing, among other factors.
A deposit can look like a gain if you calculate incorrectly
Suppose an account starts at SEK 1,000, you add SEK 500, and it ends at SEK 1,500 without any price change. The account became larger, but the investments' value change was zero. Calling that a 50 percent return would confuse the deposit with performance.
Dividends and fees can also affect the result you want to measure. State what is included: price change alone, or a result that includes those other items. Do not compare two percentages before checking how both were calculated.
Finansinspektionen explains that shares can involve losses. A historical percentage or a successful practice result does not promise a future result.
Calculate with your own amounts
Compare two amounts in Swedish kronor (SEK) from the start and end of the same period. The calculator uses (ending value − starting value) ÷ starting value × 100. Try a higher, lower or unchanged ending value.
Use a simple practice case with no deposits, withdrawals, dividends, fees or tax during the period. The calculator shows the value change over the whole period, rather than a yearly rate or a future result.
Calculated from 1,000 SEK to 1,150 SEK.
- Change in SEK
- +150 SEK
- Percentage change
- +15 %
(1,150 − 1,000) ÷ 1,000 × 100
Percentages display at most two decimal places. A change between zero and 0.01 percent is labelled as a small increase or decrease so it is not confused with an unchanged value.
Need to calculate a different case?
Try it yourself
A fictional holding starts at SEK 2,000 and ends at SEK 1,700. No money is added or removed. What is the change in money and percent?
Show the solution and explanation
−SEK 300 and −15 percent.
1,700 − 2,000 = −SEK 300. Divide by the starting value: −300 ÷ 2,000 × 100 = −15 %. Using the ending value as the denominator would answer a different question.
Check your understanding
Why does the simple formula use starting value?
It describes the change relative to the value present at the beginning. Dividing by ending value does not give the same start-to-end percentage change.
Do equal changes in money always represent equal percentages?
No. An increase of SEK 100 from SEK 500 is 20 percent. An increase of SEK 100 from SEK 1,000 is 10 percent.
Practise with virtual money
Try what you just learned in a practice portfolio with virtual money. You don't deposit any real money.
How the practice portfolio worksKeep learning and practising
More lessons on this topic
Start here: shares and portfolios
Sources and examples
The sources support the factual explanations. Calculations and exercises were created for this lesson. Amounts and price changes are invented unless stated otherwise.
This material is educational and does not recommend securities to buy. A simulated result does not guarantee a future result.
