How to Calculate a Dilution with C1V1 = C2V2
Solve for the missing term, then convert the answer into a bench instruction. The step almost everyone skips is that the solvent you add is V2 minus V1, not V2.
Lena Hoffmann · 9 min read
Guides & tutorials
Practical guides, how-tos and comparisons to get the most out of our free online tools.
June 9, 2026
How Long Does Alcohol Stay in Your System?
The body clears roughly one standard drink per hour. See how long alcohol stays in blood, breath and urine — and why you can't rush it.
Sofia Nunes · 2 min read
Is BMI Reliable? The Limitations of Body Mass Index
BMI is a quick screen, not a diagnosis. Learn what it misses — muscle, fat distribution, age — and what to check alongside it.
Sofia Nunes · 2 min read
How Much Water Should You Drink During Exercise?
Match your drinking to how much you sweat. Learn to estimate sweat rate and how much to sip per hour during a workout.
Sofia Nunes · 2 min read
June 8, 2026
What Is Slippage in Crypto? Price Impact, Tolerance and What It Costs
Price impact is arithmetic: on a constant-product pool it equals your trade size divided by the reserve plus your trade. Here is the formula, a table of trade size against impact, and why the setting called slippage tolerance changes none of it.
Camille Laurent · 7 min read
Grams to Milliliters for Cooking: Why They Are Not Always Equal
Grams measure weight and milliliters measure volume, so converting between them depends on density. Water is 1 gram per mL, but flour, sugar, and oil are not. Here is how to convert correctly.
Marco Bianchi · 3 min read
June 5, 2026
The Sortino Denominator Nobody Agrees On
On one twelve-month series the Sortino ratio is 7.7518 or 3.8759 depending only on whether the squared shortfalls are divided by all twelve months or by the three below target. The two conventions differ by exactly the square root of twelve over three, and they can rank two funds in opposite orders.
Camille Laurent · 13 min read
How Much Concrete Do You Need for Fence Posts?
Work out the concrete for setting fence posts: hole volume minus the post, converted into bags of ready-mix, with the rule of thumb for hole depth and width.
Marco Bianchi · 4 min read
How to Double a Recipe (Without Ruining It)
Doubling a recipe is more than multiplying by two. Learn the scale factor, which ingredients to scale carefully — spices, salt, leavening — and why bake time and pan size do not simply double.
Marco Bianchi · 4 min read
How to Predict a Half Marathon Time from a 5K or 10K
Use the Riegel formula to predict your half marathon time from a recent 5K or 10K, then turn that estimate into a realistic race-day pace with a smart pacing plan.
Aisha Karim · 5 min read
What Is a Capital Gain on Property?
A capital gain on property is the profit when you sell for more than you paid, minus your costs. Learn how it is calculated and why primary-residence rules matter.
Camille Laurent · 4 min read
June 4, 2026
How Wrong Is Nominal Minus Inflation? Exactly One Year's Inflation Wrong
The subtraction is not an approximation of the Fisher relation — it is the exact answer multiplied by (1 + i). At 8 percent nominal and 3 percent inflation the real return is 4.8544 percent, the shortcut says 5, and the error is exactly 3 percent of the answer. Always.
Camille Laurent · 12 min read