Calto evaluates your note line by line. Each line that contains an expression shows its result on the right. Lines that are plain text (like a heading) simply show nothing.
Arithmetic
| You type | Result |
|---|---|
12 * 4 + 3 | 51 |
(120 - 20) / 4 | 25 |
2^10 | 1,024 |
17 mod 5 | 2 |
-(3 + 4) | -7 |
^ is exponent and binds tighter than * and /. mod is the remainder.
Variables
Give a value a name with = and use it on any later line. Names can be English or Korean and must be one word (withTax, hotelNights); a space starts a new expression.
rent = 1200
utilities = 180
rent + utilities → 1,380Type a few letters of a name you already defined and Calto suggests it below the cursor.
Scale suffixes
k, M and B expand to thousand, million and billion.
budget = 2.5M → 2,500,000
budget / 10k → 250Percentages
| You type | Result | Meaning |
|---|---|---|
20% of 5000 | 1,000 | 20 percent of 5000 |
5% off 100 | 95 | discount |
10% on 200 | 220 | markup / tax added |
5000 * 20% | 1,000 | 20% alone is 0.2 |
Sections and sum / avg
A blank line starts a new section. sum (or total), avg (or average) and count work on the results in the current section only.
coffee = 4.5
lunch = 12
dinner = 8.5
sum → 25
taxi = 18
sum → 18prev
prev is the result of the previous line.
120 * 3 → 360
prev * 1.1 → 396Unit conversion
<value><unit> in <unit> converts between units of the same kind. 59 units across 10 categories: length, weight, volume, temperature, time, speed, data rate, data storage, area, angle.
10cm in inch → 3.94
5kg in lb → 11.02
100F in C → 37.78
100m2 in acre → 0.02
45deg in rad → 0.79Compound time adds up automatically: 2h 5min → 125 min, 1h 30min 15s → 5,415 s.
Currency
Six currencies: USD, KRW, EUR, JPY, CNY, GBP. Use codes, symbols or words (dollar, won, euro, yen, yuan, pound). Write yen or yuan as words: the ¥ sign is shared by both. Rates are live and cached for 24 hours, so the numbers below are only illustrative.
$100 in krw ≈ ₩147,000
€50 in USD ≈ $54
100 USD + 50000 KRW ≈ ₩197,000Mixed operations convert to the last currency on the line. sum in won converts a whole section.
Cryptocurrency works the same way for BTC, ETH, SOL, XRP, DOGE and ADA: 0.5 btc in usd.
Dates
today plus or minus a number of days, weeks, months or years gives a date.
today + 30 days → 2026-10-16
today - 2 weeks → 2026-09-02
today + 1 year → 2027-09-16Calto does not parse written dates like 2026-12-25; date math always starts from today.
Ratio and proportion
Write a proportion with ? in the unknown position and Calto solves it by cross-multiplying.
100 : 20 = 1550 : ? → 310
? : 3 = 12 : 9 → 4Functions
sqrt, abs, round, floor, ceil, sin, cos, tan, log (base 10), ln, exp.
sqrt(144) → 12
round(7.5) → 8When a line fails
A line that cannot be evaluated shows a short hint instead of a number: division by zero, an unknown unit or currency, an undefined variable, an unknown function, or a math domain error such as sqrt(-1).